carbon-lang/toolchain/check/testdata/facet/period_self.carbon

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/convert.carbon
//
// AUTOUPDATE
// TIP: To test this file alone, run:
// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/facet/period_self.carbon
// TIP: To dump output, run:
// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/facet/period_self.carbon

// --- period_self_param.carbon
library "[[@TEST_NAME]]";

//@dump-sem-ir-begin
interface I(T:! type) {
  let I1:! type;
}

fn F(T:! I(.Self) where .I1 = ()) -> T.I1 {
  return ();
}

fn G(T:! I(.Self as type) where .I1 = ()) -> T.I1 {
  return ();
}
//@dump-sem-ir-end

// --- underscore_identifier_name.carbon
library "[[@TEST_NAME]]";

interface I(T:! type) {
  let I1:! type;
}

// Underscore as the identifier name produces a different parse tree for the
// binding pattern.
fn G(_:! I(.Self) where .I1 = ()) {}

// --- fail_period_self_as_type.carbon
library "[[@TEST_NAME]]";

// TODO: We should diagnose this use of `.Self` directly rather than later when
// it is converted to `type`.
interface I(T:! .Self) {
  // CHECK:STDERR: fail_period_self_as_type.carbon:[[@LINE+7]]:13: error: cannot implicitly convert non-type value of type `.Self` to `type` [ConversionFailureNonTypeToFacet]
  // CHECK:STDERR:   fn G() -> T;
  // CHECK:STDERR:             ^
  // CHECK:STDERR: fail_period_self_as_type.carbon:[[@LINE+4]]:13: note: type `.Self` does not implement interface `Core.ImplicitAs(type)` [MissingImplInMemberAccessNote]
  // CHECK:STDERR:   fn G() -> T;
  // CHECK:STDERR:             ^
  // CHECK:STDERR:
  fn G() -> T;
}

// --- fail_todo_convert_period_self_to_full_facet_value.carbon
library "[[@TEST_NAME]]";

interface I(T:! type) {}

fn F(U:! I(.Self)) {
  // CHECK:STDERR: fail_todo_convert_period_self_to_full_facet_value.carbon:[[@LINE+4]]:3: error: cannot convert type `U` that implements `I(.Self)` into type implementing `I(U)` [ConversionFailureFacetToFacet]
  // CHECK:STDERR:   U as I(U);
  // CHECK:STDERR:   ^~~~~~~~~
  // CHECK:STDERR:
  U as I(U);
  // CHECK:STDERR: fail_todo_convert_period_self_to_full_facet_value.carbon:[[@LINE+4]]:3: error: cannot convert type `U` that implements `I(.Self)` into type implementing `I(U)` [ConversionFailureFacetToFacet]
  // CHECK:STDERR:   (U as type) as I(U);
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  (U as type) as I(U);
}

// --- fail_todo_convert_period_self_to_full_facet_value_with_assoc_constant.carbon
library "[[@TEST_NAME]]";

interface I(T:! type) {
  let X:! type;
}

fn F(U:! I(.Self) where .X = .Self) {
  // CHECK:STDERR: fail_todo_convert_period_self_to_full_facet_value_with_assoc_constant.carbon:[[@LINE+4]]:3: error: cannot convert type `U` that implements `I(.Self) where .(I(.Self).X) = .Self` into type implementing `I(U) where .(I(U).X) = U` [ConversionFailureFacetToFacet]
  // CHECK:STDERR:   U as (I(U) where .X = U);
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  U as (I(U) where .X = U);
  // CHECK:STDERR: fail_todo_convert_period_self_to_full_facet_value_with_assoc_constant.carbon:[[@LINE+4]]:3: error: cannot convert type `U` that implements `I(.Self) where .(I(.Self).X) = .Self` into type implementing `I(U) where .(I(U).X) = U` [ConversionFailureFacetToFacet]
  // CHECK:STDERR:   (U as type) as (I(U) where .X = U);
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  (U as type) as (I(U) where .X = U);
}

// --- fail_todo_return_of_type_period_self.carbon
library "[[@TEST_NAME]]";

interface I(T:! type) {
  fn G() -> T*;
}

interface J(T:! type) {
  fn J1() -> T*;
}

fn F2[U:! I(.Self)](T: U*) {}

fn F(U:! I(.Self)) {
  // Caller sees the returned `.Self` type from `F()` as the full `U`.
  // CHECK:STDERR: fail_todo_return_of_type_period_self.carbon:[[@LINE+4]]:3: error: member name `G` not found [MemberNameNotFound]
  // CHECK:STDERR:   U.G()->G()->G();
  // CHECK:STDERR:   ^~~~~~~~
  // CHECK:STDERR:
  U.G()->G()->G();
  // Conversion to `type` retains access to all of `U`.
  // CHECK:STDERR: fail_todo_return_of_type_period_self.carbon:[[@LINE+4]]:3: error: member name `G` not found [MemberNameNotFound]
  // CHECK:STDERR:   (U as type).G()->G()->G();
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  (U as type).G()->G()->G();

  // Using the returned `.Self` as a facet value works, not just member lookup
  // on its facet type.
  // CHECK:STDERR: fail_todo_return_of_type_period_self.carbon:[[@LINE+4]]:6: error: member name `G` not found [MemberNameNotFound]
  // CHECK:STDERR:   F2(U.G()->G()->G());
  // CHECK:STDERR:      ^~~~~~~~
  // CHECK:STDERR:
  F2(U.G()->G()->G());
}

// --- fail_todo_return_of_type_period_self_extends_interface.carbon
library "[[@TEST_NAME]]";

interface I(T:! type) {
  fn I1() -> T*;
}

interface J(T:! type) {
  fn J1() -> T*;
}

fn F2[U:! I(.Self) & J(.Self)](T: U*) {}

fn F(U:! I(.Self) & J(.Self)) {
  // TODO: The returned value of `I1` and `J1` has type `U` which has access to
  // the methods of `I` and `J`.
  // CHECK:STDERR: fail_todo_return_of_type_period_self_extends_interface.carbon:[[@LINE+4]]:3: error: member name `J1` not found [MemberNameNotFound]
  // CHECK:STDERR:   U.I1()->J1()->I1()->J1()->I1()->J1();
  // CHECK:STDERR:   ^~~~~~~~~~
  // CHECK:STDERR:
  U.I1()->J1()->I1()->J1()->I1()->J1();
  // CHECK:STDERR: fail_todo_return_of_type_period_self_extends_interface.carbon:[[@LINE+4]]:3: error: member name `J1` not found [MemberNameNotFound]
  // CHECK:STDERR:   (U as type).I1()->J1()->I1()->J1()->I1()->J1();
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  (U as type).I1()->J1()->I1()->J1()->I1()->J1();

  // TODO: Using the returned value of type `U` as a facet value works.
  // CHECK:STDERR: fail_todo_return_of_type_period_self_extends_interface.carbon:[[@LINE+4]]:6: error: member name `J1` not found [MemberNameNotFound]
  // CHECK:STDERR:   F2(U.I1()->J1()->I1()->J1()->I1()->J1());
  // CHECK:STDERR:      ^~~~~~~~~~
  // CHECK:STDERR:
  F2(U.I1()->J1()->I1()->J1()->I1()->J1());
}

// --- fail_todo_return_of_period_self_impls_interface.carbon
library "[[@TEST_NAME]]";

interface I(T:! type) {
  fn I1() -> T;
}

interface J(T:! type) {
  fn J1() -> T;
}

fn G(U:! I(.Self) where .Self impls J(.Self)) {
  // Compound member lookup through a non-type value is possible for methods
  // which take a `self` parameter. But it's not possible for methods without
  // `self`. For those you need to go directly throug the type.
  // See: https://github.com/carbon-language/carbon-lang/issues/6025

  // TODO: This step should work.
  //
  // CHECK:STDERR: fail_todo_return_of_period_self_impls_interface.carbon:[[@LINE+7]]:14: error: cannot implicitly convert expression of type `.Self` to `U` [ConversionFailure]
  // CHECK:STDERR:   let u: U = U.I1();
  // CHECK:STDERR:              ^~~~~~
  // CHECK:STDERR: fail_todo_return_of_period_self_impls_interface.carbon:[[@LINE+4]]:14: note: type `.Self` does not implement interface `Core.ImplicitAs(U)` [MissingImplInMemberAccessNote]
  // CHECK:STDERR:   let u: U = U.I1();
  // CHECK:STDERR:              ^~~~~~
  // CHECK:STDERR:
  let u: U = U.I1();
  // `u` is a non-type value. Can call methods with `self` through compound
  // member lookup, but can't call methods without `self`. See the
  // `compound_access_through_call_with_self_param.carbon` test for the former.
  //
  // CHECK:STDERR: fail_todo_return_of_period_self_impls_interface.carbon:[[@LINE+4]]:6: error: type `<type of J>` does not support qualified expressions [QualifiedExprUnsupported]
  // CHECK:STDERR:   u.(J.J1)();
  // CHECK:STDERR:      ^~~~
  // CHECK:STDERR:
  u.(J.J1)();

  // This is the same as the above, since U.I1() returns a non-type value of
  // type `U`.
  //
  // CHECK:STDERR: fail_todo_return_of_period_self_impls_interface.carbon:[[@LINE+4]]:11: error: type `<type of J>` does not support qualified expressions [QualifiedExprUnsupported]
  // CHECK:STDERR:   U.I1().(J.J1)();
  // CHECK:STDERR:           ^~~~
  // CHECK:STDERR:
  U.I1().(J.J1)();
}

// --- fail_todo_return_of_type_period_self_has_type_u.carbon
library "[[@TEST_NAME]]";

interface I(T:! type) {
  fn G() -> T;
}

fn F(U:! I(.Self)) {
  // CHECK:STDERR: fail_todo_return_of_type_period_self_has_type_u.carbon:[[@LINE+7]]:14: error: cannot implicitly convert expression of type `.Self` to `U` [ConversionFailure]
  // CHECK:STDERR:   let a: U = U.G();
  // CHECK:STDERR:              ^~~~~
  // CHECK:STDERR: fail_todo_return_of_type_period_self_has_type_u.carbon:[[@LINE+4]]:14: note: type `.Self` does not implement interface `Core.ImplicitAs(U)` [MissingImplInMemberAccessNote]
  // CHECK:STDERR:   let a: U = U.G();
  // CHECK:STDERR:              ^~~~~
  // CHECK:STDERR:
  let a: U = U.G();
}

// --- fail_todo_return_of_type_period_self_assoc_const_has_type_u.carbon
library "[[@TEST_NAME]]";

interface I {
  let X:! type;
  fn G() -> X;
}

fn F(U:! I where .X = .Self) {
  // CHECK:STDERR: fail_todo_return_of_type_period_self_assoc_const_has_type_u.carbon:[[@LINE+7]]:14: error: cannot implicitly convert expression of type `.Self` to `U` [ConversionFailure]
  // CHECK:STDERR:   let a: U = U.G();
  // CHECK:STDERR:              ^~~~~
  // CHECK:STDERR: fail_todo_return_of_type_period_self_assoc_const_has_type_u.carbon:[[@LINE+4]]:14: note: type `.Self` does not implement interface `Core.ImplicitAs(U)` [MissingImplInMemberAccessNote]
  // CHECK:STDERR:   let a: U = U.G();
  // CHECK:STDERR:              ^~~~~
  // CHECK:STDERR:
  let a: U = U.G();
}

// --- fail_todo_nested_period_self.carbon
library "[[@TEST_NAME]]";

interface I(T:! type) {
  let A:! type;
  let B:! type;
  fn G() -> T;
}

// Both `.Self` refer to `T`. The first because it's the interface for the
// binding. The second because it refers to the top level facet type which is
// constraining the binding.
fn F(T:! I(.Self) where .A = ((I(.Self) where .B = {}) where .A = {}) and .B = {}, U:! T.A) {
  // T.G() has type T.
  // CHECK:STDERR: fail_todo_nested_period_self.carbon:[[@LINE+7]]:14: error: cannot implicitly convert expression of type `.Self` to `T` [ConversionFailure]
  // CHECK:STDERR:   let t: T = T.G();
  // CHECK:STDERR:              ^~~~~
  // CHECK:STDERR: fail_todo_nested_period_self.carbon:[[@LINE+4]]:14: note: type `.Self` does not implement interface `Core.ImplicitAs(T)` [MissingImplInMemberAccessNote]
  // CHECK:STDERR:   let t: T = T.G();
  // CHECK:STDERR:              ^~~~~
  // CHECK:STDERR:
  let t: T = T.G();
    // U.G() has type T.
  // CHECK:STDERR: fail_todo_nested_period_self.carbon:[[@LINE+7]]:14: error: cannot implicitly convert expression of type `.Self` to `T` [ConversionFailure]
  // CHECK:STDERR:   let u: T = U.G();
  // CHECK:STDERR:              ^~~~~
  // CHECK:STDERR: fail_todo_nested_period_self.carbon:[[@LINE+4]]:14: note: type `.Self` does not implement interface `Core.ImplicitAs(T)` [MissingImplInMemberAccessNote]
  // CHECK:STDERR:   let u: T = U.G();
  // CHECK:STDERR:              ^~~~~
  // CHECK:STDERR:
  let u: T = U.G();

  // Shows both `I(.Self)` are `I(T)`.
  // CHECK:STDERR: fail_todo_nested_period_self.carbon:[[@LINE+4]]:9: error: found cycle in facet type constraint for `.(I(T).A)` [FacetTypeConstraintCycle]
  // CHECK:STDERR:   T as (I(T) where .A = (I(T) where .A = {} and .B = {}));
  // CHECK:STDERR:         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  T as (I(T) where .A = (I(T) where .A = {} and .B = {}));
  // CHECK:STDERR: fail_todo_nested_period_self.carbon:[[@LINE+4]]:3: error: cannot convert type `U` that implements `I(.Self) where .(I(.Self).B) = {} and .(I(.Self).A) = {}` into type implementing `I(T) where .(I(T).A) = {} and .(I(T).B) = {}` [ConversionFailureFacetToFacet]
  // CHECK:STDERR:   U as (I(T) where .A = {} and .B = {});
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  U as (I(T) where .A = {} and .B = {});
}

// --- todo_fail_nested_period_self_ambiguous.carbon
library "[[@TEST_NAME]]";

interface I(T:! type) {
  let A:! type;
}

// TODO: This should be an error: The third `.Self` becomes is not able to be
// bound to anything unambiguous here, as it could refer to `T` or to something
// later being constrained by `T.A`.
fn F(T:! I(.Self) where .A = (I(.Self) where .A = I(.Self))) {}


// --- period_self_parameter_sees_lhs_of_where_expr.carbon
library "[[@TEST_NAME]]";

interface I(T:! Core.Destroy) {}

// The `.Self` can see the LHS of the `where` to know `U` impls Core.Destroy.
fn F(U:! Core.Destroy where .Self impls I(.Self)) {}

// --- fail_todo_period_self_parameter_constraint_satisfied_with_type_and.carbon
library "[[@TEST_NAME]]";

interface I(T:! Core.Destroy) {}

// TODO: Implied constraints that `.Self` impls `Core.Destroy` are satisfied by
// the `&` expression.
//
// CHECK:STDERR: fail_todo_period_self_parameter_constraint_satisfied_with_type_and.carbon:[[@LINE+7]]:25: error: cannot convert type `.Self` that implements `type` into type implementing `Core.Destroy` [ConversionFailureFacetToFacet]
// CHECK:STDERR: fn F(U:! Core.Destroy & I(.Self)) {}
// CHECK:STDERR:                         ^~~~~~~~
// CHECK:STDERR: fail_todo_period_self_parameter_constraint_satisfied_with_type_and.carbon:[[@LINE-8]]:13: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: interface I(T:! Core.Destroy) {}
// CHECK:STDERR:             ^
// CHECK:STDERR:
fn F(U:! Core.Destroy & I(.Self)) {}

// --- fail_todo_compound_lookup_on_returned_period_self_parameter.carbon
library "[[@TEST_NAME]]";

interface I(T:! Core.Destroy) {
  fn G[self: Self]() -> T;
}

fn F[U:! Core.Destroy where .Self impls I(.Self)](u: U) {
  // This tests that both `I.G` is accessible and that `Destroy` is preserved;
  // we'd get an error for missing Destroy otherwise since G() returns an
  // initializing expression.

  // CHECK:STDERR: fail_todo_compound_lookup_on_returned_period_self_parameter.carbon:[[@LINE+4]]:3: error: cannot access member of interface `I(U as Core.Destroy)` in type `U` that does not implement that interface [MissingImplInMemberAccess]
  // CHECK:STDERR:   u.(I(U).G)().(I(U).G)().(I(U).G)();
  // CHECK:STDERR:   ^~~~~~~~~~
  // CHECK:STDERR:
  u.(I(U).G)().(I(U).G)().(I(U).G)();
}

// CHECK:STDOUT: --- period_self_param.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT:   %type: type = facet_type <type> [concrete]
// CHECK:STDOUT:   %.Self.659: %type = bind_symbolic_name .Self [symbolic_self]
// CHECK:STDOUT:   %T.8b3: type = bind_symbolic_name T, 0 [symbolic]
// CHECK:STDOUT:   %pattern_type.98f: type = pattern_type type [concrete]
// CHECK:STDOUT:   %I.type.dac: type = generic_interface_type @I [concrete]
// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
// CHECK:STDOUT:   %I.generic: %I.type.dac = struct_value () [concrete]
// CHECK:STDOUT:   %I.type.b13: type = facet_type <@I, @I(%T.8b3)> [symbolic]
// CHECK:STDOUT:   %Self.dae: %I.type.b13 = bind_symbolic_name Self, 1 [symbolic]
// CHECK:STDOUT:   %I.assoc_type.1e5: type = assoc_entity_type @I, @I(%T.8b3) [symbolic]
// CHECK:STDOUT:   %assoc0.ab0: %I.assoc_type.1e5 = assoc_entity element0, @I.%I1 [symbolic]
// CHECK:STDOUT:   %.Self.binding.as_type.373: type = symbolic_binding_type .Self, %.Self.659 [symbolic_self]
// CHECK:STDOUT:   %I.type.986: type = facet_type <@I, @I(%.Self.binding.as_type.373)> [symbolic_self]
// CHECK:STDOUT:   %.Self.955: %I.type.986 = bind_symbolic_name .Self [symbolic_self]
// CHECK:STDOUT:   %Self.f35: %I.type.986 = bind_symbolic_name Self, 1 [symbolic]
// CHECK:STDOUT:   %I.assoc_type.4e2: type = assoc_entity_type @I, @I(%.Self.binding.as_type.373) [symbolic_self]
// CHECK:STDOUT:   %assoc0.7d3: %I.assoc_type.4e2 = assoc_entity element0, @I.%I1 [symbolic_self]
// CHECK:STDOUT:   %.Self.binding.as_type.320: type = symbolic_binding_type .Self, %.Self.955 [symbolic_self]
// CHECK:STDOUT:   %I.lookup_impl_witness.462: <witness> = lookup_impl_witness %.Self.955, @I, @I(%.Self.binding.as_type.373) [symbolic_self]
// CHECK:STDOUT:   %impl.elem0: type = impl_witness_access %I.lookup_impl_witness.462, element0 [symbolic_self]
// CHECK:STDOUT:   %I_where.type: type = facet_type <@I, @I(%.Self.binding.as_type.373) where %impl.elem0 = %empty_tuple.type> [symbolic_self]
// CHECK:STDOUT:   %T.797: %I_where.type = bind_symbolic_name T, 0 [symbolic]
// CHECK:STDOUT:   %pattern_type.85a: type = pattern_type %I_where.type [symbolic_self]
// CHECK:STDOUT:   %T.binding.as_type: type = symbolic_binding_type T, 0, %T.797 [symbolic]
// CHECK:STDOUT:   %I.lookup_impl_witness.920: <witness> = lookup_impl_witness %T.797, @I, @I(%.Self.binding.as_type.373) [symbolic]
// CHECK:STDOUT:   %I.facet: %I.type.986 = facet_value %T.binding.as_type, (%I.lookup_impl_witness.920) [symbolic]
// CHECK:STDOUT:   %pattern_type.cb1: type = pattern_type %empty_tuple.type [concrete]
// CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
// CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
// CHECK:STDOUT:   %G.type: type = fn_type @G [concrete]
// CHECK:STDOUT:   %G: %G.type = struct_value () [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: imports {
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: file {
// CHECK:STDOUT:   %I.decl: %I.type.dac = interface_decl @I [concrete = constants.%I.generic] {
// CHECK:STDOUT:     %T.patt: %pattern_type.98f = symbolic_binding_pattern T, 0 [concrete]
// CHECK:STDOUT:   } {
// CHECK:STDOUT:     <elided>
// CHECK:STDOUT:     %T.loc4_13.2: type = bind_symbolic_name T, 0 [symbolic = %T.loc4_13.1 (constants.%T.8b3)]
// CHECK:STDOUT:   }
// CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
// CHECK:STDOUT:     %T.patt: %pattern_type.85a = symbolic_binding_pattern T, 0 [concrete]
// CHECK:STDOUT:     %return.patt: %pattern_type.cb1 = return_slot_pattern [concrete]
// CHECK:STDOUT:     %return.param_patt: %pattern_type.cb1 = out_param_pattern %return.patt, call_param0 [concrete]
// CHECK:STDOUT:   } {
// CHECK:STDOUT:     %T.ref: %I_where.type = name_ref T, %T.loc8_6.2 [symbolic = %T.loc8_6.1 (constants.%T.797)]
// CHECK:STDOUT:     %.loc8_39.1: %I.assoc_type.4e2 = specific_constant @I1.%assoc0, @I(constants.%.Self.binding.as_type.373) [symbolic_self = constants.%assoc0.7d3]
// CHECK:STDOUT:     %I1.ref.loc8_39: %I.assoc_type.4e2 = name_ref I1, %.loc8_39.1 [symbolic_self = constants.%assoc0.7d3]
// CHECK:STDOUT:     %T.as_type: type = facet_access_type %T.ref [symbolic = %T.binding.as_type (constants.%T.binding.as_type)]
// CHECK:STDOUT:     %.loc8_39.2: type = converted %T.ref, %T.as_type [symbolic = %T.binding.as_type (constants.%T.binding.as_type)]
// CHECK:STDOUT:     %impl.elem0.loc8_39: type = impl_witness_access constants.%I.lookup_impl_witness.920, element0 [concrete = constants.%empty_tuple.type]
// CHECK:STDOUT:     %.loc8_19.1: type = splice_block %.loc8_19.2 [symbolic_self = constants.%I_where.type] {
// CHECK:STDOUT:       <elided>
// CHECK:STDOUT:       %I.ref: %I.type.dac = name_ref I, file.%I.decl [concrete = constants.%I.generic]
// CHECK:STDOUT:       %.Self.ref.loc8_12: %type = name_ref .Self, %.Self.1 [symbolic_self = constants.%.Self.659]
// CHECK:STDOUT:       %.Self.as_type.loc8_17: type = facet_access_type %.Self.ref.loc8_12 [symbolic_self = constants.%.Self.binding.as_type.373]
// CHECK:STDOUT:       %.loc8_17: type = converted %.Self.ref.loc8_12, %.Self.as_type.loc8_17 [symbolic_self = constants.%.Self.binding.as_type.373]
// CHECK:STDOUT:       %I.type: type = facet_type <@I, @I(constants.%.Self.binding.as_type.373)> [symbolic_self = constants.%I.type.986]
// CHECK:STDOUT:       <elided>
// CHECK:STDOUT:       %.Self.ref.loc8_25: %I.type.986 = name_ref .Self, %.Self.2 [symbolic_self = constants.%.Self.955]
// CHECK:STDOUT:       %.loc8_25.1: %I.assoc_type.4e2 = specific_constant @I1.%assoc0, @I(constants.%.Self.binding.as_type.373) [symbolic_self = constants.%assoc0.7d3]
// CHECK:STDOUT:       %I1.ref.loc8_25: %I.assoc_type.4e2 = name_ref I1, %.loc8_25.1 [symbolic_self = constants.%assoc0.7d3]
// CHECK:STDOUT:       %.Self.as_type.loc8_25: type = facet_access_type %.Self.ref.loc8_25 [symbolic_self = constants.%.Self.binding.as_type.320]
// CHECK:STDOUT:       %.loc8_25.2: type = converted %.Self.ref.loc8_25, %.Self.as_type.loc8_25 [symbolic_self = constants.%.Self.binding.as_type.320]
// CHECK:STDOUT:       %impl.elem0.loc8_25: type = impl_witness_access constants.%I.lookup_impl_witness.462, element0 [symbolic_self = constants.%impl.elem0]
// CHECK:STDOUT:       %.loc8_32.1: %empty_tuple.type = tuple_literal ()
// CHECK:STDOUT:       %.loc8_32.2: type = converted %.loc8_32.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
// CHECK:STDOUT:       %.loc8_19.2: type = where_expr %.Self.2 [symbolic_self = constants.%I_where.type] {
// CHECK:STDOUT:         requirement_base_facet_type constants.%I.type.986
// CHECK:STDOUT:         requirement_rewrite %impl.elem0.loc8_25, %.loc8_32.2
// CHECK:STDOUT:       }
// CHECK:STDOUT:     }
// CHECK:STDOUT:     %T.loc8_6.2: %I_where.type = bind_symbolic_name T, 0 [symbolic = %T.loc8_6.1 (constants.%T.797)]
// CHECK:STDOUT:     %return.param: ref %empty_tuple.type = out_param call_param0
// CHECK:STDOUT:     %return: ref %empty_tuple.type = return_slot %return.param
// CHECK:STDOUT:   }
// CHECK:STDOUT:   %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {
// CHECK:STDOUT:     %T.patt: %pattern_type.85a = symbolic_binding_pattern T, 0 [concrete]
// CHECK:STDOUT:     %return.patt: %pattern_type.cb1 = return_slot_pattern [concrete]
// CHECK:STDOUT:     %return.param_patt: %pattern_type.cb1 = out_param_pattern %return.patt, call_param0 [concrete]
// CHECK:STDOUT:   } {
// CHECK:STDOUT:     %T.ref: %I_where.type = name_ref T, %T.loc12_6.2 [symbolic = %T.loc12_6.1 (constants.%T.797)]
// CHECK:STDOUT:     %.loc12_47.1: %I.assoc_type.4e2 = specific_constant @I1.%assoc0, @I(constants.%.Self.binding.as_type.373) [symbolic_self = constants.%assoc0.7d3]
// CHECK:STDOUT:     %I1.ref.loc12_47: %I.assoc_type.4e2 = name_ref I1, %.loc12_47.1 [symbolic_self = constants.%assoc0.7d3]
// CHECK:STDOUT:     %T.as_type: type = facet_access_type %T.ref [symbolic = %T.binding.as_type (constants.%T.binding.as_type)]
// CHECK:STDOUT:     %.loc12_47.2: type = converted %T.ref, %T.as_type [symbolic = %T.binding.as_type (constants.%T.binding.as_type)]
// CHECK:STDOUT:     %impl.elem0.loc12_47: type = impl_witness_access constants.%I.lookup_impl_witness.920, element0 [concrete = constants.%empty_tuple.type]
// CHECK:STDOUT:     %.loc12_27.1: type = splice_block %.loc12_27.2 [symbolic_self = constants.%I_where.type] {
// CHECK:STDOUT:       <elided>
// CHECK:STDOUT:       %I.ref: %I.type.dac = name_ref I, file.%I.decl [concrete = constants.%I.generic]
// CHECK:STDOUT:       %.Self.ref.loc12_12: %type = name_ref .Self, %.Self.1 [symbolic_self = constants.%.Self.659]
// CHECK:STDOUT:       %.Self.as_type.loc12_18: type = facet_access_type %.Self.ref.loc12_12 [symbolic_self = constants.%.Self.binding.as_type.373]
// CHECK:STDOUT:       %.loc12_18: type = converted %.Self.ref.loc12_12, %.Self.as_type.loc12_18 [symbolic_self = constants.%.Self.binding.as_type.373]
// CHECK:STDOUT:       %I.type: type = facet_type <@I, @I(constants.%.Self.binding.as_type.373)> [symbolic_self = constants.%I.type.986]
// CHECK:STDOUT:       <elided>
// CHECK:STDOUT:       %.Self.ref.loc12_33: %I.type.986 = name_ref .Self, %.Self.2 [symbolic_self = constants.%.Self.955]
// CHECK:STDOUT:       %.loc12_33.1: %I.assoc_type.4e2 = specific_constant @I1.%assoc0, @I(constants.%.Self.binding.as_type.373) [symbolic_self = constants.%assoc0.7d3]
// CHECK:STDOUT:       %I1.ref.loc12_33: %I.assoc_type.4e2 = name_ref I1, %.loc12_33.1 [symbolic_self = constants.%assoc0.7d3]
// CHECK:STDOUT:       %.Self.as_type.loc12_33: type = facet_access_type %.Self.ref.loc12_33 [symbolic_self = constants.%.Self.binding.as_type.320]
// CHECK:STDOUT:       %.loc12_33.2: type = converted %.Self.ref.loc12_33, %.Self.as_type.loc12_33 [symbolic_self = constants.%.Self.binding.as_type.320]
// CHECK:STDOUT:       %impl.elem0.loc12_33: type = impl_witness_access constants.%I.lookup_impl_witness.462, element0 [symbolic_self = constants.%impl.elem0]
// CHECK:STDOUT:       %.loc12_40.1: %empty_tuple.type = tuple_literal ()
// CHECK:STDOUT:       %.loc12_40.2: type = converted %.loc12_40.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
// CHECK:STDOUT:       %.loc12_27.2: type = where_expr %.Self.2 [symbolic_self = constants.%I_where.type] {
// CHECK:STDOUT:         requirement_base_facet_type constants.%I.type.986
// CHECK:STDOUT:         requirement_rewrite %impl.elem0.loc12_33, %.loc12_40.2
// CHECK:STDOUT:       }
// CHECK:STDOUT:     }
// CHECK:STDOUT:     %T.loc12_6.2: %I_where.type = bind_symbolic_name T, 0 [symbolic = %T.loc12_6.1 (constants.%T.797)]
// CHECK:STDOUT:     %return.param: ref %empty_tuple.type = out_param call_param0
// CHECK:STDOUT:     %return: ref %empty_tuple.type = return_slot %return.param
// CHECK:STDOUT:   }
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: generic interface @I(%T.loc4_13.2: type) {
// CHECK:STDOUT:   %T.loc4_13.1: type = bind_symbolic_name T, 0 [symbolic = %T.loc4_13.1 (constants.%T.8b3)]
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT:   <elided>
// CHECK:STDOUT:   %I.assoc_type: type = assoc_entity_type @I, @I(%T.loc4_13.1) [symbolic = %I.assoc_type (constants.%I.assoc_type.1e5)]
// CHECK:STDOUT:   %assoc0: @I.%I.assoc_type (%I.assoc_type.1e5) = assoc_entity element0, %I1 [symbolic = %assoc0 (constants.%assoc0.ab0)]
// CHECK:STDOUT:
// CHECK:STDOUT:   interface {
// CHECK:STDOUT:     <elided>
// CHECK:STDOUT:     %I1: type = assoc_const_decl @I1 [concrete] {
// CHECK:STDOUT:       %assoc0: @I.%I.assoc_type (%I.assoc_type.1e5) = assoc_entity element0, @I.%I1 [symbolic = @I.%assoc0 (constants.%assoc0.ab0)]
// CHECK:STDOUT:     }
// CHECK:STDOUT:
// CHECK:STDOUT:   !members:
// CHECK:STDOUT:     .Self = %Self.1
// CHECK:STDOUT:     .I1 = @I1.%assoc0
// CHECK:STDOUT:     witness = (%I1)
// CHECK:STDOUT:   }
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: generic assoc_const @I1(@I.%T.loc4_13.2: type, @I.%Self.1: @I.%I.type (%I.type.b13)) {
// CHECK:STDOUT:   assoc_const I1:! type;
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: generic fn @F(%T.loc8_6.2: %I_where.type) {
// CHECK:STDOUT:   %T.loc8_6.1: %I_where.type = bind_symbolic_name T, 0 [symbolic = %T.loc8_6.1 (constants.%T.797)]
// CHECK:STDOUT:   %T.binding.as_type: type = symbolic_binding_type T, 0, %T.loc8_6.1 [symbolic = %T.binding.as_type (constants.%T.binding.as_type)]
// CHECK:STDOUT:   %I.lookup_impl_witness: <witness> = lookup_impl_witness %T.loc8_6.1, @I, @I(constants.%.Self.binding.as_type.373) [symbolic = %I.lookup_impl_witness (constants.%I.lookup_impl_witness.920)]
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT:
// CHECK:STDOUT:   fn() -> %empty_tuple.type {
// CHECK:STDOUT:   !entry:
// CHECK:STDOUT:     %.loc9_11.1: %empty_tuple.type = tuple_literal ()
// CHECK:STDOUT:     %.loc9_11.2: init %empty_tuple.type = tuple_init () to %return [concrete = constants.%empty_tuple]
// CHECK:STDOUT:     %.loc9_12: init %empty_tuple.type = converted %.loc9_11.1, %.loc9_11.2 [concrete = constants.%empty_tuple]
// CHECK:STDOUT:     return %.loc9_12 to %return
// CHECK:STDOUT:   }
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: generic fn @G(%T.loc12_6.2: %I_where.type) {
// CHECK:STDOUT:   %T.loc12_6.1: %I_where.type = bind_symbolic_name T, 0 [symbolic = %T.loc12_6.1 (constants.%T.797)]
// CHECK:STDOUT:   %T.binding.as_type: type = symbolic_binding_type T, 0, %T.loc12_6.1 [symbolic = %T.binding.as_type (constants.%T.binding.as_type)]
// CHECK:STDOUT:   %I.lookup_impl_witness: <witness> = lookup_impl_witness %T.loc12_6.1, @I, @I(constants.%.Self.binding.as_type.373) [symbolic = %I.lookup_impl_witness (constants.%I.lookup_impl_witness.920)]
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT:
// CHECK:STDOUT:   fn() -> %empty_tuple.type {
// CHECK:STDOUT:   !entry:
// CHECK:STDOUT:     %.loc13_11.1: %empty_tuple.type = tuple_literal ()
// CHECK:STDOUT:     %.loc13_11.2: init %empty_tuple.type = tuple_init () to %return [concrete = constants.%empty_tuple]
// CHECK:STDOUT:     %.loc13_12: init %empty_tuple.type = converted %.loc13_11.1, %.loc13_11.2 [concrete = constants.%empty_tuple]
// CHECK:STDOUT:     return %.loc13_12 to %return
// CHECK:STDOUT:   }
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @I(constants.%T.8b3) {
// CHECK:STDOUT:   %T.loc4_13.1 => constants.%T.8b3
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @I1(constants.%T.8b3, constants.%Self.dae) {}
// CHECK:STDOUT:
// CHECK:STDOUT: specific @I(constants.%.Self.binding.as_type.373) {
// CHECK:STDOUT:   %T.loc4_13.1 => constants.%.Self.binding.as_type.373
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT:   %I.type => constants.%I.type.986
// CHECK:STDOUT:   %Self.2 => constants.%Self.f35
// CHECK:STDOUT:   %I.assoc_type => constants.%I.assoc_type.4e2
// CHECK:STDOUT:   %assoc0 => constants.%assoc0.7d3
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @I1(constants.%.Self.binding.as_type.373, constants.%.Self.955) {}
// CHECK:STDOUT:
// CHECK:STDOUT: specific @I1(constants.%.Self.binding.as_type.373, constants.%I.facet) {}
// CHECK:STDOUT:
// CHECK:STDOUT: specific @F(constants.%T.797) {
// CHECK:STDOUT:   %T.loc8_6.1 => constants.%T.797
// CHECK:STDOUT:   %T.binding.as_type => constants.%T.binding.as_type
// CHECK:STDOUT:   %I.lookup_impl_witness => constants.%I.lookup_impl_witness.920
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @G(constants.%T.797) {
// CHECK:STDOUT:   %T.loc12_6.1 => constants.%T.797
// CHECK:STDOUT:   %T.binding.as_type => constants.%T.binding.as_type
// CHECK:STDOUT:   %I.lookup_impl_witness => constants.%I.lookup_impl_witness.920
// CHECK:STDOUT: }
// CHECK:STDOUT: