Don't create a compile time binding after CompileTimeBindingInVarDecl (#4463)

Related to #4461, more generally try not to produce a compile-time
binding when the code shouldn't be able to do so.

toolchain/check/handle_binding_pattern.cpp

@@ -93,6 +93,8 @@ static auto HandleAnyBindingPattern(Context& context, Parse::NodeId node_id,
             CompileTimeBindingInVarDecl, Error,
             "`var` declaration cannot declare a compile-time binding");
         context.emitter().Emit(type_node, CompileTimeBindingInVarDecl);
+        // Prevent lambda helpers from creating a compile time binding.
+        needs_compile_time_binding = false;
       }
       auto binding_id =
           is_generic

toolchain/check/testdata/function/declaration/no_prelude/fail_todo_no_params.carbon

@@ -51,17 +51,10 @@ library "[[@TEST_NAME]]";
 // CHECK:STDERR:
 var x:! () = ();
 
-// CHECK:STDERR: fail_invalid_file_generic_regression_test.carbon:[[@LINE+4]]:1: error: semantics TODO: `function with positional parameters` [SemanticsTodo]
+// CHECK:STDERR: fail_invalid_file_generic_regression_test.carbon:[[@LINE+3]]:1: error: semantics TODO: `function with positional parameters` [SemanticsTodo]
 // CHECK:STDERR: fn A {
 // CHECK:STDERR: ^~~~~~
-// CHECK:STDERR:
 fn A {
-  // CHECK:STDERR: fail_invalid_file_generic_regression_test.carbon:[[@LINE+6]]:3: error: cannot deduce value for generic parameter `x` [DeductionIncomplete]
-  // CHECK:STDERR:   A();
-  // CHECK:STDERR:   ^~
-  // CHECK:STDERR: fail_invalid_file_generic_regression_test.carbon:[[@LINE-4]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
-  // CHECK:STDERR: fn A {
-  // CHECK:STDERR: ^~~~~~
   A();
 }
 
@@ -123,7 +116,7 @@ fn A {
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
 // CHECK:STDOUT:   %.1: type = tuple_type () [template]
-// CHECK:STDOUT:   %x: %.1 = bind_symbolic_name x, 0 [symbolic]
+// CHECK:STDOUT:   %x: %.1 = bind_symbolic_name x [symbolic]
 // CHECK:STDOUT:   %tuple: %.1 = tuple_value () [template]
 // CHECK:STDOUT:   %A.type: type = fn_type @A [template]
 // CHECK:STDOUT:   %A: %A.type = struct_value () [template]
@@ -137,18 +130,15 @@ fn A {
 // CHECK:STDOUT:   %.loc8_10.1: %.1 = tuple_literal ()
 // CHECK:STDOUT:   %.loc8_10.2: type = converted %.loc8_10.1, constants.%.1 [template = constants.%.1]
 // CHECK:STDOUT:   %x.var: ref %.1 = var x
-// CHECK:STDOUT:   %x: %.1 = bind_symbolic_name x, 0, %x.var [symbolic = constants.%x]
+// CHECK:STDOUT:   %x: %.1 = bind_symbolic_name x, %x.var [symbolic = constants.%x]
 // CHECK:STDOUT:   %A.decl: %A.type = fn_decl @A [template = constants.%A] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: generic fn @A(file.%x: %.1) {
-// CHECK:STDOUT: !definition:
-// CHECK:STDOUT:
-// CHECK:STDOUT:   fn() {
-// CHECK:STDOUT:   !entry:
-// CHECK:STDOUT:     %A.ref: %A.type = name_ref A, file.%A.decl [template = constants.%A]
-// CHECK:STDOUT:     return
-// CHECK:STDOUT:   }
+// CHECK:STDOUT: fn @A() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   %A.ref: %A.type = name_ref A, file.%A.decl [template = constants.%A]
+// CHECK:STDOUT:   %A.call: init %.1 = call %A.ref()
+// CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
@@ -160,5 +150,3 @@ fn A {
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @A(constants.%x) {}
-// CHECK:STDOUT:

toolchain/check/testdata/var/no_prelude/fail_generic.carbon

@@ -21,7 +21,7 @@ fn Main() {
 // CHECK:STDOUT:   %Main.type: type = fn_type @Main [template]
 // CHECK:STDOUT:   %.1: type = tuple_type () [template]
 // CHECK:STDOUT:   %Main: %Main.type = struct_value () [template]
-// CHECK:STDOUT:   %x: %.1 = bind_symbolic_name x, 0 [symbolic]
+// CHECK:STDOUT:   %x: %.1 = bind_symbolic_name x [symbolic]
 // CHECK:STDOUT:   %tuple: %.1 = tuple_value () [template]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -37,7 +37,7 @@ fn Main() {
 // CHECK:STDOUT:   %.loc15_12.1: %.1 = tuple_literal ()
 // CHECK:STDOUT:   %.loc15_12.2: type = converted %.loc15_12.1, constants.%.1 [template = constants.%.1]
 // CHECK:STDOUT:   %x.var: ref %.1 = var x
-// CHECK:STDOUT:   %x: %.1 = bind_symbolic_name x, 0, %x.var [symbolic = constants.%x]
+// CHECK:STDOUT:   %x: %.1 = bind_symbolic_name x, %x.var [symbolic = constants.%x]
 // CHECK:STDOUT:   %.loc15_17.1: %.1 = tuple_literal ()
 // CHECK:STDOUT:   %.loc15_17.2: init %.1 = tuple_init () to %x.var [template = constants.%tuple]
 // CHECK:STDOUT:   %.loc15_18: init %.1 = converted %.loc15_17.1, %.loc15_17.2 [template = constants.%tuple]