Make C++ types impl `Core.Default`. (#6962)

C++ classes that are default-constructible now implement `Core.Default`
by calling the default constructor.

core/prelude/default.carbon

@@ -45,7 +45,7 @@ interface DefaultOrUnformed {
 
 final impl forall [T:! Default] T as DefaultOrUnformed {
   fn Op() -> Self {
-    return T.Op();
+    return T.(Default.Op)();
   }
 }
 

examples/interop/cpp/socket.carbon

@@ -40,9 +40,8 @@ fn Run() -> i32 {
     return 1;
   }
 
-  // TODO: This initialization should zero-initialize the struct.
-  // TODO: We should be able to use simply `= ()` or `= {}` to get the same effect.
-  var address: Cpp.sockaddr_in6 = Cpp.sockaddr_in6.sockaddr_in6();
+  // TODO: We should be able to use `= ()` or `= {}` to perform zero-initialization.
+  var address: Cpp.sockaddr_in6;
   Cpp.memset(&address, 0, Cpp.SOCKADDR_IN_SIZE);
   // TODO: Should this be valid without a cast? `AF_INET6` is defined to an
   // integer literal in glibc at least, but we import it as an `i32`.

toolchain/check/core_identifier.def

@@ -35,6 +35,7 @@ CARBON_CORE_IDENTIFIER(Copy)
 CARBON_CORE_IDENTIFIER(CppCompat)
 CARBON_CORE_IDENTIFIER(CppUnsafeDeref)
 CARBON_CORE_IDENTIFIER(Dec)
+CARBON_CORE_IDENTIFIER(Default)
 CARBON_CORE_IDENTIFIER(DefaultOrUnformed)
 CARBON_CORE_IDENTIFIER(Destroy)
 CARBON_CORE_IDENTIFIER(DivAssignWith)

toolchain/check/cpp/impl_lookup.cpp

@@ -119,31 +119,6 @@ static auto BuildCopyWitness(
                             query_specific_interface_id, {fn_id});
 }
 
-static auto BuildDestroyWitness(
-    Context& context, SemIR::LocId loc_id,
-    SemIR::ConstantId query_self_const_id,
-    SemIR::SpecificInterfaceId query_specific_interface_id,
-    const TypeStructure* best_impl_type_structure,
-    SemIR::LocId best_impl_loc_id) -> SemIR::InstId {
-  auto& clang_sema = context.clang_sema();
-
-  // TODO: This should provide `Destroy` for enums and other trivially
-  // destructible types.
-  auto* class_decl = TypeAsClassDecl(context, query_self_const_id);
-  if (!class_decl) {
-    return SemIR::InstId::None;
-  }
-  auto decl_info = DeclInfo{.decl = clang_sema.LookupDestructor(class_decl),
-                            .signature = {.num_params = 0}};
-  auto fn_id = GetFunctionId(context, loc_id, decl_info,
-                             best_impl_type_structure, best_impl_loc_id);
-  if (fn_id == SemIR::ErrorInst::InstId || fn_id == SemIR::InstId::None) {
-    return fn_id;
-  }
-  return BuildCustomWitness(context, loc_id, query_self_const_id,
-                            query_specific_interface_id, {fn_id});
-}
-
 static auto BuildCppUnsafeDerefWitness(
     Context& context, SemIR::LocId loc_id,
     SemIR::ConstantId query_self_const_id,
@@ -187,6 +162,61 @@ static auto BuildCppUnsafeDerefWitness(
                             {result_type_id, fn_id});
 }
 
+static auto BuildDefaultWitness(
+    Context& context, SemIR::LocId loc_id,
+    SemIR::ConstantId query_self_const_id,
+    SemIR::SpecificInterfaceId query_specific_interface_id,
+    const TypeStructure* best_impl_type_structure,
+    SemIR::LocId best_impl_loc_id) -> SemIR::InstId {
+  auto& clang_sema = context.clang_sema();
+
+  auto* class_decl = TypeAsClassDecl(context, query_self_const_id);
+  if (!class_decl) {
+    return SemIR::InstId::None;
+  }
+  // Clang would produce a warning for classes with uninitialized
+  // [[clang::requires_init]] fields for which default initialization is
+  // performed, and we don't have a good place to produce that warning.
+  // That happens if class_decl->hasUninitializedExplicitInitFields() is true.
+  //
+  // TODO: Consider treating such types as not implementing `Default`.
+  auto decl_info =
+      DeclInfo{.decl = clang_sema.LookupDefaultConstructor(class_decl),
+               .signature = {.num_params = 0}};
+  auto fn_id = GetFunctionId(context, loc_id, decl_info,
+                             best_impl_type_structure, best_impl_loc_id);
+  if (fn_id == SemIR::ErrorInst::InstId || fn_id == SemIR::InstId::None) {
+    return fn_id;
+  }
+  return BuildCustomWitness(context, loc_id, query_self_const_id,
+                            query_specific_interface_id, {fn_id});
+}
+
+static auto BuildDestroyWitness(
+    Context& context, SemIR::LocId loc_id,
+    SemIR::ConstantId query_self_const_id,
+    SemIR::SpecificInterfaceId query_specific_interface_id,
+    const TypeStructure* best_impl_type_structure,
+    SemIR::LocId best_impl_loc_id) -> SemIR::InstId {
+  auto& clang_sema = context.clang_sema();
+
+  // TODO: This should provide `Destroy` for enums and other trivially
+  // destructible types.
+  auto* class_decl = TypeAsClassDecl(context, query_self_const_id);
+  if (!class_decl) {
+    return SemIR::InstId::None;
+  }
+  auto decl_info = DeclInfo{.decl = clang_sema.LookupDestructor(class_decl),
+                            .signature = {.num_params = 0}};
+  auto fn_id = GetFunctionId(context, loc_id, decl_info,
+                             best_impl_type_structure, best_impl_loc_id);
+  if (fn_id == SemIR::ErrorInst::InstId || fn_id == SemIR::InstId::None) {
+    return fn_id;
+  }
+  return BuildCustomWitness(context, loc_id, query_self_const_id,
+                            query_specific_interface_id, {fn_id});
+}
+
 auto LookupCppImpl(Context& context, SemIR::LocId loc_id,
                    CoreInterface core_interface,
                    SemIR::ConstantId query_self_const_id,
@@ -198,14 +228,18 @@ auto LookupCppImpl(Context& context, SemIR::LocId loc_id,
       return BuildCopyWitness(context, loc_id, query_self_const_id,
                               query_specific_interface_id,
                               best_impl_type_structure, best_impl_loc_id);
-    case CoreInterface::Destroy:
-      return BuildDestroyWitness(context, loc_id, query_self_const_id,
-                                 query_specific_interface_id,
-                                 best_impl_type_structure, best_impl_loc_id);
     case CoreInterface::CppUnsafeDeref:
       return BuildCppUnsafeDerefWitness(
           context, loc_id, query_self_const_id, query_specific_interface_id,
           best_impl_type_structure, best_impl_loc_id);
+    case CoreInterface::Default:
+      return BuildDefaultWitness(context, loc_id, query_self_const_id,
+                                 query_specific_interface_id,
+                                 best_impl_type_structure, best_impl_loc_id);
+    case CoreInterface::Destroy:
+      return BuildDestroyWitness(context, loc_id, query_self_const_id,
+                                 query_specific_interface_id,
+                                 best_impl_type_structure, best_impl_loc_id);
 
     // IntFitsIn is for Carbon integer types only.
     case CoreInterface::IntFitsIn:

toolchain/check/custom_witness.cpp

@@ -304,9 +304,10 @@ auto GetCoreInterface(Context& context, SemIR::InterfaceId interface_id)
 
   constexpr auto CoreIdentifiersToInterfaces = std::array{
       std::pair{CoreIdentifier::Copy, CoreInterface::Copy},
+      std::pair{CoreIdentifier::CppUnsafeDeref, CoreInterface::CppUnsafeDeref},
+      std::pair{CoreIdentifier::Default, CoreInterface::Default},
       std::pair{CoreIdentifier::Destroy, CoreInterface::Destroy},
-      std::pair{CoreIdentifier::IntFitsIn, CoreInterface::IntFitsIn},
-      std::pair{CoreIdentifier::CppUnsafeDeref, CoreInterface::CppUnsafeDeref}};
+      std::pair{CoreIdentifier::IntFitsIn, CoreInterface::IntFitsIn}};
 
   for (auto [core_identifier, core_interface] : CoreIdentifiersToInterfaces) {
     if (interface.name_id ==
@@ -485,8 +486,9 @@ auto LookupCustomWitness(Context& context, SemIR::LocId loc_id,
     case CoreInterface::IntFitsIn:
       return MakeIntFitsInWitness(context, loc_id, query_self_const_id,
                                   query_specific_interface_id);
-    case CoreInterface::CppUnsafeDeref:
     case CoreInterface::Copy:
+    case CoreInterface::CppUnsafeDeref:
+    case CoreInterface::Default:
     case CoreInterface::Unknown:
       // TODO: Handle more interfaces, particularly copy, move, and conversion.
       return std::nullopt;

toolchain/check/custom_witness.h

@@ -23,9 +23,10 @@ auto BuildCustomWitness(Context& context, SemIR::LocId loc_id,
 // can have custom witnesses.
 enum class CoreInterface {
   Copy,
+  CppUnsafeDeref,
+  Default,
   Destroy,
   IntFitsIn,
-  CppUnsafeDeref,
 
   Unknown,
 };

toolchain/check/testdata/alias/import.carbon

@@ -74,10 +74,10 @@ var c: () = a_alias_alias;
 // CHECK:STDOUT:   %ptr: type = ptr_type %C [concrete]
 // CHECK:STDOUT:   %pattern_type.506: type = pattern_type %ptr [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.910: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.910: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.7ef: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.b07: %T.as.DefaultOrUnformed.impl.Op.type.7ef = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %ptr, (%DefaultOrUnformed.impl_witness.910) [concrete]
@@ -92,7 +92,7 @@ var c: () = a_alias_alias;
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -147,10 +147,10 @@ var c: () = a_alias_alias;
 // CHECK:STDOUT:   %ptr: type = ptr_type %C [concrete]
 // CHECK:STDOUT:   %pattern_type.506: type = pattern_type %ptr [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.20b: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.20b: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.ae0, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.7ef: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.b07: %T.as.DefaultOrUnformed.impl.Op.type.7ef = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %ptr, (%DefaultOrUnformed.impl_witness.20b) [concrete]
@@ -170,7 +170,7 @@ var c: () = a_alias_alias;
 // CHECK:STDOUT:   %Main.import_ref.743 = import_ref Main//class1, inst{{[0-9A-F]+}} [no loc], unloaded
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Main.import_ref.dee: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Main//class1, inst{{[0-9A-F]+}} [indirect], loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Main.import_ref.dee), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.ae0 = impl_witness_table (%Main.import_ref.dee), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -226,10 +226,10 @@ var c: () = a_alias_alias;
 // CHECK:STDOUT:   %ptr: type = ptr_type %C [concrete]
 // CHECK:STDOUT:   %pattern_type.506: type = pattern_type %ptr [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.910: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.910: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.7ef: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.b07: %T.as.DefaultOrUnformed.impl.Op.type.7ef = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %ptr, (%DefaultOrUnformed.impl_witness.910) [concrete]
@@ -248,7 +248,7 @@ var c: () = a_alias_alias;
 // CHECK:STDOUT:   %Main.import_ref.a60 = import_ref Main//class2, inst{{[0-9A-F]+}} [indirect], unloaded
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/array/basics.carbon

@@ -232,15 +232,15 @@ var a: array(1, 1);
 // CHECK:STDOUT:   %array_type: type = array_type %int_3, %empty_tuple.type [concrete]
 // CHECK:STDOUT:   %pattern_type.035: type = pattern_type %array_type [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.924: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%array_type) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.924: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%array_type) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.86d: %DefaultOrUnformed.type = facet_value %array_type, (%DefaultOrUnformed.impl_witness.924) [concrete]
 // CHECK:STDOUT:   %tuple.type: type = tuple_type (%empty_tuple.type, %empty_tuple.type, %empty_tuple.type) [concrete]
 // CHECK:STDOUT:   %tuple: %tuple.type = tuple_value (%empty_tuple, %empty_tuple, %empty_tuple) [concrete]
 // CHECK:STDOUT:   %pattern_type.8c1: type = pattern_type %tuple.type [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.032: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%tuple.type) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.032: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%tuple.type) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.1ea: %DefaultOrUnformed.type = facet_value %tuple.type, (%DefaultOrUnformed.impl_witness.032) [concrete]
 // CHECK:STDOUT:   %Destroy.Op.type.bae255.1: type = fn_type @Destroy.Op.loc8 [concrete]
 // CHECK:STDOUT:   %Destroy.Op.651ba6.1: %Destroy.Op.type.bae255.1 = struct_value () [concrete]
@@ -250,7 +250,7 @@ var a: array(1, 1);
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @G() {

toolchain/check/testdata/class/field/field_access.carbon

@@ -45,7 +45,7 @@ fn Run() {
 // CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.3d0: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.cda: %T.as.DefaultOrUnformed.impl.Op.type.3d0 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %Class, (%DefaultOrUnformed.impl_witness.6ca) [concrete]
@@ -102,7 +102,7 @@ fn Run() {
 // CHECK:STDOUT:   %Core.Int: %Int.type = import_ref Core//prelude/parts/int, Int, loaded [concrete = constants.%Int.generic]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.ImplicitAs: %ImplicitAs.type.cc7 = import_ref Core//prelude/parts/as, ImplicitAs, loaded [concrete = constants.%ImplicitAs.generic]
 // CHECK:STDOUT:   %Core.import_ref.42d: @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert.type (%Core.IntLiteral.as.ImplicitAs.impl.Convert.type.4e6) = import_ref Core//prelude/parts/int, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert (constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.3c2)]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.74f = impl_witness_table (%Core.import_ref.42d), @Core.IntLiteral.as.ImplicitAs.impl [concrete]

toolchain/check/testdata/class/field/field_access_in_value.carbon

@@ -46,7 +46,7 @@ fn Test() {
 // CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.3d0: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.cda: %T.as.DefaultOrUnformed.impl.Op.type.3d0 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %Class, (%DefaultOrUnformed.impl_witness.6ca) [concrete]
@@ -103,7 +103,7 @@ fn Test() {
 // CHECK:STDOUT:   %Core.Int: %Int.type = import_ref Core//prelude/parts/int, Int, loaded [concrete = constants.%Int.generic]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.ImplicitAs: %ImplicitAs.type.cc7 = import_ref Core//prelude/parts/as, ImplicitAs, loaded [concrete = constants.%ImplicitAs.generic]
 // CHECK:STDOUT:   %Core.import_ref.42d: @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert.type (%Core.IntLiteral.as.ImplicitAs.impl.Convert.type.4e6) = import_ref Core//prelude/parts/int, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert (constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.3c2)]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.74f = impl_witness_table (%Core.import_ref.42d), @Core.IntLiteral.as.ImplicitAs.impl [concrete]

toolchain/check/testdata/class/generic/call.carbon

@@ -96,7 +96,7 @@ class Outer(T:! type) {
 // CHECK:STDOUT:   %type: type = facet_type <type> [concrete]
 // CHECK:STDOUT:   %.Self: %type = symbolic_binding .Self [symbolic_self]
 // CHECK:STDOUT:   %pattern_type.98f: type = pattern_type type [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
 // CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [concrete]
 // CHECK:STDOUT:   %Int.type: type = generic_class_type @Int [concrete]
 // CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
@@ -106,7 +106,7 @@ class Outer(T:! type) {
 // CHECK:STDOUT:   %N.6f3: %i32 = symbolic_binding N, 1 [symbolic]
 // CHECK:STDOUT:   %Class.type: type = generic_class_type @Class [concrete]
 // CHECK:STDOUT:   %Class.generic: %Class.type = struct_value () [concrete]
-// CHECK:STDOUT:   %Class.e86: type = class_type @Class, @Class(%T, %N.6f3) [symbolic]
+// CHECK:STDOUT:   %Class.e86: type = class_type @Class, @Class(%T.67d, %N.6f3) [symbolic]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type.357: <witness> = complete_type_witness %empty_struct_type [concrete]
 // CHECK:STDOUT:   %ptr.235: type = ptr_type %i32 [concrete]
@@ -130,9 +130,9 @@ class Outer(T:! type) {
 // CHECK:STDOUT:   %Class.ff1: type = class_type @Class, @Class(%ptr.235, %int_5.0f6) [concrete]
 // CHECK:STDOUT:   %pattern_type.d58: type = pattern_type %Class.ff1 [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.77b: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Class.ff1) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.77b: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Class.ff1) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.b8a: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Class.ff1) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.090: %T.as.DefaultOrUnformed.impl.Op.type.b8a = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.31a: %DefaultOrUnformed.type = facet_value %Class.ff1, (%DefaultOrUnformed.impl_witness.77b) [concrete]
@@ -144,7 +144,7 @@ class Outer(T:! type) {
 // CHECK:STDOUT:   %int_0.6a9: %i32 = int_value 0 [concrete]
 // CHECK:STDOUT:   %Class.7c6: type = class_type @Class, @Class(%empty_tuple.type, %int_0.6a9) [concrete]
 // CHECK:STDOUT:   %pattern_type.a3c: type = pattern_type %Class.7c6 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.c95: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Class.7c6) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.c95: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Class.7c6) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.7ec: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Class.7c6) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.b11: %T.as.DefaultOrUnformed.impl.Op.type.7ec = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.d1f: %DefaultOrUnformed.type = facet_value %Class.7c6, (%DefaultOrUnformed.impl_witness.c95) [concrete]
@@ -165,7 +165,7 @@ class Outer(T:! type) {
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.74f = impl_witness_table (%Core.import_ref.42d), @Core.IntLiteral.as.ImplicitAs.impl [concrete]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -184,7 +184,7 @@ class Outer(T:! type) {
 // CHECK:STDOUT:       %.Self.2: %type = symbolic_binding .Self [symbolic_self = constants.%.Self]
 // CHECK:STDOUT:       %.loc4_17.2: type = type_literal type [concrete = type]
 // CHECK:STDOUT:     }
-// CHECK:STDOUT:     %T.loc4_13.2: type = symbolic_binding T, 0 [symbolic = %T.loc4_13.1 (constants.%T)]
+// CHECK:STDOUT:     %T.loc4_13.2: type = symbolic_binding T, 0 [symbolic = %T.loc4_13.1 (constants.%T.67d)]
 // CHECK:STDOUT:     %.loc4_27: type = splice_block %i32 [concrete = constants.%i32] {
 // CHECK:STDOUT:       %.Self.1: %type = symbolic_binding .Self [symbolic_self = constants.%.Self]
 // CHECK:STDOUT:       %i32: type = type_literal constants.%i32 [concrete = constants.%i32]
@@ -234,7 +234,7 @@ class Outer(T:! type) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: generic class @Class(%T.loc4_13.2: type, %N.loc4_23.2: %i32) {
-// CHECK:STDOUT:   %T.loc4_13.1: type = symbolic_binding T, 0 [symbolic = %T.loc4_13.1 (constants.%T)]
+// CHECK:STDOUT:   %T.loc4_13.1: type = symbolic_binding T, 0 [symbolic = %T.loc4_13.1 (constants.%T.67d)]
 // CHECK:STDOUT:   %N.loc4_23.1: %i32 = symbolic_binding N, 1 [symbolic = %N.loc4_23.1 (constants.%N.6f3)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
@@ -269,8 +269,8 @@ class Outer(T:! type) {
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Class(constants.%T, constants.%N.6f3) {
-// CHECK:STDOUT:   %T.loc4_13.1 => constants.%T
+// CHECK:STDOUT: specific @Class(constants.%T.67d, constants.%N.6f3) {
+// CHECK:STDOUT:   %T.loc4_13.1 => constants.%T.67d
 // CHECK:STDOUT:   %N.loc4_23.1 => constants.%N.6f3
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/class/generic/stringify.carbon

@@ -103,10 +103,10 @@ var g: E({.a = 1, .b = 2}) = {} as E({.a = 3, .b = 4} as D);
 // CHECK:STDOUT:   %EmptyParams: type = class_type @EmptyParams [concrete]
 // CHECK:STDOUT:   %pattern_type.8ec: type = pattern_type %NoParams [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.d7c: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%NoParams) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.d7c: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%NoParams) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.51c: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%NoParams) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.5bb: %T.as.DefaultOrUnformed.impl.Op.type.51c = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %NoParams, (%DefaultOrUnformed.impl_witness.d7c) [concrete]
@@ -125,7 +125,7 @@ var g: E({.a = 1, .b = 2}) = {} as E({.a = 3, .b = 4} as D);
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.ImplicitAs: %ImplicitAs.type.cc7 = import_ref Core//prelude/parts/as, ImplicitAs, loaded [concrete = constants.%ImplicitAs.generic]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -197,14 +197,14 @@ var g: E({.a = 1, .b = 2}) = {} as E({.a = 3, .b = 4} as D);
 // CHECK:STDOUT:   %type: type = facet_type <type> [concrete]
 // CHECK:STDOUT:   %.Self: %type = symbolic_binding .Self [symbolic_self]
 // CHECK:STDOUT:   %pattern_type.98f: type = pattern_type type [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
 // CHECK:STDOUT:   %Outer.type: type = generic_class_type @Outer [concrete]
 // CHECK:STDOUT:   %Outer.generic: %Outer.type = struct_value () [concrete]
-// CHECK:STDOUT:   %Outer.387: type = class_type @Outer, @Outer(%T) [symbolic]
+// CHECK:STDOUT:   %Outer.387: type = class_type @Outer, @Outer(%T.67d) [symbolic]
 // CHECK:STDOUT:   %U: type = symbolic_binding U, 1 [symbolic]
-// CHECK:STDOUT:   %Inner.type.e0d: type = generic_class_type @Inner, @Outer(%T) [symbolic]
+// CHECK:STDOUT:   %Inner.type.e0d: type = generic_class_type @Inner, @Outer(%T.67d) [symbolic]
 // CHECK:STDOUT:   %Inner.generic.ada: %Inner.type.e0d = struct_value () [symbolic]
-// CHECK:STDOUT:   %Inner.e21: type = class_type @Inner, @Inner(%T, %U) [symbolic]
+// CHECK:STDOUT:   %Inner.e21: type = class_type @Inner, @Inner(%T.67d, %U) [symbolic]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type.357: <witness> = complete_type_witness %empty_struct_type [concrete]
 // CHECK:STDOUT:   %empty_struct: %empty_struct_type = struct_value () [concrete]
@@ -214,9 +214,9 @@ var g: E({.a = 1, .b = 2}) = {} as E({.a = 3, .b = 4} as D);
 // CHECK:STDOUT:   %Inner.generic.0f6: %Inner.type.cd9 = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.acf: type = pattern_type %Outer.b7c [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8e7: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Outer.b7c) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8e7: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Outer.b7c) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.e70: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Outer.b7c) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.3a0: %T.as.DefaultOrUnformed.impl.Op.type.e70 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %Outer.b7c, (%DefaultOrUnformed.impl_witness.8e7) [concrete]
@@ -243,7 +243,7 @@ var g: E({.a = 1, .b = 2}) = {} as E({.a = 3, .b = 4} as D);
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Int: %Int.type = import_ref Core//prelude/parts/int, Int, loaded [concrete = constants.%Int.generic]
 // CHECK:STDOUT:   %Core.ImplicitAs: %ImplicitAs.type.cc7 = import_ref Core//prelude/parts/as, ImplicitAs, loaded [concrete = constants.%ImplicitAs.generic]
 // CHECK:STDOUT: }
@@ -263,7 +263,7 @@ var g: E({.a = 1, .b = 2}) = {} as E({.a = 3, .b = 4} as D);
 // CHECK:STDOUT:       %.Self: %type = symbolic_binding .Self [symbolic_self = constants.%.Self]
 // CHECK:STDOUT:       %.loc4_17.2: type = type_literal type [concrete = type]
 // CHECK:STDOUT:     }
-// CHECK:STDOUT:     %T.loc4_13.2: type = symbolic_binding T, 0 [symbolic = %T.loc4_13.1 (constants.%T)]
+// CHECK:STDOUT:     %T.loc4_13.2: type = symbolic_binding T, 0 [symbolic = %T.loc4_13.1 (constants.%T.67d)]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %v.patt: %pattern_type.acf = ref_binding_pattern v [concrete]
@@ -300,7 +300,7 @@ var g: E({.a = 1, .b = 2}) = {} as E({.a = 3, .b = 4} as D);
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: generic class @Outer(%T.loc4_13.2: type) {
-// CHECK:STDOUT:   %T.loc4_13.1: type = symbolic_binding T, 0 [symbolic = %T.loc4_13.1 (constants.%T)]
+// CHECK:STDOUT:   %T.loc4_13.1: type = symbolic_binding T, 0 [symbolic = %T.loc4_13.1 (constants.%T.67d)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %Inner.type: type = generic_class_type @Inner, @Outer(%T.loc4_13.1) [symbolic = %Inner.type (constants.%Inner.type.e0d)]
@@ -355,11 +355,11 @@ var g: E({.a = 1, .b = 2}) = {} as E({.a = 3, .b = 4} as D);
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Outer(constants.%T) {
-// CHECK:STDOUT:   %T.loc4_13.1 => constants.%T
+// CHECK:STDOUT: specific @Outer(constants.%T.67d) {
+// CHECK:STDOUT:   %T.loc4_13.1 => constants.%T.67d
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @Inner(constants.%T, constants.%U) {
+// CHECK:STDOUT: specific @Inner(constants.%T.67d, constants.%U) {
 // CHECK:STDOUT:   %U.loc5_15.1 => constants.%U
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/class/import.carbon

@@ -221,7 +221,7 @@ fn Run() {
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fb9: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%ptr.8c3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fb9: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%ptr.8c3) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.3ad: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%ptr.8c3) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.5f6: %T.as.DefaultOrUnformed.impl.Op.type.3ad = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %ptr.8c3, (%DefaultOrUnformed.impl_witness.fb9) [concrete]
@@ -274,7 +274,7 @@ fn Run() {
 // CHECK:STDOUT:   %Copy.impl_witness_table.c3a = impl_witness_table (%Core.import_ref.203), @ptr.as.Copy.impl [concrete]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/class/import_member_cycle.carbon

@@ -81,10 +81,10 @@ fn Run() {
 // CHECK:STDOUT:   %complete_type.e68: <witness> = complete_type_witness %struct_type.a [concrete]
 // CHECK:STDOUT:   %pattern_type.e31: type = pattern_type %ptr [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.446: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.446: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.4d8: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%ptr) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.1cb: %T.as.DefaultOrUnformed.impl.Op.type.4d8 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %ptr, (%DefaultOrUnformed.impl_witness.446) [concrete]
@@ -107,7 +107,7 @@ fn Run() {
 // CHECK:STDOUT:   %Main.import_ref.465 = import_ref Main//a, loc5_8, unloaded
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/class/import_struct_cycle.carbon

@@ -43,10 +43,10 @@ fn Run() {
 // CHECK:STDOUT:   %struct_type.b: type = struct_type {.b: %ptr} [concrete]
 // CHECK:STDOUT:   %pattern_type.d79: type = pattern_type %struct_type.b [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.64d: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%struct_type.b) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.64d: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%struct_type.b) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.d8d: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%struct_type.b) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.654: %T.as.DefaultOrUnformed.impl.Op.type.d8d = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %struct_type.b, (%DefaultOrUnformed.impl_witness.64d) [concrete]
@@ -64,7 +64,7 @@ fn Run() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/class/method/method.carbon

@@ -127,7 +127,7 @@ fn CallGOnInitializingExpr() -> i32 {
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.3d0: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.cda: %T.as.DefaultOrUnformed.impl.Op.type.3d0 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %Class, (%DefaultOrUnformed.impl_witness.6ca) [concrete]
@@ -167,7 +167,7 @@ fn CallGOnInitializingExpr() -> i32 {
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/class/method/static_method.carbon

@@ -40,10 +40,10 @@ fn Run() -> i32 {
 // CHECK:STDOUT:   %Run: %Run.type = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.904: type = pattern_type %Class [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.3d0: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.cda: %T.as.DefaultOrUnformed.impl.Op.type.3d0 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %Class, (%DefaultOrUnformed.impl_witness.6ca) [concrete]
@@ -64,7 +64,7 @@ fn Run() -> i32 {
 // CHECK:STDOUT:   %Core.Int: %Int.type = import_ref Core//prelude/parts/int, Int, loaded [concrete = constants.%Int.generic]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/class/nested.carbon

@@ -80,13 +80,13 @@ fn F(a: Outer*) {
 // CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.52f: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Outer) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.52f: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Outer) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.8b8: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Outer) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.de4: %T.as.DefaultOrUnformed.impl.Op.type.8b8 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.83f: %DefaultOrUnformed.type = facet_value %Outer, (%DefaultOrUnformed.impl_witness.52f) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.specific_fn.a30: <specific function> = specific_function %T.as.DefaultOrUnformed.impl.Op.de4, @T.as.DefaultOrUnformed.impl.Op(%Outer) [concrete]
 // CHECK:STDOUT:   %pattern_type.86a: type = pattern_type %Inner [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.994: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Inner) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.994: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Inner) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.036: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Inner) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.da3: %T.as.DefaultOrUnformed.impl.Op.type.036 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.6ba: %DefaultOrUnformed.type = facet_value %Inner, (%DefaultOrUnformed.impl_witness.994) [concrete]
@@ -129,7 +129,7 @@ fn F(a: Outer*) {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT:   %Core.Copy: type = import_ref Core//prelude/parts/copy, Copy, loaded [concrete = constants.%Copy.type]
 // CHECK:STDOUT:   %Core.import_ref.203: @ptr.as.Copy.impl.%ptr.as.Copy.impl.Op.type (%ptr.as.Copy.impl.Op.type.2d4) = import_ref Core//prelude/parts/copy, loc{{\d+_\d+}}, loaded [symbolic = @ptr.as.Copy.impl.%ptr.as.Copy.impl.Op (constants.%ptr.as.Copy.impl.Op.74e)]

toolchain/check/testdata/class/nested_name.carbon

@@ -64,7 +64,7 @@ fn G(o: Outer) {
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.994: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Inner) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.994: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Inner) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.036: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Inner) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.da3: %T.as.DefaultOrUnformed.impl.Op.type.036 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %Inner, (%DefaultOrUnformed.impl_witness.994) [concrete]
@@ -89,7 +89,7 @@ fn G(o: Outer) {
 // CHECK:STDOUT:   %Copy.impl_witness_table.e76 = impl_witness_table (%Core.import_ref.18d), @Int.as.Copy.impl [concrete]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/class/self/raw_self_type.carbon

@@ -42,7 +42,7 @@ fn MemberNamedSelf.F(unused x: Self, unused y: r#Self) {}
 // CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.5ad: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%ptr.8e5) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.5ad: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%ptr.8e5) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.e77: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%ptr.8e5) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.d9e: %T.as.DefaultOrUnformed.impl.Op.type.e77 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %ptr.8e5, (%DefaultOrUnformed.impl_witness.5ad) [concrete]
@@ -78,7 +78,7 @@ fn MemberNamedSelf.F(unused x: Self, unused y: r#Self) {}
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Copy: type = import_ref Core//prelude/parts/copy, Copy, loaded [concrete = constants.%Copy.type]
 // CHECK:STDOUT:   %Core.import_ref.203: @ptr.as.Copy.impl.%ptr.as.Copy.impl.Op.type (%ptr.as.Copy.impl.Op.type.2d4) = import_ref Core//prelude/parts/copy, loc{{\d+_\d+}}, loaded [symbolic = @ptr.as.Copy.impl.%ptr.as.Copy.impl.Op (constants.%ptr.as.Copy.impl.Op.74e)]
 // CHECK:STDOUT:   %Copy.impl_witness_table.c3a = impl_witness_table (%Core.import_ref.203), @ptr.as.Copy.impl [concrete]

toolchain/check/testdata/class/self/self_type.carbon

@@ -50,7 +50,7 @@ fn Class.F[self: Self]() -> i32 {
 // CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6ca: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.3d0: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Class) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.cda: %T.as.DefaultOrUnformed.impl.Op.type.3d0 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %Class, (%DefaultOrUnformed.impl_witness.6ca) [concrete]
@@ -78,7 +78,7 @@ fn Class.F[self: Self]() -> i32 {
 // CHECK:STDOUT:   %Core.Int: %Int.type = import_ref Core//prelude/parts/int, Int, loaded [concrete = constants.%Int.generic]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Copy: type = import_ref Core//prelude/parts/copy, Copy, loaded [concrete = constants.%Copy.type]
 // CHECK:STDOUT:   %Core.import_ref.203: @ptr.as.Copy.impl.%ptr.as.Copy.impl.Op.type (%ptr.as.Copy.impl.Op.type.2d4) = import_ref Core//prelude/parts/copy, loc{{\d+_\d+}}, loaded [symbolic = @ptr.as.Copy.impl.%ptr.as.Copy.impl.Op (constants.%ptr.as.Copy.impl.Op.74e)]
 // CHECK:STDOUT:   %Copy.impl_witness_table.c3a = impl_witness_table (%Core.import_ref.203), @ptr.as.Copy.impl [concrete]

toolchain/check/testdata/eval/aggregates.carbon

@@ -483,10 +483,10 @@ fn G(N:! i32) {
 // CHECK:STDOUT: --- symbolic.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
 // CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
-// CHECK:STDOUT:   %ptr.e8f: type = ptr_type %T [symbolic]
-// CHECK:STDOUT:   %const: type = const_type %T [symbolic]
+// CHECK:STDOUT:   %ptr.e8f: type = ptr_type %T.67d [symbolic]
+// CHECK:STDOUT:   %const: type = const_type %T.67d [symbolic]
 // CHECK:STDOUT:   %tuple.type.24b: type = tuple_type (type, type) [concrete]
 // CHECK:STDOUT:   %tuple: %tuple.type.24b = tuple_value (%ptr.e8f, %const) [symbolic]
 // CHECK:STDOUT:   %tuple.type.3c8: type = tuple_type (%ptr.e8f, %const) [symbolic]
@@ -500,7 +500,7 @@ fn G(N:! i32) {
 // CHECK:STDOUT:   %.246: type = fn_type_with_self_type %DefaultOrUnformed.WithSelf.Op.type.0af, %DefaultOrUnformed.facet.9a0 [symbolic]
 // CHECK:STDOUT:   %impl.elem0.c6f: %.246 = impl_witness_access %DefaultOrUnformed.lookup_impl_witness.2ad, element0 [symbolic]
 // CHECK:STDOUT:   %specific_impl_fn.58b: <specific function> = specific_impl_function %impl.elem0.c6f, @DefaultOrUnformed.WithSelf.Op(%DefaultOrUnformed.facet.9a0) [symbolic]
-// CHECK:STDOUT:   %struct_type.a: type = struct_type {.a: %T} [symbolic]
+// CHECK:STDOUT:   %struct_type.a: type = struct_type {.a: %T.67d} [symbolic]
 // CHECK:STDOUT:   %require_complete.5d6: <witness> = require_complete_type %struct_type.a [symbolic]
 // CHECK:STDOUT:   %pattern_type.7b9: type = pattern_type %struct_type.a [symbolic]
 // CHECK:STDOUT:   %.d26: require_specific_def_type = require_specific_def @T.as.DefaultOrUnformed.impl(%struct_type.a) [symbolic]
@@ -511,7 +511,7 @@ fn G(N:! i32) {
 // CHECK:STDOUT:   %impl.elem0.e9c: %.9ac = impl_witness_access %DefaultOrUnformed.lookup_impl_witness.169, element0 [symbolic]
 // CHECK:STDOUT:   %specific_impl_fn.cf6: <specific function> = specific_impl_function %impl.elem0.e9c, @DefaultOrUnformed.WithSelf.Op(%DefaultOrUnformed.facet.ca5) [symbolic]
 // CHECK:STDOUT:   %int_5: Core.IntLiteral = int_value 5 [concrete]
-// CHECK:STDOUT:   %array_type.742: type = array_type %int_5, %T [symbolic]
+// CHECK:STDOUT:   %array_type.742: type = array_type %int_5, %T.67d [symbolic]
 // CHECK:STDOUT:   %require_complete.345: <witness> = require_complete_type %array_type.742 [symbolic]
 // CHECK:STDOUT:   %pattern_type.d52: type = pattern_type %array_type.742 [symbolic]
 // CHECK:STDOUT:   %.617: require_specific_def_type = require_specific_def @T.as.DefaultOrUnformed.impl(%array_type.742) [symbolic]
@@ -597,7 +597,7 @@ fn G(N:! i32) {
 // CHECK:STDOUT:   %.loc6_30.4: type = fn_type_with_self_type %DefaultOrUnformed.WithSelf.Op.type.loc6, %DefaultOrUnformed.facet.loc6_30.2 [symbolic = %.loc6_30.4 (constants.%.246)]
 // CHECK:STDOUT:   %impl.elem0.loc6_30.2: @F.%.loc6_30.4 (%.246) = impl_witness_access %DefaultOrUnformed.lookup_impl_witness.loc6, element0 [symbolic = %impl.elem0.loc6_30.2 (constants.%impl.elem0.c6f)]
 // CHECK:STDOUT:   %specific_impl_fn.loc6_30.2: <specific function> = specific_impl_function %impl.elem0.loc6_30.2, @DefaultOrUnformed.WithSelf.Op(%DefaultOrUnformed.facet.loc6_30.2) [symbolic = %specific_impl_fn.loc6_30.2 (constants.%specific_impl_fn.58b)]
-// CHECK:STDOUT:   %struct_type.a.loc7_23.2: type = struct_type {.a: @F.%T.loc4_6.1 (%T)} [symbolic = %struct_type.a.loc7_23.2 (constants.%struct_type.a)]
+// CHECK:STDOUT:   %struct_type.a.loc7_23.2: type = struct_type {.a: @F.%T.loc4_6.1 (%T.67d)} [symbolic = %struct_type.a.loc7_23.2 (constants.%struct_type.a)]
 // CHECK:STDOUT:   %require_complete.loc7: <witness> = require_complete_type %struct_type.a.loc7_23.2 [symbolic = %require_complete.loc7 (constants.%require_complete.5d6)]
 // CHECK:STDOUT:   %pattern_type.loc7: type = pattern_type %struct_type.a.loc7_23.2 [symbolic = %pattern_type.loc7 (constants.%pattern_type.7b9)]
 // CHECK:STDOUT:   %.loc7_24.3: require_specific_def_type = require_specific_def @T.as.DefaultOrUnformed.impl(%struct_type.a.loc7_23.2) [symbolic = %.loc7_24.3 (constants.%.d26)]
@@ -653,9 +653,9 @@ fn G(N:! i32) {
 // CHECK:STDOUT:     %DefaultOrUnformed.WithSelf.Op.call.loc6: init @F.%tuple.type (%tuple.type.3c8) to %.loc6_3.1 = call %specific_impl_fn.loc6_30.1()
 // CHECK:STDOUT:     assign %u.var, %DefaultOrUnformed.WithSelf.Op.call.loc6
 // CHECK:STDOUT:     %.loc6_29.1: type = splice_block %.loc6_29.3 [symbolic = %tuple.type (constants.%tuple.type.3c8)] {
-// CHECK:STDOUT:       %T.ref.loc6_18: type = name_ref T, %T.loc4_6.2 [symbolic = %T.loc4_6.1 (constants.%T)]
+// CHECK:STDOUT:       %T.ref.loc6_18: type = name_ref T, %T.loc4_6.2 [symbolic = %T.loc4_6.1 (constants.%T.67d)]
 // CHECK:STDOUT:       %ptr.loc6_19.1: type = ptr_type %T.ref.loc6_18 [symbolic = %ptr.loc6_19.2 (constants.%ptr.e8f)]
-// CHECK:STDOUT:       %T.ref.loc6_28: type = name_ref T, %T.loc4_6.2 [symbolic = %T.loc4_6.1 (constants.%T)]
+// CHECK:STDOUT:       %T.ref.loc6_28: type = name_ref T, %T.loc4_6.2 [symbolic = %T.loc4_6.1 (constants.%T.67d)]
 // CHECK:STDOUT:       %const.loc6_22.1: type = const_type %T.ref.loc6_28 [symbolic = %const.loc6_22.2 (constants.%const)]
 // CHECK:STDOUT:       %.loc6_29.2: %tuple.type.24b = tuple_literal (%ptr.loc6_19.1, %const.loc6_22.1) [symbolic = %tuple (constants.%tuple)]
 // CHECK:STDOUT:       %.loc6_29.3: type = converted %.loc6_29.2, constants.%tuple.type.3c8 [symbolic = %tuple.type (constants.%tuple.type.3c8)]
@@ -675,8 +675,8 @@ fn G(N:! i32) {
 // CHECK:STDOUT:     %DefaultOrUnformed.WithSelf.Op.call.loc7: init @F.%struct_type.a.loc7_23.2 (%struct_type.a) = call %specific_impl_fn.loc7_24.1()
 // CHECK:STDOUT:     assign %v.var, %DefaultOrUnformed.WithSelf.Op.call.loc7
 // CHECK:STDOUT:     %.loc7_23: type = splice_block %struct_type.a.loc7_23.1 [symbolic = %struct_type.a.loc7_23.2 (constants.%struct_type.a)] {
-// CHECK:STDOUT:       %T.ref.loc7: type = name_ref T, %T.loc4_6.2 [symbolic = %T.loc4_6.1 (constants.%T)]
-// CHECK:STDOUT:       %struct_type.a.loc7_23.1: type = struct_type {.a: @F.%T.loc4_6.1 (%T)} [symbolic = %struct_type.a.loc7_23.2 (constants.%struct_type.a)]
+// CHECK:STDOUT:       %T.ref.loc7: type = name_ref T, %T.loc4_6.2 [symbolic = %T.loc4_6.1 (constants.%T.67d)]
+// CHECK:STDOUT:       %struct_type.a.loc7_23.1: type = struct_type {.a: @F.%T.loc4_6.1 (%T.67d)} [symbolic = %struct_type.a.loc7_23.2 (constants.%struct_type.a)]
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %v: ref @F.%struct_type.a.loc7_23.2 (%struct_type.a) = ref_binding v, %v.var
 // CHECK:STDOUT:     name_binding_decl {
@@ -694,7 +694,7 @@ fn G(N:! i32) {
 // CHECK:STDOUT:     %DefaultOrUnformed.WithSelf.Op.call.loc8: init @F.%array_type.loc8_27.2 (%array_type.742) to %.loc8_3.1 = call %specific_impl_fn.loc8_28.1()
 // CHECK:STDOUT:     assign %w.var, %DefaultOrUnformed.WithSelf.Op.call.loc8
 // CHECK:STDOUT:     %.loc8_27: type = splice_block %array_type.loc8_27.1 [symbolic = %array_type.loc8_27.2 (constants.%array_type.742)] {
-// CHECK:STDOUT:       %T.ref.loc8: type = name_ref T, %T.loc4_6.2 [symbolic = %T.loc4_6.1 (constants.%T)]
+// CHECK:STDOUT:       %T.ref.loc8: type = name_ref T, %T.loc4_6.2 [symbolic = %T.loc4_6.1 (constants.%T.67d)]
 // CHECK:STDOUT:       %int_5: Core.IntLiteral = int_value 5 [concrete = constants.%int_5]
 // CHECK:STDOUT:       %array_type.loc8_27.1: type = array_type %int_5, %T.ref.loc8 [symbolic = %array_type.loc8_27.2 (constants.%array_type.742)]
 // CHECK:STDOUT:     }
@@ -780,8 +780,8 @@ fn G(N:! i32) {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @F(constants.%T) {
-// CHECK:STDOUT:   %T.loc4_6.1 => constants.%T
+// CHECK:STDOUT: specific @F(constants.%T.67d) {
+// CHECK:STDOUT:   %T.loc4_6.1 => constants.%T.67d
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: specific @G(constants.%N.5de) {

toolchain/check/testdata/function/builtin/call.carbon

@@ -70,10 +70,10 @@ fn RuntimeCall(a: i32, b: i32) -> i32 {
 // CHECK:STDOUT:   %array_type: type = array_type %int_3.1ba, %i32 [concrete]
 // CHECK:STDOUT:   %pattern_type.5d8: type = pattern_type %array_type [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.d11: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%array_type) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.d11: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%array_type) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.576: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%array_type) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.9c0: %T.as.DefaultOrUnformed.impl.Op.type.576 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %array_type, (%DefaultOrUnformed.impl_witness.d11) [concrete]
@@ -98,7 +98,7 @@ fn RuntimeCall(a: i32, b: i32) -> i32 {
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.ea2 = impl_witness_table (%Core.import_ref.0bc), @Int.as.ImplicitAs.impl [concrete]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/function/builtin/method.carbon

@@ -99,10 +99,10 @@ var arr: array(i32, (1 as i32).(I.F)(2));
 // CHECK:STDOUT:   %array_type: type = array_type %int_3.1ba, %i32 [concrete]
 // CHECK:STDOUT:   %pattern_type.5d8: type = pattern_type %array_type [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.d11: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%array_type) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.d11: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%array_type) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.576: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%array_type) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.9c0: %T.as.DefaultOrUnformed.impl.Op.type.576 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %array_type, (%DefaultOrUnformed.impl_witness.d11) [concrete]
@@ -129,7 +129,7 @@ var arr: array(i32, (1 as i32).(I.F)(2));
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.ea2 = impl_witness_table (%Core.import_ref.0bc), @Int.as.ImplicitAs.impl [concrete]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/function/call/ref.carbon

@@ -191,10 +191,10 @@ fn G() {
 // CHECK:STDOUT:   %G.type: type = fn_type @G [concrete]
 // CHECK:STDOUT:   %G: %G.type = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6fd: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%C) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6fd: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%C) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %C, (%DefaultOrUnformed.impl_witness.6fd) [concrete]
 // CHECK:STDOUT:   %Destroy.Op.type: type = fn_type @Destroy.Op [concrete]
 // CHECK:STDOUT:   %Destroy.Op: %Destroy.Op.type = struct_value () [concrete]
@@ -202,7 +202,7 @@ fn G() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/function/generic/resolve_used.carbon

@@ -56,8 +56,8 @@ fn CallNegative() {
 // CHECK:STDOUT:   %require_complete.901: <witness> = require_complete_type %Int [symbolic]
 // CHECK:STDOUT:   %pattern_type.764: type = pattern_type %Int [symbolic]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
 // CHECK:STDOUT:   %.4a9: require_specific_def_type = require_specific_def @T.as.DefaultOrUnformed.impl(%Int) [symbolic]
 // CHECK:STDOUT:   %DefaultOrUnformed.lookup_impl_witness: <witness> = lookup_impl_witness %Int, @DefaultOrUnformed [symbolic]
@@ -79,7 +79,7 @@ fn CallNegative() {
 // CHECK:STDOUT:   %ErrorIfNIsZero.specific_fn: <specific function> = specific_function %ErrorIfNIsZero, @ErrorIfNIsZero(%int_0) [concrete]
 // CHECK:STDOUT:   %i0: type = class_type @Int, @Int(%int_0) [concrete]
 // CHECK:STDOUT:   %pattern_type.47b: type = pattern_type %i0 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.879: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%i0) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.879: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%i0) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.7ec: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%i0) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.5b7: %T.as.DefaultOrUnformed.impl.Op.type.7ec = struct_value () [concrete]
 // CHECK:STDOUT:   %.d6a: require_specific_def_type = require_specific_def @T.as.DefaultOrUnformed.impl(%i0) [concrete]
@@ -108,7 +108,7 @@ fn CallNegative() {
 // CHECK:STDOUT:   %Core.Int: %Int.type = import_ref Core//prelude/parts/int, Int, loaded [concrete = constants.%Int.generic]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/function/generic/type_param.carbon

@@ -23,16 +23,16 @@ fn F(T:! type) {
 // CHECK:STDOUT:   %type: type = facet_type <type> [concrete]
 // CHECK:STDOUT:   %.Self: %type = symbolic_binding .Self [symbolic_self]
 // CHECK:STDOUT:   %pattern_type.98f: type = pattern_type type [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
 // CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
 // CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
-// CHECK:STDOUT:   %ptr: type = ptr_type %T [symbolic]
+// CHECK:STDOUT:   %ptr: type = ptr_type %T.67d [symbolic]
 // CHECK:STDOUT:   %require_complete.ef1: <witness> = require_complete_type %ptr [symbolic]
 // CHECK:STDOUT:   %pattern_type.4f4: type = pattern_type %ptr [symbolic]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %require_complete.944: <witness> = require_complete_type %T [symbolic]
-// CHECK:STDOUT:   %pattern_type.51d: type = pattern_type %T [symbolic]
+// CHECK:STDOUT:   %require_complete.944: <witness> = require_complete_type %T.67d [symbolic]
+// CHECK:STDOUT:   %pattern_type.51d: type = pattern_type %T.67d [symbolic]
 // CHECK:STDOUT:   %.713: require_specific_def_type = require_specific_def @T.as.DefaultOrUnformed.impl(%ptr) [symbolic]
 // CHECK:STDOUT:   %DefaultOrUnformed.lookup_impl_witness: <witness> = lookup_impl_witness %ptr, @DefaultOrUnformed [symbolic]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %ptr, (%DefaultOrUnformed.lookup_impl_witness) [symbolic]
@@ -73,12 +73,12 @@ fn F(T:! type) {
 // CHECK:STDOUT:       %.Self: %type = symbolic_binding .Self [symbolic_self = constants.%.Self]
 // CHECK:STDOUT:       %.loc15_10.2: type = type_literal type [concrete = type]
 // CHECK:STDOUT:     }
-// CHECK:STDOUT:     %T.loc15_6.2: type = symbolic_binding T, 0 [symbolic = %T.loc15_6.1 (constants.%T)]
+// CHECK:STDOUT:     %T.loc15_6.2: type = symbolic_binding T, 0 [symbolic = %T.loc15_6.1 (constants.%T.67d)]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: generic fn @F(%T.loc15_6.2: type) {
-// CHECK:STDOUT:   %T.loc15_6.1: type = symbolic_binding T, 0 [symbolic = %T.loc15_6.1 (constants.%T)]
+// CHECK:STDOUT:   %T.loc15_6.1: type = symbolic_binding T, 0 [symbolic = %T.loc15_6.1 (constants.%T.67d)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %ptr.loc16_11.2: type = ptr_type %T.loc15_6.1 [symbolic = %ptr.loc16_11.2 (constants.%ptr)]
@@ -116,7 +116,7 @@ fn F(T:! type) {
 // CHECK:STDOUT:     %DefaultOrUnformed.WithSelf.Op.call: init @F.%ptr.loc16_11.2 (%ptr) = call %specific_impl_fn.loc16_12.1()
 // CHECK:STDOUT:     assign %p.var, %DefaultOrUnformed.WithSelf.Op.call
 // CHECK:STDOUT:     %.loc16_11: type = splice_block %ptr.loc16_11.1 [symbolic = %ptr.loc16_11.2 (constants.%ptr)] {
-// CHECK:STDOUT:       %T.ref.loc16: type = name_ref T, %T.loc15_6.2 [symbolic = %T.loc15_6.1 (constants.%T)]
+// CHECK:STDOUT:       %T.ref.loc16: type = name_ref T, %T.loc15_6.2 [symbolic = %T.loc15_6.1 (constants.%T.67d)]
 // CHECK:STDOUT:       %ptr.loc16_11.1: type = ptr_type %T.ref.loc16 [symbolic = %ptr.loc16_11.2 (constants.%ptr)]
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %p: ref @F.%ptr.loc16_11.2 (%ptr) = ref_binding p, %p.var
@@ -125,10 +125,10 @@ fn F(T:! type) {
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %p.ref: ref @F.%ptr.loc16_11.2 (%ptr) = name_ref p, %p
 // CHECK:STDOUT:     %.loc17_22: @F.%ptr.loc16_11.2 (%ptr) = acquire_value %p.ref
-// CHECK:STDOUT:     %.loc17_21.1: ref @F.%T.loc15_6.1 (%T) = deref %.loc17_22
-// CHECK:STDOUT:     %T.ref.loc17: type = name_ref T, %T.loc15_6.2 [symbolic = %T.loc15_6.1 (constants.%T)]
-// CHECK:STDOUT:     %.loc17_21.2: @F.%T.loc15_6.1 (%T) = acquire_value %.loc17_21.1
-// CHECK:STDOUT:     %n: @F.%T.loc15_6.1 (%T) = value_binding n, %.loc17_21.2
+// CHECK:STDOUT:     %.loc17_21.1: ref @F.%T.loc15_6.1 (%T.67d) = deref %.loc17_22
+// CHECK:STDOUT:     %T.ref.loc17: type = name_ref T, %T.loc15_6.2 [symbolic = %T.loc15_6.1 (constants.%T.67d)]
+// CHECK:STDOUT:     %.loc17_21.2: @F.%T.loc15_6.1 (%T.67d) = acquire_value %.loc17_21.1
+// CHECK:STDOUT:     %n: @F.%T.loc15_6.1 (%T.67d) = value_binding n, %.loc17_21.2
 // CHECK:STDOUT:     %impl.elem0.loc16_3.1: @F.%.loc16_3 (%.c3f) = impl_witness_access constants.%Destroy.lookup_impl_witness, element0 [symbolic = %impl.elem0.loc16_3.2 (constants.%impl.elem0.b55)]
 // CHECK:STDOUT:     %bound_method.loc16_3.1: <bound method> = bound_method %p.var, %impl.elem0.loc16_3.1
 // CHECK:STDOUT:     %specific_impl_fn.loc16_3.1: <specific function> = specific_impl_function %impl.elem0.loc16_3.1, @Destroy.WithSelf.Op(constants.%Destroy.facet) [symbolic = %specific_impl_fn.loc16_3.2 (constants.%specific_impl_fn.5c7)]
@@ -138,7 +138,7 @@ fn F(T:! type) {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @F(constants.%T) {
-// CHECK:STDOUT:   %T.loc15_6.1 => constants.%T
+// CHECK:STDOUT: specific @F(constants.%T.67d) {
+// CHECK:STDOUT:   %T.loc15_6.1 => constants.%T.67d
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/global/basics.carbon

@@ -60,16 +60,16 @@ var a: A = Make();
 // CHECK:STDOUT:   %empty_struct: %empty_struct_type = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.a96: type = pattern_type %empty_struct_type [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.3f9: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%empty_struct_type) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.3f9: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%empty_struct_type) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %empty_struct_type, (%DefaultOrUnformed.impl_witness.3f9) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/interface/as_type_of_type.carbon

@@ -39,8 +39,8 @@ fn F(T:! Empty) {
 // CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
 // CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
-// CHECK:STDOUT:   %T.binding.as_type: type = symbolic_binding_type T, 0, %T.0c3 [symbolic]
-// CHECK:STDOUT:   %ptr: type = ptr_type %T.binding.as_type [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.e23: type = symbolic_binding_type T, 0, %T.0c3 [symbolic]
+// CHECK:STDOUT:   %ptr: type = ptr_type %T.binding.as_type.e23 [symbolic]
 // CHECK:STDOUT:   %require_complete.315: <witness> = require_complete_type %ptr [symbolic]
 // CHECK:STDOUT:   %pattern_type.fd9: type = pattern_type %ptr [symbolic]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
@@ -127,7 +127,7 @@ fn F(T:! Empty) {
 // CHECK:STDOUT:   %T.loc21_6.1: %Empty.type = symbolic_binding T, 0 [symbolic = %T.loc21_6.1 (constants.%T.0c3)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %T.binding.as_type: type = symbolic_binding_type T, 0, %T.loc21_6.1 [symbolic = %T.binding.as_type (constants.%T.binding.as_type)]
+// CHECK:STDOUT:   %T.binding.as_type: type = symbolic_binding_type T, 0, %T.loc21_6.1 [symbolic = %T.binding.as_type (constants.%T.binding.as_type.e23)]
 // CHECK:STDOUT:   %ptr.loc22_18.2: type = ptr_type %T.binding.as_type [symbolic = %ptr.loc22_18.2 (constants.%ptr)]
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type %ptr.loc22_18.2 [symbolic = %require_complete (constants.%require_complete.315)]
 // CHECK:STDOUT:   %pattern_type: type = pattern_type %ptr.loc22_18.2 [symbolic = %pattern_type (constants.%pattern_type.fd9)]
@@ -162,8 +162,8 @@ fn F(T:! Empty) {
 // CHECK:STDOUT:     assign %x.var, %DefaultOrUnformed.WithSelf.Op.call
 // CHECK:STDOUT:     %.loc22_18.1: type = splice_block %ptr.loc22_18.1 [symbolic = %ptr.loc22_18.2 (constants.%ptr)] {
 // CHECK:STDOUT:       %T.ref: %Empty.type = name_ref T, %T.loc21_6.2 [symbolic = %T.loc21_6.1 (constants.%T.0c3)]
-// CHECK:STDOUT:       %T.as_type: type = facet_access_type %T.ref [symbolic = %T.binding.as_type (constants.%T.binding.as_type)]
-// CHECK:STDOUT:       %.loc22_18.2: type = converted %T.ref, %T.as_type [symbolic = %T.binding.as_type (constants.%T.binding.as_type)]
+// CHECK:STDOUT:       %T.as_type: type = facet_access_type %T.ref [symbolic = %T.binding.as_type (constants.%T.binding.as_type.e23)]
+// CHECK:STDOUT:       %.loc22_18.2: type = converted %T.ref, %T.as_type [symbolic = %T.binding.as_type (constants.%T.binding.as_type.e23)]
 // CHECK:STDOUT:       %ptr.loc22_18.1: type = ptr_type %.loc22_18.2 [symbolic = %ptr.loc22_18.2 (constants.%ptr)]
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %x: ref @F.%ptr.loc22_18.2 (%ptr) = ref_binding x, %x.var

toolchain/check/testdata/interface/generic_method.carbon

@@ -157,7 +157,7 @@ fn CallIndirect() {
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.263: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%Z) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.263: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%Z) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.b84: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%Z) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.4f1: %T.as.DefaultOrUnformed.impl.Op.type.b84 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %Z, (%DefaultOrUnformed.impl_witness.263) [concrete]
@@ -231,7 +231,7 @@ fn CallIndirect() {
 // CHECK:STDOUT:   %Copy.impl_witness_table.c3a = impl_witness_table (%Core.import_ref.203), @ptr.as.Copy.impl [concrete]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/interface/import.carbon

@@ -74,10 +74,10 @@ var f: ForwardDeclared* = &f_ref.f;
 // CHECK:STDOUT:   %struct_type.f: type = struct_type {.f: %ForwardDeclared.type} [concrete]
 // CHECK:STDOUT:   %pattern_type.afe: type = pattern_type %struct_type.f [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.527: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%struct_type.f) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.527: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%struct_type.f) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.8d4: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%struct_type.f) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.100: %T.as.DefaultOrUnformed.impl.Op.type.8d4 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %struct_type.f, (%DefaultOrUnformed.impl_witness.527) [concrete]
@@ -92,7 +92,7 @@ var f: ForwardDeclared* = &f_ref.f;
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/interop/cpp/builtins.carbon

@@ -511,11 +511,16 @@ fn F() {
 // CHECK:STDOUT:   %unsigned_int: type = class_type @unsigned_int [concrete]
 // CHECK:STDOUT:   %pattern_type.5ec: type = pattern_type %unsigned_int [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.4c4: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%unsigned_int) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %unsigned_int, (%DefaultOrUnformed.impl_witness.4c4) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %unsigned_int.Op.type: type = fn_type @unsigned_int.Op [concrete]
+// CHECK:STDOUT:   %unsigned_int.Op: %unsigned_int.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.bd1: <witness> = custom_witness (%unsigned_int.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.6ad: %Default.type = facet_value %unsigned_int, (%custom_witness.bd1) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.099: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.6ad) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %unsigned_int, (%DefaultOrUnformed.impl_witness.099) [concrete]
 // CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [concrete]
 // CHECK:STDOUT:   %u32: type = class_type @UInt, @UInt(%int_32) [concrete]
 // CHECK:STDOUT:   %pattern_type.4a9: type = pattern_type %u32 [concrete]
@@ -533,8 +538,8 @@ fn F() {
 // CHECK:STDOUT:     import Cpp//...
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %unsigned_int.decl: type = class_decl @unsigned_int [concrete = constants.%unsigned_int] {} {}
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %unsigned_int.foo.cpp_overload_set.value: %unsigned_int.foo.cpp_overload_set.type = cpp_overload_set_value @unsigned_int.foo.cpp_overload_set [concrete = constants.%unsigned_int.foo.cpp_overload_set.value]
 // CHECK:STDOUT:   %unsigned_int.foo.decl: %unsigned_int.foo.type = fn_decl @unsigned_int.foo [concrete = constants.%unsigned_int.foo] {
 // CHECK:STDOUT:     %self.param_patt: %pattern_type.5ec = ref_param_pattern [concrete]
@@ -555,14 +560,14 @@ fn F() {
 // CHECK:STDOUT:     %unsigned_int.var_patt: %pattern_type.5ec = var_pattern %unsigned_int.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %unsigned_int.var: ref %unsigned_int = var %unsigned_int.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%unsigned_int, (constants.%DefaultOrUnformed.impl_witness.4c4) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%unsigned_int, (constants.%DefaultOrUnformed.impl_witness.099) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc12_38.1: %DefaultOrUnformed.type = converted constants.%unsigned_int, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc12_38.1 [concrete = constants.%unsigned_int]
 // CHECK:STDOUT:   %.loc12_38.2: type = converted %.loc12_38.1, %as_type [concrete = constants.%unsigned_int]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc12_3: ref %unsigned_int = splice_block %unsigned_int.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %unsigned_int to %.loc12_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %unsigned_int.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %unsigned_int to %.loc12_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %unsigned_int.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc12_25: type = splice_block %unsigned_int.ref.loc12 [concrete = constants.%unsigned_int] {
 // CHECK:STDOUT:     %Cpp.ref: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %unsigned_int.ref.loc12: type = name_ref unsigned_int, imports.%unsigned_int.decl [concrete = constants.%unsigned_int]

toolchain/check/testdata/interop/cpp/class/constructor.carbon

@@ -21,6 +21,10 @@ class C {
   C();
 };
 
+struct NoDefault {
+  NoDefault(int);
+};
+
 // --- import_default.carbon
 
 library "[[@TEST_NAME]]";
@@ -33,6 +37,59 @@ fn F() {
   //@dump-sem-ir-end
 }
 
+// --- implicit_default.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp library "default.h";
+
+fn F() {
+  //@dump-sem-ir-begin
+  var unused c: Cpp.C;
+  //@dump-sem-ir-end
+}
+
+fn G(T:! Core.Default & Core.Destroy) {
+  var unused x: T;
+}
+
+fn CallG() {
+  G(Cpp.C);
+}
+
+// --- todo_fail_no_default_decl.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp library "default.h";
+
+fn F() {
+  // TODO: This should fail, but currently does not because the min_prelude
+  // version of UnformedInit is currently implemented by every type.
+  var unused x: Cpp.NoDefault;
+}
+
+// --- fail_no_default.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp library "default.h";
+
+fn G(T:! Core.Default & Core.Destroy) {
+  var unused x: T;
+}
+
+fn CallG() {
+  // CHECK:STDERR: fail_no_default.carbon:[[@LINE+7]]:3: error: cannot convert type `NoDefault` into type implementing `Core.Default & Core.Destroy` [ConversionFailureTypeToFacet]
+  // CHECK:STDERR:   G(Cpp.NoDefault);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_no_default.carbon:[[@LINE-8]]:6: note: initializing generic parameter `T` declared here [InitializingGenericParam]
+  // CHECK:STDERR: fn G(T:! Core.Default & Core.Destroy) {
+  // CHECK:STDERR:      ^
+  // CHECK:STDERR:
+  G(Cpp.NoDefault);
+}
+
 // ============================================================================
 // Non default constructor
 // ============================================================================
@@ -308,6 +365,62 @@ fn F() {
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- implicit_default.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
+// CHECK:STDOUT:   %C: type = class_type @C [concrete]
+// CHECK:STDOUT:   %pattern_type.217: type = pattern_type %C [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %C.Op.type: type = fn_type @C.Op [concrete]
+// CHECK:STDOUT:   %C.Op: %C.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.a0a: <witness> = custom_witness (%C.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.fdc: %Default.type = facet_value %C, (%custom_witness.a0a) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.2aa: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.fdc) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.898: %DefaultOrUnformed.type = facet_value %C, (%DefaultOrUnformed.impl_witness.2aa) [concrete]
+// CHECK:STDOUT:   %C.cpp_destructor.type: type = fn_type @C.cpp_destructor [concrete]
+// CHECK:STDOUT:   %C.cpp_destructor: %C.cpp_destructor.type = struct_value () [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Cpp: <namespace> = namespace file.%Cpp.import_cpp, [concrete] {
+// CHECK:STDOUT:     .C = %C.decl
+// CHECK:STDOUT:     import Cpp//...
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %C.decl: type = class_decl @C [concrete = constants.%C] {} {}
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @F() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %c.patt: %pattern_type.217 = ref_binding_pattern c [concrete]
+// CHECK:STDOUT:     %c.var_patt: %pattern_type.217 = var_pattern %c.patt [concrete]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %c.var: ref %C = var %c.var_patt
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%C, (constants.%DefaultOrUnformed.impl_witness.2aa) [concrete = constants.%DefaultOrUnformed.facet.898]
+// CHECK:STDOUT:   %.loc8_22.1: %DefaultOrUnformed.type = converted constants.%C, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet.898]
+// CHECK:STDOUT:   %as_type: type = facet_access_type %.loc8_22.1 [concrete = constants.%C]
+// CHECK:STDOUT:   %.loc8_22.2: type = converted %.loc8_22.1, %as_type [concrete = constants.%C]
+// CHECK:STDOUT:   <elided>
+// CHECK:STDOUT:   %.loc8_3: ref %C = splice_block %c.var {}
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %C to %.loc8_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %c.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %.loc8_20: type = splice_block %C.ref [concrete = constants.%C] {
+// CHECK:STDOUT:     %Cpp.ref: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
+// CHECK:STDOUT:     %C.ref: type = name_ref C, imports.%C.decl [concrete = constants.%C]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %c: ref %C = ref_binding c, %c.var
+// CHECK:STDOUT:   %C.cpp_destructor.bound: <bound method> = bound_method %c.var, constants.%C.cpp_destructor
+// CHECK:STDOUT:   %C.cpp_destructor.call: init %empty_tuple.type = call %C.cpp_destructor.bound(%c.var)
+// CHECK:STDOUT:   <elided>
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: --- import_non_default.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {

toolchain/check/testdata/interop/cpp/function/class.carbon

@@ -653,11 +653,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk.type: type = fn_type @foo__carbon_thunk [concrete]
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6df: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%C) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %C, (%DefaultOrUnformed.impl_witness.6df) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %C.Op.type: type = fn_type @C.Op [concrete]
+// CHECK:STDOUT:   %C.Op: %C.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.cb7: <witness> = custom_witness (%C.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.0fd: %Default.type = facet_value %C, (%custom_witness.cb7) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.5a3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.0fd) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %C, (%DefaultOrUnformed.impl_witness.5a3) [concrete]
 // CHECK:STDOUT:   %C.cpp_destructor.type: type = fn_type @C.cpp_destructor [concrete]
 // CHECK:STDOUT:   %C.cpp_destructor: %C.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -679,8 +684,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%c.param: %C) {
@@ -696,14 +701,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.69f = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %C = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%C, (constants.%DefaultOrUnformed.impl_witness.6df) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%C, (constants.%DefaultOrUnformed.impl_witness.5a3) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc10_24.1: %DefaultOrUnformed.type = converted constants.%C, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc10_24.1 [concrete = constants.%C]
 // CHECK:STDOUT:   %.loc10_24.2: type = converted %.loc10_24.1, %as_type [concrete = constants.%C]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc10_3: ref %C = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %C to %.loc10_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %C to %.loc10_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc10_22: type = splice_block %C.ref.loc10 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc10: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -775,11 +780,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.cff: type = pattern_type %O [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.938: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%O) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.938) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %O.Op.type: type = fn_type @O.Op [concrete]
+// CHECK:STDOUT:   %O.Op: %O.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.8f6: <witness> = custom_witness (%O.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.d7b: %Default.type = facet_value %O, (%custom_witness.8f6) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.e05: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.d7b) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.e05) [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor.type: type = fn_type @O.cpp_destructor [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor: %O.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -797,8 +807,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%c.param: %C) {
@@ -814,14 +824,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.cff = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %O = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.938) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.e05) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc9_22.1: %DefaultOrUnformed.type = converted constants.%O, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc9_22.1 [concrete = constants.%O]
 // CHECK:STDOUT:   %.loc9_22.2: type = converted %.loc9_22.1, %as_type [concrete = constants.%O]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc9_3: ref %O = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc9_20: type = splice_block %O.ref.loc9 [concrete = constants.%O] {
 // CHECK:STDOUT:     %Cpp.ref.loc9: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %O.ref.loc9: type = name_ref O, imports.%O.decl [concrete = constants.%O]

toolchain/check/testdata/interop/cpp/function/reference.carbon

@@ -381,18 +381,27 @@ fn F() {
 // CHECK:STDOUT:   %S: type = class_type @S [concrete]
 // CHECK:STDOUT:   %pattern_type.7da: type = pattern_type %S [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6b7: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%S) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.d8f: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.6b7) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %S.Op.type: type = fn_type @S.Op [concrete]
+// CHECK:STDOUT:   %S.Op: %S.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.4cd: <witness> = custom_witness (%S.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.889: %Default.type = facet_value %S, (%custom_witness.4cd) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a91: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.889) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.b0b: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.a91) [concrete]
 // CHECK:STDOUT:   %TakesLValue.cpp_overload_set.type: type = cpp_overload_set_type @TakesLValue.cpp_overload_set [concrete]
 // CHECK:STDOUT:   %TakesLValue.cpp_overload_set.value: %TakesLValue.cpp_overload_set.type = cpp_overload_set_value @TakesLValue.cpp_overload_set [concrete]
 // CHECK:STDOUT:   %const: type = const_type %S [concrete]
 // CHECK:STDOUT:   %T.e15: type = class_type @T [concrete]
 // CHECK:STDOUT:   %pattern_type.e6b: type = pattern_type %T.e15 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a11: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%T.e15) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.5fe: %DefaultOrUnformed.type = facet_value %T.e15, (%DefaultOrUnformed.impl_witness.a11) [concrete]
+// CHECK:STDOUT:   %T.Op.type: type = fn_type @T.Op [concrete]
+// CHECK:STDOUT:   %T.Op: %T.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.3b9: <witness> = custom_witness (%T.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.2fe: %Default.type = facet_value %T.e15, (%custom_witness.3b9) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.1bd: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.2fe) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.ac4: %DefaultOrUnformed.type = facet_value %T.e15, (%DefaultOrUnformed.impl_witness.1bd) [concrete]
 // CHECK:STDOUT:   %S.cpp_destructor.type: type = fn_type @S.cpp_destructor [concrete]
 // CHECK:STDOUT:   %S.cpp_destructor: %S.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT:   %T.cpp_destructor.type: type = fn_type @T.cpp_destructor [concrete]
@@ -407,8 +416,8 @@ fn F() {
 // CHECK:STDOUT:     import Cpp//...
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %S.decl: type = class_decl @S [concrete = constants.%S] {} {}
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %TakesLValue.cpp_overload_set.value: %TakesLValue.cpp_overload_set.type = cpp_overload_set_value @TakesLValue.cpp_overload_set [concrete = constants.%TakesLValue.cpp_overload_set.value]
 // CHECK:STDOUT:   %T.decl: type = class_decl @T [concrete = constants.%T.e15] {} {}
 // CHECK:STDOUT: }
@@ -420,14 +429,14 @@ fn F() {
 // CHECK:STDOUT:     %v.var_patt: %pattern_type.7da = var_pattern %v.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %v.var: ref %S = var %v.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.6b7) [concrete = constants.%DefaultOrUnformed.facet.d8f]
-// CHECK:STDOUT:   %.loc8_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.d8f]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.a91) [concrete = constants.%DefaultOrUnformed.facet.b0b]
+// CHECK:STDOUT:   %.loc8_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.b0b]
 // CHECK:STDOUT:   %as_type.loc8: type = facet_access_type %.loc8_15.1 [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_15.2: type = converted %.loc8_15.1, %as_type.loc8 [concrete = constants.%S]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc8_3: ref %S = splice_block %v.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc8: init %S to %.loc8_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.1()
-// CHECK:STDOUT:   assign %v.var, %T.as.DefaultOrUnformed.impl.Op.call.loc8
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8: init %S to %.loc8_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.1()
+// CHECK:STDOUT:   assign %v.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref.loc8 [concrete = constants.%S] {
 // CHECK:STDOUT:     %Cpp.ref.loc8: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %S.ref.loc8: type = name_ref S, imports.%S.decl [concrete = constants.%S]
@@ -459,14 +468,14 @@ fn F() {
 // CHECK:STDOUT:     %t.var_patt: %pattern_type.e6b = var_pattern %t.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %t.var: ref %T.e15 = var %t.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc30: %DefaultOrUnformed.type = facet_value constants.%T.e15, (constants.%DefaultOrUnformed.impl_witness.a11) [concrete = constants.%DefaultOrUnformed.facet.5fe]
-// CHECK:STDOUT:   %.loc30_15.1: %DefaultOrUnformed.type = converted constants.%T.e15, %DefaultOrUnformed.facet.loc30 [concrete = constants.%DefaultOrUnformed.facet.5fe]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc30: %DefaultOrUnformed.type = facet_value constants.%T.e15, (constants.%DefaultOrUnformed.impl_witness.1bd) [concrete = constants.%DefaultOrUnformed.facet.ac4]
+// CHECK:STDOUT:   %.loc30_15.1: %DefaultOrUnformed.type = converted constants.%T.e15, %DefaultOrUnformed.facet.loc30 [concrete = constants.%DefaultOrUnformed.facet.ac4]
 // CHECK:STDOUT:   %as_type.loc30: type = facet_access_type %.loc30_15.1 [concrete = constants.%T.e15]
 // CHECK:STDOUT:   %.loc30_15.2: type = converted %.loc30_15.1, %as_type.loc30 [concrete = constants.%T.e15]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc30_3: ref %T.e15 = splice_block %t.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc30: init %T.e15 to %.loc30_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.2()
-// CHECK:STDOUT:   assign %t.var, %T.as.DefaultOrUnformed.impl.Op.call.loc30
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc30: init %T.e15 to %.loc30_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.2()
+// CHECK:STDOUT:   assign %t.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc30
 // CHECK:STDOUT:   %.loc30_13: type = splice_block %T.ref [concrete = constants.%T.e15] {
 // CHECK:STDOUT:     %Cpp.ref.loc30: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %T.ref: type = name_ref T, imports.%T.decl [concrete = constants.%T.e15]
@@ -480,14 +489,14 @@ fn F() {
 // CHECK:STDOUT:     %u.var_patt: %pattern_type.7da = var_pattern %u.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %u.var: ref %S = var %u.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc41: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.6b7) [concrete = constants.%DefaultOrUnformed.facet.d8f]
-// CHECK:STDOUT:   %.loc41_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc41 [concrete = constants.%DefaultOrUnformed.facet.d8f]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc41: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.a91) [concrete = constants.%DefaultOrUnformed.facet.b0b]
+// CHECK:STDOUT:   %.loc41_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc41 [concrete = constants.%DefaultOrUnformed.facet.b0b]
 // CHECK:STDOUT:   %as_type.loc41: type = facet_access_type %.loc41_15.1 [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc41_15.2: type = converted %.loc41_15.1, %as_type.loc41 [concrete = constants.%S]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc41_3: ref %S = splice_block %u.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc41: init %S to %.loc41_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.3()
-// CHECK:STDOUT:   assign %u.var, %T.as.DefaultOrUnformed.impl.Op.call.loc41
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc41: init %S to %.loc41_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.3()
+// CHECK:STDOUT:   assign %u.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc41
 // CHECK:STDOUT:   %.loc41_13: type = splice_block %S.ref.loc41 [concrete = constants.%S] {
 // CHECK:STDOUT:     %Cpp.ref.loc41: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %S.ref.loc41: type = name_ref S, imports.%S.decl [concrete = constants.%S]
@@ -570,17 +579,26 @@ fn F() {
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %pattern_type.7da: type = pattern_type %S [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6b7: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%S) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.d8f: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.6b7) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %S.Op.type: type = fn_type @S.Op [concrete]
+// CHECK:STDOUT:   %S.Op: %S.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.4cd: <witness> = custom_witness (%S.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.889: %Default.type = facet_value %S, (%custom_witness.4cd) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a91: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.889) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.b0b: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.a91) [concrete]
 // CHECK:STDOUT:   %TakesRValue.cpp_overload_set.type: type = cpp_overload_set_type @TakesRValue.cpp_overload_set [concrete]
 // CHECK:STDOUT:   %TakesRValue.cpp_overload_set.value: %TakesRValue.cpp_overload_set.type = cpp_overload_set_value @TakesRValue.cpp_overload_set [concrete]
 // CHECK:STDOUT:   %T.e15: type = class_type @T [concrete]
 // CHECK:STDOUT:   %pattern_type.e6b: type = pattern_type %T.e15 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a11: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%T.e15) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.5fe: %DefaultOrUnformed.type = facet_value %T.e15, (%DefaultOrUnformed.impl_witness.a11) [concrete]
+// CHECK:STDOUT:   %T.Op.type: type = fn_type @T.Op [concrete]
+// CHECK:STDOUT:   %T.Op: %T.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.3b9: <witness> = custom_witness (%T.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.2fe: %Default.type = facet_value %T.e15, (%custom_witness.3b9) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.1bd: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.2fe) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.ac4: %DefaultOrUnformed.type = facet_value %T.e15, (%DefaultOrUnformed.impl_witness.1bd) [concrete]
 // CHECK:STDOUT:   %empty_struct.a40: %empty_struct_type = struct_value () [concrete]
 // CHECK:STDOUT:   %S.val: %S = struct_value () [concrete]
 // CHECK:STDOUT:   %const: type = const_type %S [concrete]
@@ -599,8 +617,8 @@ fn F() {
 // CHECK:STDOUT:     import Cpp//...
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %S.decl: type = class_decl @S [concrete = constants.%S] {} {}
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %TakesRValue.cpp_overload_set.value: %TakesRValue.cpp_overload_set.type = cpp_overload_set_value @TakesRValue.cpp_overload_set [concrete = constants.%TakesRValue.cpp_overload_set.value]
 // CHECK:STDOUT:   %T.decl: type = class_decl @T [concrete = constants.%T.e15] {} {}
 // CHECK:STDOUT: }
@@ -612,14 +630,14 @@ fn F() {
 // CHECK:STDOUT:     %s.var_patt: %pattern_type.7da = var_pattern %s.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.6b7) [concrete = constants.%DefaultOrUnformed.facet.d8f]
-// CHECK:STDOUT:   %.loc8_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.d8f]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.a91) [concrete = constants.%DefaultOrUnformed.facet.b0b]
+// CHECK:STDOUT:   %.loc8_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.b0b]
 // CHECK:STDOUT:   %as_type.loc8: type = facet_access_type %.loc8_15.1 [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_15.2: type = converted %.loc8_15.1, %as_type.loc8 [concrete = constants.%S]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc8_3: ref %S = splice_block %s.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc8: init %S to %.loc8_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.1()
-// CHECK:STDOUT:   assign %s.var, %T.as.DefaultOrUnformed.impl.Op.call.loc8
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8: init %S to %.loc8_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.1()
+// CHECK:STDOUT:   assign %s.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref.loc8 [concrete = constants.%S] {
 // CHECK:STDOUT:     %Cpp.ref.loc8: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %S.ref.loc8: type = name_ref S, imports.%S.decl [concrete = constants.%S]
@@ -633,14 +651,14 @@ fn F() {
 // CHECK:STDOUT:     %t.var_patt: %pattern_type.e6b = var_pattern %t.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %t.var: ref %T.e15 = var %t.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc19: %DefaultOrUnformed.type = facet_value constants.%T.e15, (constants.%DefaultOrUnformed.impl_witness.a11) [concrete = constants.%DefaultOrUnformed.facet.5fe]
-// CHECK:STDOUT:   %.loc19_15.1: %DefaultOrUnformed.type = converted constants.%T.e15, %DefaultOrUnformed.facet.loc19 [concrete = constants.%DefaultOrUnformed.facet.5fe]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc19: %DefaultOrUnformed.type = facet_value constants.%T.e15, (constants.%DefaultOrUnformed.impl_witness.1bd) [concrete = constants.%DefaultOrUnformed.facet.ac4]
+// CHECK:STDOUT:   %.loc19_15.1: %DefaultOrUnformed.type = converted constants.%T.e15, %DefaultOrUnformed.facet.loc19 [concrete = constants.%DefaultOrUnformed.facet.ac4]
 // CHECK:STDOUT:   %as_type.loc19: type = facet_access_type %.loc19_15.1 [concrete = constants.%T.e15]
 // CHECK:STDOUT:   %.loc19_15.2: type = converted %.loc19_15.1, %as_type.loc19 [concrete = constants.%T.e15]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc19_3: ref %T.e15 = splice_block %t.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc19: init %T.e15 to %.loc19_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.2()
-// CHECK:STDOUT:   assign %t.var, %T.as.DefaultOrUnformed.impl.Op.call.loc19
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc19: init %T.e15 to %.loc19_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.2()
+// CHECK:STDOUT:   assign %t.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc19
 // CHECK:STDOUT:   %.loc19_13: type = splice_block %T.ref [concrete = constants.%T.e15] {
 // CHECK:STDOUT:     %Cpp.ref.loc19: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %T.ref: type = name_ref T, imports.%T.decl [concrete = constants.%T.e15]

toolchain/check/testdata/interop/cpp/function/struct.carbon

@@ -652,11 +652,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk.type: type = fn_type @foo__carbon_thunk [concrete]
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.590: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%S) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.590) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %S.Op.type: type = fn_type @S.Op [concrete]
+// CHECK:STDOUT:   %S.Op: %S.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.4c9: <witness> = custom_witness (%S.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.dcf: %Default.type = facet_value %S, (%custom_witness.4c9) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.33e: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.dcf) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.33e) [concrete]
 // CHECK:STDOUT:   %S.cpp_destructor.type: type = fn_type @S.cpp_destructor [concrete]
 // CHECK:STDOUT:   %S.cpp_destructor: %S.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -678,8 +683,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%s.param: %S) {
@@ -695,14 +700,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.cd8 = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %S = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.590) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.33e) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc10_24.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc10_24.1 [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc10_24.2: type = converted %.loc10_24.1, %as_type [concrete = constants.%S]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc10_3: ref %S = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %S to %.loc10_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %S to %.loc10_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc10_22: type = splice_block %S.ref.loc10 [concrete = constants.%S] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc10: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -774,11 +779,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.cff: type = pattern_type %O [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.938: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%O) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.938) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %O.Op.type: type = fn_type @O.Op [concrete]
+// CHECK:STDOUT:   %O.Op: %O.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.8f6: <witness> = custom_witness (%O.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.d7b: %Default.type = facet_value %O, (%custom_witness.8f6) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.e05: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.d7b) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.e05) [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor.type: type = fn_type @O.cpp_destructor [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor: %O.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -796,8 +806,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%s.param: %S) {
@@ -813,14 +823,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.cff = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %O = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.938) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.e05) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc9_22.1: %DefaultOrUnformed.type = converted constants.%O, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc9_22.1 [concrete = constants.%O]
 // CHECK:STDOUT:   %.loc9_22.2: type = converted %.loc9_22.1, %as_type [concrete = constants.%O]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc9_3: ref %O = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc9_20: type = splice_block %O.ref.loc9 [concrete = constants.%O] {
 // CHECK:STDOUT:     %Cpp.ref.loc9: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %O.ref.loc9: type = name_ref O, imports.%O.decl [concrete = constants.%O]

toolchain/check/testdata/interop/cpp/function/union.carbon

@@ -577,11 +577,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk.type: type = fn_type @foo__carbon_thunk [concrete]
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.860: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%U) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %U, (%DefaultOrUnformed.impl_witness.860) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %U.Op.type: type = fn_type @U.Op [concrete]
+// CHECK:STDOUT:   %U.Op: %U.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.cb9: <witness> = custom_witness (%U.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.916: %Default.type = facet_value %U, (%custom_witness.cb9) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.225: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.916) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %U, (%DefaultOrUnformed.impl_witness.225) [concrete]
 // CHECK:STDOUT:   %U.cpp_destructor.type: type = fn_type @U.cpp_destructor [concrete]
 // CHECK:STDOUT:   %U.cpp_destructor: %U.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -603,8 +608,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%u.param: %U) {
@@ -620,14 +625,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.eb9 = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %U = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%U, (constants.%DefaultOrUnformed.impl_witness.860) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%U, (constants.%DefaultOrUnformed.impl_witness.225) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc10_24.1: %DefaultOrUnformed.type = converted constants.%U, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc10_24.1 [concrete = constants.%U]
 // CHECK:STDOUT:   %.loc10_24.2: type = converted %.loc10_24.1, %as_type [concrete = constants.%U]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc10_3: ref %U = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %U to %.loc10_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %U to %.loc10_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc10_22: type = splice_block %U.ref.loc10 [concrete = constants.%U] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc10: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -699,11 +704,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.cff: type = pattern_type %O [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.938: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%O) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.938) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %O.Op.type: type = fn_type @O.Op [concrete]
+// CHECK:STDOUT:   %O.Op: %O.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.8f6: <witness> = custom_witness (%O.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.d7b: %Default.type = facet_value %O, (%custom_witness.8f6) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.e05: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.d7b) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.e05) [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor.type: type = fn_type @O.cpp_destructor [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor: %O.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -721,8 +731,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%u.param: %U) {
@@ -738,14 +748,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.cff = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %O = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.938) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.e05) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc9_22.1: %DefaultOrUnformed.type = converted constants.%O, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc9_22.1 [concrete = constants.%O]
 // CHECK:STDOUT:   %.loc9_22.2: type = converted %.loc9_22.1, %as_type [concrete = constants.%O]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc9_3: ref %O = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc9_20: type = splice_block %O.ref.loc9 [concrete = constants.%O] {
 // CHECK:STDOUT:     %Cpp.ref.loc9: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %O.ref.loc9: type = name_ref O, imports.%O.decl [concrete = constants.%O]

toolchain/check/testdata/interop/cpp/template/argument_count.carbon

@@ -124,16 +124,21 @@ var too_many: Cpp.FixedSizePack(Cpp.A, Cpp.A).Inner(Cpp.B, Cpp.B, Cpp.B);
 // CHECK:STDOUT:   %TwoTypes: type = class_type @TwoTypes [concrete]
 // CHECK:STDOUT:   %pattern_type.2da: type = pattern_type %TwoTypes [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.679: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TwoTypes) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.679) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TwoTypes.Op.type: type = fn_type @TwoTypes.Op [concrete]
+// CHECK:STDOUT:   %TwoTypes.Op: %TwoTypes.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.2e3: <witness> = custom_witness (%TwoTypes.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.c59: %Default.type = facet_value %TwoTypes, (%custom_witness.2e3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fcc: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.c59) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.fcc) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -147,14 +152,14 @@ var too_many: Cpp.FixedSizePack(Cpp.A, Cpp.A).Inner(Cpp.B, Cpp.B, Cpp.B);
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.679) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.fcc) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc7_34.1: %DefaultOrUnformed.type = converted constants.%TwoTypes, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc7_34.1 [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   %.loc7_34.2: type = converted %.loc7_34.1, %as_type [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TwoTypes = splice_block file.%x.var [concrete = file.%x.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign file.%x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign file.%x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -164,28 +169,45 @@ var too_many: Cpp.FixedSizePack(Cpp.A, Cpp.A).Inner(Cpp.B, Cpp.B, Cpp.B);
 // CHECK:STDOUT:   %TypePack.49edc4.1: type = class_type @TypePack.1 [concrete]
 // CHECK:STDOUT:   %pattern_type.9db866.1: type = pattern_type %TypePack.49edc4.1 [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.bca864.1: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TypePack.49edc4.1) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.95dbcc.1: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.1, (%DefaultOrUnformed.impl_witness.bca864.1) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TypePack.Op.type.c6ed4b.1: type = fn_type @TypePack.Op.1 [concrete]
+// CHECK:STDOUT:   %TypePack.Op.4bf03f.1: %TypePack.Op.type.c6ed4b.1 = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.969c90.1: <witness> = custom_witness (%TypePack.Op.4bf03f.1), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.314ffa.1: %Default.type = facet_value %TypePack.49edc4.1, (%custom_witness.969c90.1) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fd05a0.1: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.314ffa.1) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.7756c0.1: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.1, (%DefaultOrUnformed.impl_witness.fd05a0.1) [concrete]
 // CHECK:STDOUT:   %TypePack.49edc4.2: type = class_type @TypePack.2 [concrete]
 // CHECK:STDOUT:   %pattern_type.9db866.2: type = pattern_type %TypePack.49edc4.2 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.bca864.2: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TypePack.49edc4.2) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.95dbcc.2: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.2, (%DefaultOrUnformed.impl_witness.bca864.2) [concrete]
+// CHECK:STDOUT:   %TypePack.Op.type.c6ed4b.2: type = fn_type @TypePack.Op.2 [concrete]
+// CHECK:STDOUT:   %TypePack.Op.4bf03f.2: %TypePack.Op.type.c6ed4b.2 = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.969c90.2: <witness> = custom_witness (%TypePack.Op.4bf03f.2), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.314ffa.2: %Default.type = facet_value %TypePack.49edc4.2, (%custom_witness.969c90.2) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fd05a0.2: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.314ffa.2) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.7756c0.2: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.2, (%DefaultOrUnformed.impl_witness.fd05a0.2) [concrete]
 // CHECK:STDOUT:   %TypePack.49edc4.3: type = class_type @TypePack.3 [concrete]
 // CHECK:STDOUT:   %pattern_type.9db866.3: type = pattern_type %TypePack.49edc4.3 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.bca864.3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TypePack.49edc4.3) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.95dbcc.3: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.3, (%DefaultOrUnformed.impl_witness.bca864.3) [concrete]
+// CHECK:STDOUT:   %TypePack.Op.type.c6ed4b.3: type = fn_type @TypePack.Op.3 [concrete]
+// CHECK:STDOUT:   %TypePack.Op.4bf03f.3: %TypePack.Op.type.c6ed4b.3 = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.969c90.3: <witness> = custom_witness (%TypePack.Op.4bf03f.3), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.314ffa.3: %Default.type = facet_value %TypePack.49edc4.3, (%custom_witness.969c90.3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fd05a0.3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.314ffa.3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.7756c0.3: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.3, (%DefaultOrUnformed.impl_witness.fd05a0.3) [concrete]
 // CHECK:STDOUT:   %TypePack.49edc4.4: type = class_type @TypePack.4 [concrete]
 // CHECK:STDOUT:   %pattern_type.9db866.4: type = pattern_type %TypePack.49edc4.4 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.bca864.4: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TypePack.49edc4.4) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.95dbcc.4: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.4, (%DefaultOrUnformed.impl_witness.bca864.4) [concrete]
+// CHECK:STDOUT:   %TypePack.Op.type.c6ed4b.4: type = fn_type @TypePack.Op.4 [concrete]
+// CHECK:STDOUT:   %TypePack.Op.4bf03f.4: %TypePack.Op.type.c6ed4b.4 = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.969c90.4: <witness> = custom_witness (%TypePack.Op.4bf03f.4), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.314ffa.4: %Default.type = facet_value %TypePack.49edc4.4, (%custom_witness.969c90.4) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fd05a0.4: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.314ffa.4) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.7756c0.4: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.4, (%DefaultOrUnformed.impl_witness.fd05a0.4) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -217,38 +239,38 @@ var too_many: Cpp.FixedSizePack(Cpp.A, Cpp.A).Inner(Cpp.B, Cpp.B, Cpp.B);
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc7: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.1, (constants.%DefaultOrUnformed.impl_witness.bca864.1) [concrete = constants.%DefaultOrUnformed.facet.95dbcc.1]
-// CHECK:STDOUT:   %.loc7_23.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.1, %DefaultOrUnformed.facet.loc7 [concrete = constants.%DefaultOrUnformed.facet.95dbcc.1]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc7: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.1, (constants.%DefaultOrUnformed.impl_witness.fd05a0.1) [concrete = constants.%DefaultOrUnformed.facet.7756c0.1]
+// CHECK:STDOUT:   %.loc7_23.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.1, %DefaultOrUnformed.facet.loc7 [concrete = constants.%DefaultOrUnformed.facet.7756c0.1]
 // CHECK:STDOUT:   %as_type.loc7: type = facet_access_type %.loc7_23.1 [concrete = constants.%TypePack.49edc4.1]
 // CHECK:STDOUT:   %.loc7_23.2: type = converted %.loc7_23.1, %as_type.loc7 [concrete = constants.%TypePack.49edc4.1]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TypePack.49edc4.1 = splice_block file.%a0.var [concrete = file.%a0.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc7: init %TypePack.49edc4.1 to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.1()
-// CHECK:STDOUT:   assign file.%a0.var, %T.as.DefaultOrUnformed.impl.Op.call.loc7
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.2, (constants.%DefaultOrUnformed.impl_witness.bca864.2) [concrete = constants.%DefaultOrUnformed.facet.95dbcc.2]
-// CHECK:STDOUT:   %.loc8_28.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.2, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.95dbcc.2]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc7: init %TypePack.49edc4.1 to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.1()
+// CHECK:STDOUT:   assign file.%a0.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc7
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.2, (constants.%DefaultOrUnformed.impl_witness.fd05a0.2) [concrete = constants.%DefaultOrUnformed.facet.7756c0.2]
+// CHECK:STDOUT:   %.loc8_28.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.2, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.7756c0.2]
 // CHECK:STDOUT:   %as_type.loc8: type = facet_access_type %.loc8_28.1 [concrete = constants.%TypePack.49edc4.2]
 // CHECK:STDOUT:   %.loc8_28.2: type = converted %.loc8_28.1, %as_type.loc8 [concrete = constants.%TypePack.49edc4.2]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc8_1: ref %TypePack.49edc4.2 = splice_block file.%a1.var [concrete = file.%a1.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc8: init %TypePack.49edc4.2 to %.loc8_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.2()
-// CHECK:STDOUT:   assign file.%a1.var, %T.as.DefaultOrUnformed.impl.Op.call.loc8
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc9: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.3, (constants.%DefaultOrUnformed.impl_witness.bca864.3) [concrete = constants.%DefaultOrUnformed.facet.95dbcc.3]
-// CHECK:STDOUT:   %.loc9_35.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.3, %DefaultOrUnformed.facet.loc9 [concrete = constants.%DefaultOrUnformed.facet.95dbcc.3]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8: init %TypePack.49edc4.2 to %.loc8_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.2()
+// CHECK:STDOUT:   assign file.%a1.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc9: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.3, (constants.%DefaultOrUnformed.impl_witness.fd05a0.3) [concrete = constants.%DefaultOrUnformed.facet.7756c0.3]
+// CHECK:STDOUT:   %.loc9_35.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.3, %DefaultOrUnformed.facet.loc9 [concrete = constants.%DefaultOrUnformed.facet.7756c0.3]
 // CHECK:STDOUT:   %as_type.loc9: type = facet_access_type %.loc9_35.1 [concrete = constants.%TypePack.49edc4.3]
 // CHECK:STDOUT:   %.loc9_35.2: type = converted %.loc9_35.1, %as_type.loc9 [concrete = constants.%TypePack.49edc4.3]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc9_1: ref %TypePack.49edc4.3 = splice_block file.%a2.var [concrete = file.%a2.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc9: init %TypePack.49edc4.3 to %.loc9_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.3()
-// CHECK:STDOUT:   assign file.%a2.var, %T.as.DefaultOrUnformed.impl.Op.call.loc9
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc10: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.4, (constants.%DefaultOrUnformed.impl_witness.bca864.4) [concrete = constants.%DefaultOrUnformed.facet.95dbcc.4]
-// CHECK:STDOUT:   %.loc10_42.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.4, %DefaultOrUnformed.facet.loc10 [concrete = constants.%DefaultOrUnformed.facet.95dbcc.4]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc9: init %TypePack.49edc4.3 to %.loc9_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.3()
+// CHECK:STDOUT:   assign file.%a2.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc9
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc10: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.4, (constants.%DefaultOrUnformed.impl_witness.fd05a0.4) [concrete = constants.%DefaultOrUnformed.facet.7756c0.4]
+// CHECK:STDOUT:   %.loc10_42.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.4, %DefaultOrUnformed.facet.loc10 [concrete = constants.%DefaultOrUnformed.facet.7756c0.4]
 // CHECK:STDOUT:   %as_type.loc10: type = facet_access_type %.loc10_42.1 [concrete = constants.%TypePack.49edc4.4]
 // CHECK:STDOUT:   %.loc10_42.2: type = converted %.loc10_42.1, %as_type.loc10 [concrete = constants.%TypePack.49edc4.4]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc10_1: ref %TypePack.49edc4.4 = splice_block file.%a3.var [concrete = file.%a3.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc10: init %TypePack.49edc4.4 to %.loc10_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.4()
-// CHECK:STDOUT:   assign file.%a3.var, %T.as.DefaultOrUnformed.impl.Op.call.loc10
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc10: init %TypePack.49edc4.4 to %.loc10_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.4()
+// CHECK:STDOUT:   assign file.%a3.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc10
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/interop/cpp/template/template_template_param.carbon

@@ -86,16 +86,21 @@ var x: Cpp.TwoTemplates(Cpp.A, true);
 // CHECK:STDOUT:   %TwoTemplates: type = class_type @TwoTemplates [concrete]
 // CHECK:STDOUT:   %pattern_type.2b7: type = pattern_type %TwoTemplates [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.cea: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TwoTemplates) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTemplates, (%DefaultOrUnformed.impl_witness.cea) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TwoTemplates.Op.type: type = fn_type @TwoTemplates.Op [concrete]
+// CHECK:STDOUT:   %TwoTemplates.Op: %TwoTemplates.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.6e5: <witness> = custom_witness (%TwoTemplates.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.90a: %Default.type = facet_value %TwoTemplates, (%custom_witness.6e5) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.18b: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.90a) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTemplates, (%DefaultOrUnformed.impl_witness.18b) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -109,14 +114,14 @@ var x: Cpp.TwoTemplates(Cpp.A, true);
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTemplates, (constants.%DefaultOrUnformed.impl_witness.cea) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTemplates, (constants.%DefaultOrUnformed.impl_witness.18b) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc7_38.1: %DefaultOrUnformed.type = converted constants.%TwoTemplates, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc7_38.1 [concrete = constants.%TwoTemplates]
 // CHECK:STDOUT:   %.loc7_38.2: type = converted %.loc7_38.1, %as_type [concrete = constants.%TwoTemplates]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TwoTemplates = splice_block file.%x.var [concrete = file.%x.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %TwoTemplates to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign file.%x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %TwoTemplates to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign file.%x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/interop/cpp/template/type_param.carbon

@@ -70,16 +70,21 @@ var x: Cpp.TwoTypes(Cpp.A, {});
 // CHECK:STDOUT:   %TwoTypes: type = class_type @TwoTypes [concrete]
 // CHECK:STDOUT:   %pattern_type.2da: type = pattern_type %TwoTypes [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.679: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TwoTypes) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.679) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TwoTypes.Op.type: type = fn_type @TwoTypes.Op [concrete]
+// CHECK:STDOUT:   %TwoTypes.Op: %TwoTypes.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.2e3: <witness> = custom_witness (%TwoTypes.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.c59: %Default.type = facet_value %TwoTypes, (%custom_witness.2e3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fcc: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.c59) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.fcc) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -93,14 +98,14 @@ var x: Cpp.TwoTypes(Cpp.A, {});
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.679) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.fcc) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc7_34.1: %DefaultOrUnformed.type = converted constants.%TwoTypes, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc7_34.1 [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   %.loc7_34.2: type = converted %.loc7_34.1, %as_type [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TwoTypes = splice_block file.%x.var [concrete = file.%x.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign file.%x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign file.%x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -110,16 +115,21 @@ var x: Cpp.TwoTypes(Cpp.A, {});
 // CHECK:STDOUT:   %TwoTypes: type = class_type @TwoTypes [concrete]
 // CHECK:STDOUT:   %pattern_type.2da: type = pattern_type %TwoTypes [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.679: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TwoTypes) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.679) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TwoTypes.Op.type: type = fn_type @TwoTypes.Op [concrete]
+// CHECK:STDOUT:   %TwoTypes.Op: %TwoTypes.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.2e3: <witness> = custom_witness (%TwoTypes.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.c59: %Default.type = facet_value %TwoTypes, (%custom_witness.2e3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fcc: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.c59) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.fcc) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -133,14 +143,14 @@ var x: Cpp.TwoTypes(Cpp.A, {});
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.679) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.fcc) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc7_32.1: %DefaultOrUnformed.type = converted constants.%TwoTypes, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc7_32.1 [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   %.loc7_32.2: type = converted %.loc7_32.1, %as_type [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TwoTypes = splice_block file.%x.var [concrete = file.%x.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign file.%x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign file.%x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/namespace/merging_with_indirections.carbon

@@ -171,10 +171,10 @@ fn Run() {
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
 // CHECK:STDOUT:   %pattern_type.272: type = pattern_type %A [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.c9e: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%A) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.c9e: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%A) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.ffd: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%A) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.993: %T.as.DefaultOrUnformed.impl.Op.type.ffd = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %A, (%DefaultOrUnformed.impl_witness.c9e) [concrete]
@@ -209,7 +209,7 @@ fn Run() {
 // CHECK:STDOUT:   %Other.A: type = import_ref Other//a, A, loaded [concrete = constants.%A]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/operators/builtin/fail_assignment_to_non_assignable.carbon

@@ -136,7 +136,7 @@ fn Main() {
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8d3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%i32) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8d3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%i32) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.c67: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%i32) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.137: %T.as.DefaultOrUnformed.impl.Op.type.c67 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %i32, (%DefaultOrUnformed.impl_witness.8d3) [concrete]
@@ -171,7 +171,7 @@ fn Main() {
 // CHECK:STDOUT:   %Copy.impl_witness_table.b1c = impl_witness_table (%Core.import_ref.1a7), @type.as.Copy.impl [concrete]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %Core.Destroy: type = import_ref Core//prelude/parts/destroy, Destroy, loaded [concrete = constants.%Destroy.type]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/packages/fail_conflict_no_namespaces.carbon

@@ -74,10 +74,10 @@ import library "var";
 // CHECK:STDOUT:   %i32: type = class_type @Int, @Int(%int_32) [concrete]
 // CHECK:STDOUT:   %pattern_type.7ce: type = pattern_type %i32 [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8d3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%i32) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8d3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%i32) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.c67: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%i32) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.137: %T.as.DefaultOrUnformed.impl.Op.type.c67 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %i32, (%DefaultOrUnformed.impl_witness.8d3) [concrete]
@@ -94,7 +94,7 @@ import library "var";
 // CHECK:STDOUT:   %Core.Int: %Int.type = import_ref Core//prelude/parts/int, Int, loaded [concrete = constants.%Int.generic]
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/primitives/type_literals.carbon

@@ -296,31 +296,31 @@ var test_str: str = ();
 // CHECK:STDOUT:   %i8: type = class_type @Int, @Int(%int_8) [concrete]
 // CHECK:STDOUT:   %pattern_type.e3f: type = pattern_type %i8 [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8de: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%i8) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8de: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%i8) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.e22: %DefaultOrUnformed.type = facet_value %i8, (%DefaultOrUnformed.impl_witness.8de) [concrete]
 // CHECK:STDOUT:   %int_16: Core.IntLiteral = int_value 16 [concrete]
 // CHECK:STDOUT:   %i16: type = class_type @Int, @Int(%int_16) [concrete]
 // CHECK:STDOUT:   %pattern_type.2f8: type = pattern_type %i16 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.e93: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%i16) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.e93: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%i16) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.cc9: %DefaultOrUnformed.type = facet_value %i16, (%DefaultOrUnformed.impl_witness.e93) [concrete]
 // CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [concrete]
 // CHECK:STDOUT:   %i32: type = class_type @Int, @Int(%int_32) [concrete]
 // CHECK:STDOUT:   %pattern_type.7ce: type = pattern_type %i32 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8d3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%i32) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8d3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%i32) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.266: %DefaultOrUnformed.type = facet_value %i32, (%DefaultOrUnformed.impl_witness.8d3) [concrete]
 // CHECK:STDOUT:   %int_64: Core.IntLiteral = int_value 64 [concrete]
 // CHECK:STDOUT:   %i64: type = class_type @Int, @Int(%int_64) [concrete]
 // CHECK:STDOUT:   %pattern_type.95b: type = pattern_type %i64 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.3a1: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%i64) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.3a1: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%i64) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.161: %DefaultOrUnformed.type = facet_value %i64, (%DefaultOrUnformed.impl_witness.3a1) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -394,31 +394,31 @@ var test_str: str = ();
 // CHECK:STDOUT:   %u8: type = class_type @UInt, @UInt(%int_8) [concrete]
 // CHECK:STDOUT:   %pattern_type.8f3: type = pattern_type %u8 [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.341: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%u8) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.341: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%u8) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.56df: %DefaultOrUnformed.type = facet_value %u8, (%DefaultOrUnformed.impl_witness.341) [concrete]
 // CHECK:STDOUT:   %int_16: Core.IntLiteral = int_value 16 [concrete]
 // CHECK:STDOUT:   %u16: type = class_type @UInt, @UInt(%int_16) [concrete]
 // CHECK:STDOUT:   %pattern_type.9db: type = pattern_type %u16 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.f79: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%u16) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.f79: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%u16) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.ad7: %DefaultOrUnformed.type = facet_value %u16, (%DefaultOrUnformed.impl_witness.f79) [concrete]
 // CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [concrete]
 // CHECK:STDOUT:   %u32: type = class_type @UInt, @UInt(%int_32) [concrete]
 // CHECK:STDOUT:   %pattern_type.4a9: type = pattern_type %u32 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.486: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%u32) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.486: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%u32) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.5f8: %DefaultOrUnformed.type = facet_value %u32, (%DefaultOrUnformed.impl_witness.486) [concrete]
 // CHECK:STDOUT:   %int_64: Core.IntLiteral = int_value 64 [concrete]
 // CHECK:STDOUT:   %u64: type = class_type @UInt, @UInt(%int_64) [concrete]
 // CHECK:STDOUT:   %pattern_type.157: type = pattern_type %u64 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8ea: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%u64) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.8ea: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%u64) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.56d3: %DefaultOrUnformed.type = facet_value %u64, (%DefaultOrUnformed.impl_witness.8ea) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -492,31 +492,31 @@ var test_str: str = ();
 // CHECK:STDOUT:   %f16.a6a: type = class_type @Float, @Float(%int_16) [concrete]
 // CHECK:STDOUT:   %pattern_type.cd1: type = pattern_type %f16.a6a [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a55: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%f16.a6a) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a55: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%f16.a6a) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.671: %DefaultOrUnformed.type = facet_value %f16.a6a, (%DefaultOrUnformed.impl_witness.a55) [concrete]
 // CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [concrete]
 // CHECK:STDOUT:   %f32.97e: type = class_type @Float, @Float(%int_32) [concrete]
 // CHECK:STDOUT:   %pattern_type.201: type = pattern_type %f32.97e [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.567: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%f32.97e) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.567: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%f32.97e) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.60c: %DefaultOrUnformed.type = facet_value %f32.97e, (%DefaultOrUnformed.impl_witness.567) [concrete]
 // CHECK:STDOUT:   %int_64: Core.IntLiteral = int_value 64 [concrete]
 // CHECK:STDOUT:   %f64.d77: type = class_type @Float, @Float(%int_64) [concrete]
 // CHECK:STDOUT:   %pattern_type.0ae: type = pattern_type %f64.d77 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.461: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%f64.d77) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.461: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%f64.d77) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.625: %DefaultOrUnformed.type = facet_value %f64.d77, (%DefaultOrUnformed.impl_witness.461) [concrete]
 // CHECK:STDOUT:   %int_128: Core.IntLiteral = int_value 128 [concrete]
 // CHECK:STDOUT:   %f128.b8c: type = class_type @Float, @Float(%int_128) [concrete]
 // CHECK:STDOUT:   %pattern_type.22c: type = pattern_type %f128.b8c [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.39e: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%f128.b8c) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.39e: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%f128.b8c) [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet.560: %DefaultOrUnformed.type = facet_value %f128.b8c, (%DefaultOrUnformed.impl_witness.39e) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/check/testdata/var/export_name.carbon

@@ -49,10 +49,10 @@ var w: () = v;
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.cb1: type = pattern_type %empty_tuple.type [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
+// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.159: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%empty_tuple.type) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.159: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.349, @T.as.DefaultOrUnformed.impl(%empty_tuple.type) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.f72: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%empty_tuple.type) [concrete]
 // CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.365: %T.as.DefaultOrUnformed.impl.Op.type.f72 = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %empty_tuple.type, (%DefaultOrUnformed.impl_witness.159) [concrete]
@@ -67,7 +67,7 @@ var w: () = v;
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.DefaultOrUnformed: type = import_ref Core//prelude/parts/default, DefaultOrUnformed, loaded [concrete = constants.%DefaultOrUnformed.type]
 // CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.349 = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {

toolchain/lower/testdata/interop/cpp/constructor.carbon

@@ -39,6 +39,43 @@ fn G() {
   let _: Cpp.C = ();
 }
 
+// --- implicit_default.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp library "default.h";
+
+fn F() {
+  var _: Cpp.C;
+}
+
+// --- defaulted_default.h
+
+struct ImplicitlyDefaultedDefault {
+  int x_ = 1;
+};
+
+struct ExplicitlyDefaultedDefault {
+  ExplicitlyDefaultedDefault() = default;
+  int x_ = 1;
+};
+
+// --- defaulted_default.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp library "defaulted_default.h";
+
+fn F() {
+  let _: Cpp.ImplicitlyDefaultedDefault =
+      Cpp.ImplicitlyDefaultedDefault.ImplicitlyDefaultedDefault();
+  var _: Cpp.ImplicitlyDefaultedDefault;
+
+  let _: Cpp.ExplicitlyDefaultedDefault =
+      Cpp.ExplicitlyDefaultedDefault.ExplicitlyDefaultedDefault();
+  var _: Cpp.ExplicitlyDefaultedDefault;
+}
+
 // ============================================================================
 // Copy constructor
 // ============================================================================
@@ -231,6 +268,263 @@ fn Four() {
 // CHECK:STDOUT: !22 = distinct !DISubprogram(name: "G", linkageName: "_CG.Main", scope: null, file: !6, line: 10, type: !18, spFlags: DISPFlagDefinition, unit: !5)
 // CHECK:STDOUT: !23 = !DILocation(line: 11, column: 18, scope: !22)
 // CHECK:STDOUT: !24 = !DILocation(line: 10, column: 1, scope: !22)
+// CHECK:STDOUT: ; ModuleID = 'implicit_default.carbon'
+// CHECK:STDOUT: source_filename = "implicit_default.carbon"
+// CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+// CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
+// CHECK:STDOUT:
+// CHECK:STDOUT: %class.C = type { i32, i32 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: $_ZN1CC2Ev = comdat any
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_ZN1CC1Ev.carbon_thunk(ptr noundef %return) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   call void @_ZN1CC2Ev(ptr noundef nonnull align 4 dereferenceable(8) %0)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN1CC2Ev(ptr noundef nonnull align 4 dereferenceable(8) %this) unnamed_addr #1 comdat align 2 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
+// CHECK:STDOUT:   %x_ = getelementptr inbounds nuw %class.C, ptr %this1, i32 0, i32 0
+// CHECK:STDOUT:   store i32 8, ptr %x_, align 4, !tbaa !14
+// CHECK:STDOUT:   %y_ = getelementptr inbounds nuw %class.C, ptr %this1, i32 0, i32 1
+// CHECK:STDOUT:   store i32 9, ptr %y_, align 4, !tbaa !16
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CF.Main() #2 !dbg !17 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %_.var = alloca [8 x i8], align 1, !dbg !20
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var), !dbg !20
+// CHECK:STDOUT:   call void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.93349b0fe912a29b"(ptr %_.var), !dbg !20
+// CHECK:STDOUT:   ret void, !dbg !21
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_COp:thunk.C.Cpp"(ptr sret([8 x i8]) %return) #3 !dbg !22 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_ZN1CC1Ev.carbon_thunk(ptr %return), !dbg !27
+// CHECK:STDOUT:   ret void, !dbg !27
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #4
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.93349b0fe912a29b"(ptr sret([8 x i8]) %return) #2 !dbg !28 {
+// CHECK:STDOUT:   call void @"_COp:thunk.C.Cpp"(ptr %return), !dbg !30
+// CHECK:STDOUT:   ret void, !dbg !31
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #4 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!5}
+// CHECK:STDOUT: !llvm.errno.tbaa = !{!7}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = !{i32 8, !"PIC Level", i32 2}
+// CHECK:STDOUT: !3 = !{i32 7, !"PIE Level", i32 2}
+// CHECK:STDOUT: !4 = !{i32 7, !"uwtable", i32 2}
+// CHECK:STDOUT: !5 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !6, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !6 = !DIFile(filename: "implicit_default.carbon", directory: "")
+// CHECK:STDOUT: !7 = !{!8, !8, i64 0}
+// CHECK:STDOUT: !8 = !{!"int", !9, i64 0}
+// CHECK:STDOUT: !9 = !{!"omnipotent char", !10, i64 0}
+// CHECK:STDOUT: !10 = !{!"Simple C++ TBAA"}
+// CHECK:STDOUT: !11 = !{!12, !12, i64 0}
+// CHECK:STDOUT: !12 = !{!"p1 _ZTS1C", !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"any pointer", !9, i64 0}
+// CHECK:STDOUT: !14 = !{!15, !8, i64 0}
+// CHECK:STDOUT: !15 = !{!"_ZTS1C", !8, i64 0, !8, i64 4}
+// CHECK:STDOUT: !16 = !{!15, !8, i64 4}
+// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "F", linkageName: "_CF.Main", scope: null, file: !6, line: 6, type: !18, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !18 = !DISubroutineType(types: !19)
+// CHECK:STDOUT: !19 = !{null}
+// CHECK:STDOUT: !20 = !DILocation(line: 7, column: 3, scope: !17)
+// CHECK:STDOUT: !21 = !DILocation(line: 6, column: 1, scope: !17)
+// CHECK:STDOUT: !22 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.C.Cpp", scope: null, file: !23, line: 4, type: !24, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !23 = !DIFile(filename: "./default.h", directory: "")
+// CHECK:STDOUT: !24 = !DISubroutineType(types: !25)
+// CHECK:STDOUT: !25 = !{!26}
+// CHECK:STDOUT: !26 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !27 = !DILocation(line: 4, column: 3, scope: !22)
+// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "Op", linkageName: "_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.93349b0fe912a29b", scope: null, file: !29, line: 9, type: !24, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !29 = !DIFile(filename: "min_prelude/parts/default.carbon", directory: "")
+// CHECK:STDOUT: !30 = !DILocation(line: 9, column: 28, scope: !28)
+// CHECK:STDOUT: !31 = !DILocation(line: 9, column: 21, scope: !28)
+// CHECK:STDOUT: ; ModuleID = 'defaulted_default.carbon'
+// CHECK:STDOUT: source_filename = "defaulted_default.carbon"
+// CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+// CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
+// CHECK:STDOUT:
+// CHECK:STDOUT: %struct.ImplicitlyDefaultedDefault = type { i32 }
+// CHECK:STDOUT: %struct.ExplicitlyDefaultedDefault = type { i32 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: $_ZN26ImplicitlyDefaultedDefaultC2Ev = comdat any
+// CHECK:STDOUT:
+// CHECK:STDOUT: $_ZN26ExplicitlyDefaultedDefaultC2Ev = comdat any
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress nounwind uwtable
+// CHECK:STDOUT: define dso_local void @_ZN26ImplicitlyDefaultedDefaultC1Ev.carbon_thunk(ptr noundef %return) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   call void @_ZN26ImplicitlyDefaultedDefaultC2Ev(ptr noundef nonnull align 4 dereferenceable(4) %0) #3
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN26ImplicitlyDefaultedDefaultC2Ev(ptr noundef nonnull align 4 dereferenceable(4) %this) unnamed_addr #1 comdat align 2 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
+// CHECK:STDOUT:   %x_ = getelementptr inbounds nuw %struct.ImplicitlyDefaultedDefault, ptr %this1, i32 0, i32 0
+// CHECK:STDOUT:   store i32 1, ptr %x_, align 4, !tbaa !14
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress nounwind uwtable
+// CHECK:STDOUT: define dso_local void @_ZN26ExplicitlyDefaultedDefaultC1Ev.carbon_thunk(ptr noundef %return) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   call void @_ZN26ExplicitlyDefaultedDefaultC2Ev(ptr noundef nonnull align 4 dereferenceable(4) %0) #3
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN26ExplicitlyDefaultedDefaultC2Ev(ptr noundef nonnull align 4 dereferenceable(4) %this) unnamed_addr #2 comdat align 2 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
+// CHECK:STDOUT:   %x_ = getelementptr inbounds nuw %struct.ExplicitlyDefaultedDefault, ptr %this1, i32 0, i32 0
+// CHECK:STDOUT:   store i32 1, ptr %x_, align 4, !tbaa !18
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CF.Main() #3 !dbg !20 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc8_65.1.temp = alloca [4 x i8], align 1, !dbg !23
+// CHECK:STDOUT:   %_.var.loc9 = alloca [4 x i8], align 1, !dbg !24
+// CHECK:STDOUT:   %.loc12_65.1.temp = alloca [4 x i8], align 1, !dbg !25
+// CHECK:STDOUT:   %_.var.loc13 = alloca [4 x i8], align 1, !dbg !26
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc8_65.1.temp), !dbg !23
+// CHECK:STDOUT:   call void @_ZN26ImplicitlyDefaultedDefaultC1Ev.carbon_thunk(ptr %.loc8_65.1.temp), !dbg !23
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var.loc9), !dbg !24
+// CHECK:STDOUT:   call void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.22b4681b019423d7"(ptr %_.var.loc9), !dbg !24
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc12_65.1.temp), !dbg !25
+// CHECK:STDOUT:   call void @_ZN26ExplicitlyDefaultedDefaultC1Ev.carbon_thunk(ptr %.loc12_65.1.temp), !dbg !25
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var.loc13), !dbg !26
+// CHECK:STDOUT:   call void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.1a27c303748a2360"(ptr %_.var.loc13), !dbg !26
+// CHECK:STDOUT:   ret void, !dbg !27
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_COp:thunk.ImplicitlyDefaultedDefault.Cpp"(ptr sret([4 x i8]) %return) #4 !dbg !28 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_ZN26ImplicitlyDefaultedDefaultC1Ev.carbon_thunk(ptr %return), !dbg !33
+// CHECK:STDOUT:   ret void, !dbg !33
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_COp:thunk.ExplicitlyDefaultedDefault.Cpp"(ptr sret([4 x i8]) %return) #4 !dbg !34 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_ZN26ExplicitlyDefaultedDefaultC1Ev.carbon_thunk(ptr %return), !dbg !35
+// CHECK:STDOUT:   ret void, !dbg !35
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #5
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.22b4681b019423d7"(ptr sret([4 x i8]) %return) #3 !dbg !36 {
+// CHECK:STDOUT:   call void @"_COp:thunk.ImplicitlyDefaultedDefault.Cpp"(ptr %return), !dbg !38
+// CHECK:STDOUT:   ret void, !dbg !39
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.1a27c303748a2360"(ptr sret([4 x i8]) %return) #3 !dbg !40 {
+// CHECK:STDOUT:   call void @"_COp:thunk.ExplicitlyDefaultedDefault.Cpp"(ptr %return), !dbg !41
+// CHECK:STDOUT:   ret void, !dbg !42
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; uselistorder directives
+// CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 3, 2, 1, 0 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #3 = { nounwind }
+// CHECK:STDOUT: attributes #4 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #5 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!5}
+// CHECK:STDOUT: !llvm.errno.tbaa = !{!7}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = !{i32 8, !"PIC Level", i32 2}
+// CHECK:STDOUT: !3 = !{i32 7, !"PIE Level", i32 2}
+// CHECK:STDOUT: !4 = !{i32 7, !"uwtable", i32 2}
+// CHECK:STDOUT: !5 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !6, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !6 = !DIFile(filename: "defaulted_default.carbon", directory: "")
+// CHECK:STDOUT: !7 = !{!8, !8, i64 0}
+// CHECK:STDOUT: !8 = !{!"int", !9, i64 0}
+// CHECK:STDOUT: !9 = !{!"omnipotent char", !10, i64 0}
+// CHECK:STDOUT: !10 = !{!"Simple C++ TBAA"}
+// CHECK:STDOUT: !11 = !{!12, !12, i64 0}
+// CHECK:STDOUT: !12 = !{!"p1 _ZTS26ImplicitlyDefaultedDefault", !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"any pointer", !9, i64 0}
+// CHECK:STDOUT: !14 = !{!15, !8, i64 0}
+// CHECK:STDOUT: !15 = !{!"_ZTS26ImplicitlyDefaultedDefault", !8, i64 0}
+// CHECK:STDOUT: !16 = !{!17, !17, i64 0}
+// CHECK:STDOUT: !17 = !{!"p1 _ZTS26ExplicitlyDefaultedDefault", !13, i64 0}
+// CHECK:STDOUT: !18 = !{!19, !8, i64 0}
+// CHECK:STDOUT: !19 = !{!"_ZTS26ExplicitlyDefaultedDefault", !8, i64 0}
+// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "F", linkageName: "_CF.Main", scope: null, file: !6, line: 6, type: !21, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !21 = !DISubroutineType(types: !22)
+// CHECK:STDOUT: !22 = !{null}
+// CHECK:STDOUT: !23 = !DILocation(line: 8, column: 7, scope: !20)
+// CHECK:STDOUT: !24 = !DILocation(line: 9, column: 3, scope: !20)
+// CHECK:STDOUT: !25 = !DILocation(line: 12, column: 7, scope: !20)
+// CHECK:STDOUT: !26 = !DILocation(line: 13, column: 3, scope: !20)
+// CHECK:STDOUT: !27 = !DILocation(line: 6, column: 1, scope: !20)
+// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.ImplicitlyDefaultedDefault.Cpp", scope: null, file: !29, line: 2, type: !30, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !29 = !DIFile(filename: "./defaulted_default.h", directory: "")
+// CHECK:STDOUT: !30 = !DISubroutineType(types: !31)
+// CHECK:STDOUT: !31 = !{!32}
+// CHECK:STDOUT: !32 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !33 = !DILocation(line: 2, column: 8, scope: !28)
+// CHECK:STDOUT: !34 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.ExplicitlyDefaultedDefault.Cpp", scope: null, file: !29, line: 7, type: !30, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !35 = !DILocation(line: 7, column: 3, scope: !34)
+// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "Op", linkageName: "_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.22b4681b019423d7", scope: null, file: !37, line: 9, type: !30, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !37 = !DIFile(filename: "min_prelude/parts/default.carbon", directory: "")
+// CHECK:STDOUT: !38 = !DILocation(line: 9, column: 28, scope: !36)
+// CHECK:STDOUT: !39 = !DILocation(line: 9, column: 21, scope: !36)
+// CHECK:STDOUT: !40 = distinct !DISubprogram(name: "Op", linkageName: "_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.1a27c303748a2360", scope: null, file: !37, line: 9, type: !30, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !41 = !DILocation(line: 9, column: 28, scope: !40)
+// CHECK:STDOUT: !42 = !DILocation(line: 9, column: 21, scope: !40)
 // CHECK:STDOUT: ; ModuleID = 'call_copy.carbon'
 // CHECK:STDOUT: source_filename = "call_copy.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"

toolchain/lower/testdata/interop/cpp/parameters.carbon

@@ -302,8 +302,17 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: %struct.X = type { i32, i32, i32 }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress nounwind uwtable
+// CHECK:STDOUT: define dso_local void @_ZN1XC1Ev.carbon_thunk(ptr noundef %return) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z11pass_struct1X.carbon_thunk(ptr noundef %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z11pass_struct1X.carbon_thunk(ptr noundef %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %struct.X, align 4
@@ -320,16 +329,17 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z11pass_struct1X(i64, i32) #1
+// CHECK:STDOUT: declare void @_Z11pass_struct1X(i64, i32) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #2
+// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #3
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CTest.Main() #3 !dbg !15 {
+// CHECK:STDOUT: define void @_CTest.Main() #4 !dbg !15 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %x.var = alloca [12 x i8], align 1, !dbg !18
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %x.var), !dbg !18
+// CHECK:STDOUT:   call void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.64f6b96556a8f2d4"(ptr %x.var), !dbg !18
 // CHECK:STDOUT:   %.loc8_4.a = getelementptr inbounds nuw [12 x i8], ptr %x.var, i32 0, i32 0, !dbg !19
 // CHECK:STDOUT:   store i32 1, ptr %.loc8_4.a, align 4, !dbg !19
 // CHECK:STDOUT:   %.loc9_4.b = getelementptr inbounds nuw [12 x i8], ptr %x.var, i32 0, i32 4, !dbg !20
@@ -340,17 +350,32 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT:   ret void, !dbg !23
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_COp:thunk.X.Cpp"(ptr sret([12 x i8]) %return) #5 !dbg !24 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_ZN1XC1Ev.carbon_thunk(ptr %return), !dbg !29
+// CHECK:STDOUT:   ret void, !dbg !29
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #4
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #6
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.64f6b96556a8f2d4"(ptr sret([12 x i8]) %return) #4 !dbg !30 {
+// CHECK:STDOUT:   call void @"_COp:thunk.X.Cpp"(ptr %return), !dbg !32
+// CHECK:STDOUT:   ret void, !dbg !33
+// CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #3 = { nounwind }
-// CHECK:STDOUT: attributes #4 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #4 = { nounwind }
+// CHECK:STDOUT: attributes #5 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #6 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!5}
@@ -380,6 +405,16 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT: !21 = !DILocation(line: 10, column: 3, scope: !15)
 // CHECK:STDOUT: !22 = !DILocation(line: 11, column: 3, scope: !15)
 // CHECK:STDOUT: !23 = !DILocation(line: 6, column: 1, scope: !15)
+// CHECK:STDOUT: !24 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.X.Cpp", scope: null, file: !25, line: 2, type: !26, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !25 = !DIFile(filename: "./struct.h", directory: "")
+// CHECK:STDOUT: !26 = !DISubroutineType(types: !27)
+// CHECK:STDOUT: !27 = !{!28}
+// CHECK:STDOUT: !28 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !29 = !DILocation(line: 2, column: 8, scope: !24)
+// CHECK:STDOUT: !30 = distinct !DISubprogram(name: "Op", linkageName: "_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.64f6b96556a8f2d4", scope: null, file: !31, line: 9, type: !26, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !31 = !DIFile(filename: "min_prelude/parts/default.carbon", directory: "")
+// CHECK:STDOUT: !32 = !DILocation(line: 9, column: 28, scope: !30)
+// CHECK:STDOUT: !33 = !DILocation(line: 9, column: 21, scope: !30)
 // CHECK:STDOUT: ; ModuleID = 'import_class_with_nontrivial_copy.carbon'
 // CHECK:STDOUT: source_filename = "import_class_with_nontrivial_copy.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"

toolchain/lower/testdata/interop/cpp/reference.carbon

@@ -135,8 +135,17 @@ fn GetRefs() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: @C.val.loc19_20.1 = internal constant {} zeroinitializer
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress nounwind uwtable
+// CHECK:STDOUT: define dso_local void @_ZN1CC1Ev.carbon_thunk(ptr noundef %return) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z9TakeCRRefO1C.carbon_thunk(ptr noundef %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z9TakeCRRefO1C.carbon_thunk(ptr noundef %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !11
@@ -145,10 +154,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z9TakeCRRefO1C(ptr noundef nonnull align 1 dereferenceable(1)) #1
+// CHECK:STDOUT: declare void @_Z9TakeCRRefO1C(ptr noundef nonnull align 1 dereferenceable(1)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z13TakeConstCRefRK1C.carbon_thunk(ptr noundef %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z13TakeConstCRefRK1C.carbon_thunk(ptr noundef %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !11
@@ -157,10 +166,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z13TakeConstCRefRK1C(ptr noundef nonnull align 1 dereferenceable(1)) #1
+// CHECK:STDOUT: declare void @_Z13TakeConstCRefRK1C(ptr noundef nonnull align 1 dereferenceable(1)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z11TakeIntRRefOi.carbon_thunk(ptr noundef %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z11TakeIntRRefOi.carbon_thunk(ptr noundef %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !14
@@ -169,10 +178,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z11TakeIntRRefOi(ptr noundef nonnull align 4 dereferenceable(4)) #1
+// CHECK:STDOUT: declare void @_Z11TakeIntRRefOi(ptr noundef nonnull align 4 dereferenceable(4)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z15TakeConstIntRefRKi.carbon_thunk(ptr noundef %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z15TakeConstIntRefRKi.carbon_thunk(ptr noundef %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !14
@@ -181,10 +190,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z15TakeConstIntRefRKi(ptr noundef nonnull align 4 dereferenceable(4)) #1
+// CHECK:STDOUT: declare void @_Z15TakeConstIntRefRKi(ptr noundef nonnull align 4 dereferenceable(4)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassRefs.Main() #2 !dbg !16 {
+// CHECK:STDOUT: define void @_CPassRefs.Main() #3 !dbg !16 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %c.var = alloca {}, align 8, !dbg !19
 // CHECK:STDOUT:   %.loc19_18.2.temp = alloca {}, align 8, !dbg !20
@@ -192,6 +201,7 @@ fn GetRefs() {
 // CHECK:STDOUT:   %.loc24_22.3.temp = alloca i32, align 4, !dbg !22
 // CHECK:STDOUT:   %.loc25_23.2.temp = alloca i32, align 4, !dbg !23
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !19
+// CHECK:STDOUT:   call void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.93349b0fe912a29b"(ptr %c.var), !dbg !19
 // CHECK:STDOUT:   call void @_Z8TakeCRefR1C(ptr %c.var), !dbg !24
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc19_18.2.temp), !dbg !20
 // CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc19_18.2.temp, ptr align 1 @C.val.loc19_20.1, i64 0, i1 false), !dbg !20
@@ -210,24 +220,39 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void, !dbg !30
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z8TakeCRefR1C(ptr noundef nonnull align 1 dereferenceable(1)) #1
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_COp:thunk.C.Cpp"(ptr sret({}) %return) #4 !dbg !31 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_ZN1CC1Ev.carbon_thunk(ptr %return), !dbg !35
+// CHECK:STDOUT:   ret void, !dbg !35
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z8TakeCRefR1C(ptr noundef nonnull align 1 dereferenceable(1)) #2
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z10TakeIntRefRi(ptr noundef nonnull align 4 dereferenceable(4)) #1
+// CHECK:STDOUT: declare void @_Z10TakeIntRefRi(ptr noundef nonnull align 4 dereferenceable(4)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #5
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.93349b0fe912a29b"(ptr sret({}) %return) #3 !dbg !36 {
+// CHECK:STDOUT:   call void @"_COp:thunk.C.Cpp"(ptr %return), !dbg !38
+// CHECK:STDOUT:   ret void, !dbg !39
+// CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #4
+// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #6
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 4, 3, 2, 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { nounwind }
-// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #4 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #3 = { nounwind }
+// CHECK:STDOUT: attributes #4 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #5 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #6 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!5}
@@ -264,6 +289,15 @@ fn GetRefs() {
 // CHECK:STDOUT: !28 = !DILocation(line: 24, column: 3, scope: !16)
 // CHECK:STDOUT: !29 = !DILocation(line: 25, column: 3, scope: !16)
 // CHECK:STDOUT: !30 = !DILocation(line: 16, column: 1, scope: !16)
+// CHECK:STDOUT: !31 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.C.Cpp", scope: null, file: !6, line: 5, type: !32, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !32 = !DISubroutineType(types: !33)
+// CHECK:STDOUT: !33 = !{!34}
+// CHECK:STDOUT: !34 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !35 = !DILocation(line: 5, column: 7, scope: !31)
+// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "Op", linkageName: "_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.93349b0fe912a29b", scope: null, file: !37, line: 9, type: !32, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !37 = !DIFile(filename: "min_prelude/parts/default.carbon", directory: "")
+// CHECK:STDOUT: !38 = !DILocation(line: 9, column: 28, scope: !36)
+// CHECK:STDOUT: !39 = !DILocation(line: 9, column: 21, scope: !36)
 // CHECK:STDOUT: ; ModuleID = 'pass_references_via_thunk.carbon'
 // CHECK:STDOUT: source_filename = "pass_references_via_thunk.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -273,8 +307,17 @@ fn GetRefs() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: @C.val.loc20_20.1 = internal constant {} zeroinitializer
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress nounwind uwtable
+// CHECK:STDOUT: define dso_local void @_ZN1CC1Ev.carbon_thunk(ptr noundef %return) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z8TakeCRefR1C10ForceThunk.carbon_thunk1(ptr noundef nonnull align 1 dereferenceable(1) %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z8TakeCRefR1C10ForceThunk.carbon_thunk1(ptr noundef nonnull align 1 dereferenceable(1) %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
@@ -284,10 +327,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z8TakeCRefR1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #1
+// CHECK:STDOUT: declare void @_Z8TakeCRefR1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z9TakeCRRefRK1C10ForceThunk.carbon_thunk1(ptr noundef %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z9TakeCRRefRK1C10ForceThunk.carbon_thunk1(ptr noundef %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
@@ -297,10 +340,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z9TakeCRRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #1
+// CHECK:STDOUT: declare void @_Z9TakeCRRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z13TakeConstCRefRK1C10ForceThunk.carbon_thunk1(ptr noundef %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z13TakeConstCRefRK1C10ForceThunk.carbon_thunk1(ptr noundef %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
@@ -310,10 +353,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z13TakeConstCRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #1
+// CHECK:STDOUT: declare void @_Z13TakeConstCRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z10TakeIntRefRi10ForceThunk.carbon_thunk1(ptr noundef nonnull align 4 dereferenceable(4) %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z10TakeIntRefRi10ForceThunk.carbon_thunk1(ptr noundef nonnull align 4 dereferenceable(4) %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
@@ -323,10 +366,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z10TakeIntRefRi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #1
+// CHECK:STDOUT: declare void @_Z10TakeIntRefRi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z11TakeIntRRefOi10ForceThunk.carbon_thunk1(ptr noundef %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z11TakeIntRRefOi10ForceThunk.carbon_thunk1(ptr noundef %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
@@ -336,10 +379,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z11TakeIntRRefOi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #1
+// CHECK:STDOUT: declare void @_Z11TakeIntRRefOi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z15TakeConstIntRefRKi10ForceThunk.carbon_thunk1(ptr noundef %0) #0 {
+// CHECK:STDOUT: define dso_local void @_Z15TakeConstIntRefRKi10ForceThunk.carbon_thunk1(ptr noundef %0) #1 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
@@ -349,10 +392,10 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z15TakeConstIntRefRKi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #1
+// CHECK:STDOUT: declare void @_Z15TakeConstIntRefRKi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassRefs.Main() #2 !dbg !18 {
+// CHECK:STDOUT: define void @_CPassRefs.Main() #3 !dbg !18 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %c.var = alloca {}, align 8, !dbg !21
 // CHECK:STDOUT:   %.loc20_18.2.temp = alloca {}, align 8, !dbg !22
@@ -360,6 +403,7 @@ fn GetRefs() {
 // CHECK:STDOUT:   %.loc25_22.3.temp = alloca i32, align 4, !dbg !24
 // CHECK:STDOUT:   %.loc26_23.2.temp = alloca i32, align 4, !dbg !25
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !21
+// CHECK:STDOUT:   call void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.93349b0fe912a29b"(ptr %c.var), !dbg !21
 // CHECK:STDOUT:   call void @_Z8TakeCRefR1C10ForceThunk.carbon_thunk1(ptr %c.var), !dbg !26
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc20_18.2.temp), !dbg !22
 // CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc20_18.2.temp, ptr align 1 @C.val.loc20_20.1, i64 0, i1 false), !dbg !22
@@ -378,20 +422,35 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void, !dbg !32
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_COp:thunk.C.Cpp"(ptr sret({}) %return) #4 !dbg !33 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_ZN1CC1Ev.carbon_thunk(ptr %return), !dbg !37
+// CHECK:STDOUT:   ret void, !dbg !37
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #5
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr void @"_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.93349b0fe912a29b"(ptr sret({}) %return) #3 !dbg !38 {
+// CHECK:STDOUT:   call void @"_COp:thunk.C.Cpp"(ptr %return), !dbg !40
+// CHECK:STDOUT:   ret void, !dbg !41
+// CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #4
+// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #6
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 4, 3, 2, 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { nounwind }
-// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #4 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #3 = { nounwind }
+// CHECK:STDOUT: attributes #4 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #5 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #6 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!5}
@@ -430,6 +489,15 @@ fn GetRefs() {
 // CHECK:STDOUT: !30 = !DILocation(line: 25, column: 3, scope: !18)
 // CHECK:STDOUT: !31 = !DILocation(line: 26, column: 3, scope: !18)
 // CHECK:STDOUT: !32 = !DILocation(line: 17, column: 1, scope: !18)
+// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.C.Cpp", scope: null, file: !6, line: 5, type: !34, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !34 = !DISubroutineType(types: !35)
+// CHECK:STDOUT: !35 = !{!36}
+// CHECK:STDOUT: !36 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !37 = !DILocation(line: 5, column: 7, scope: !33)
+// CHECK:STDOUT: !38 = distinct !DISubprogram(name: "Op", linkageName: "_COp.9b0a46309e124f8a:DefaultOrUnformed.Core.93349b0fe912a29b", scope: null, file: !39, line: 9, type: !34, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !39 = !DIFile(filename: "min_prelude/parts/default.carbon", directory: "")
+// CHECK:STDOUT: !40 = !DILocation(line: 9, column: 28, scope: !38)
+// CHECK:STDOUT: !41 = !DILocation(line: 9, column: 21, scope: !38)
 // CHECK:STDOUT: ; ModuleID = 'return_references.carbon'
 // CHECK:STDOUT: source_filename = "return_references.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"

toolchain/testing/testdata/min_prelude/parts/default.carbon

@@ -8,6 +8,12 @@ package Core library "prelude/parts/default";
 
 interface DefaultOrUnformed { fn Op() -> Self; }
 
+interface Default { fn Op() -> Self; }
+
+final impl forall [T:! Default] T as DefaultOrUnformed {
+  fn Op() -> Self { return T.(Default.Op)(); }
+}
+
 // In tests, just allow any type to be default-initialized as a no-op.
 // TODO: This is a hack to allow existing tests to contiue working.
 impl forall [T:! type] T as DefaultOrUnformed {