Add a bit more structure to interop/cpp tests. (#7085)

Add import/ and export/ under function/. Move most top-level tests to a
new basics/ with subdirectories for `import` directives and `inline
Cpp`. Add subdirectory for primitive type handling. Move all `reverse/`
tests to somewhere else, typically under an `export/` directory.

I split two test files up: constexpr.carbon got split into var/ and
function/ pieces, and reverse/simple.carbon was inlined into
namespace/export.carbon. The rest are just simple renames.

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

@@ -0,0 +1,122 @@
+// 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/int.carbon
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/export/function.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/export/function.carbon
+
+// --- other.carbon
+
+package Other;
+fn F1() {}
+fn F2() -> i32 { return 0; }
+fn F3(_: i32) {}
+
+fn HasGenericArg(T:! type, a: T) { a; }
+fn HasDeducedArg[T:! type](a: T) { a; }
+
+class C {
+  fn Method[self: Self]() { self; }
+}
+
+// --- function.carbon
+
+library "[[@TEST_NAME]]";
+
+import Other;
+import Cpp inline '''
+void G() {
+  Carbon::Other::F1();
+}
+''';
+
+// --- return_int.carbon
+
+library "[[@TEST_NAME]]";
+
+import Other;
+import Cpp inline '''
+int G() {
+  return Carbon::Other::F2();
+}
+''';
+
+// --- args.carbon
+
+library "[[@TEST_NAME]]";
+
+import Other;
+import Cpp inline '''
+void G() {
+  Carbon::Other::F3(123);
+}
+''';
+
+// --- fail_todo_generic.carbon
+
+library "[[@TEST_NAME]]";
+
+// CHECK:STDERR: fail_todo_generic.carbon:[[@LINE+5]]:1: in import [InImport]
+// CHECK:STDERR: other.carbon:7:1: error: semantics TODO: `unsupported: C++ calling a Carbon function with generic parameters` [SemanticsTodo]
+// CHECK:STDERR: fn HasGenericArg(T:! type, a: T) { a; }
+// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR:
+import Other;
+import Cpp inline '''
+void G() {
+  // CHECK:STDERR: fail_todo_generic.carbon:[[@LINE+8]]:18: error: no member named 'HasGenericArg' in namespace 'Carbon::Other' [CppInteropParseError]
+  // CHECK:STDERR:    20 |   Carbon::Other::HasGenericArg<int>(123);
+  // CHECK:STDERR:       |                  ^~~~~~~~~~~~~
+  // CHECK:STDERR:
+  // CHECK:STDERR: fail_todo_generic.carbon:[[@LINE+4]]:35: error: expected '(' for function-style cast or type construction [CppInteropParseError]
+  // CHECK:STDERR:    20 |   Carbon::Other::HasGenericArg<int>(123);
+  // CHECK:STDERR:       |                                ~~~^
+  // CHECK:STDERR:
+  Carbon::Other::HasGenericArg<int>(123);
+}
+''';
+
+// --- fail_todo_deduced.carbon
+
+library "[[@TEST_NAME]]";
+
+// CHECK:STDERR: fail_todo_deduced.carbon:[[@LINE+5]]:1: in import [InImport]
+// CHECK:STDERR: other.carbon:8:1: error: semantics TODO: `unsupported: C++ calling a Carbon function with generic parameters` [SemanticsTodo]
+// CHECK:STDERR: fn HasDeducedArg[T:! type](a: T) { a; }
+// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR:
+import Other;
+import Cpp inline '''
+void G() {
+  // CHECK:STDERR: fail_todo_deduced.carbon:[[@LINE+4]]:18: error: no member named 'HasDeducedArg' in namespace 'Carbon::Other' [CppInteropParseError]
+  // CHECK:STDERR:    16 |   Carbon::Other::HasDeducedArg(123);
+  // CHECK:STDERR:       |                  ^~~~~~~~~~~~~
+  // CHECK:STDERR:
+  Carbon::Other::HasDeducedArg(123);
+}
+''';
+
+// --- fail_todo_method.carbon
+
+library "[[@TEST_NAME]]";
+
+// CHECK:STDERR: fail_todo_method.carbon:[[@LINE+5]]:1: in import [InImport]
+// CHECK:STDERR: other.carbon:11:3: error: semantics TODO: `unsupported: C++ calling a Carbon function with an implicit parameter` [SemanticsTodo]
+// CHECK:STDERR:   fn Method[self: Self]() { self; }
+// CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR:
+import Other;
+import Cpp inline '''
+void G() {
+  // CHECK:STDERR: fail_todo_method.carbon:[[@LINE+4]]:22: error: no member named 'Method' in 'Carbon::Other::C' [CppInteropParseError]
+  // CHECK:STDERR:    16 |   Carbon::Other::C().Method();
+  // CHECK:STDERR:       |   ~~~~~~~~~~~~~~~~~~ ^
+  // CHECK:STDERR:
+  Carbon::Other::C().Method();
+}
+''';

toolchain/check/testdata/interop/cpp/function/export/thunk_ast.carbon

@@ -0,0 +1,55 @@
+// 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/int.carbon
+// EXTRA-ARGS: --dump-cpp-ast
+// SET-CHECK-SUBSET
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/export/thunk_ast.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/export/thunk_ast.carbon
+// CHECK:STDOUT: TranslationUnitDecl {{0x[a-f0-9]+}} <<invalid sloc>> <invalid sloc>
+// CHECK:STDOUT: |-NamespaceDecl {{0x[a-f0-9]+}} <<invalid sloc>> <invalid sloc> Carbon
+
+// --- thunk_with_args_and_return.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp;
+
+fn F(i: i32) -> i32 {
+// CHECK:STDOUT: | `-FunctionDecl {{0x[a-f0-9]+}} <thunk_with_args_and_return.carbon:[[@LINE-1]]:21> col:21 used F__cpp_thunk 'int (int)' inline
+// CHECK:STDOUT: |   |-ParmVarDecl {{0x[a-f0-9]+}} <col:21> col:21 used 'int'
+// CHECK:STDOUT: |   |-CompoundStmt {{0x[a-f0-9]+}} <col:21>
+// CHECK:STDOUT: |   | |-DeclStmt {{0x[a-f0-9]+}} <col:21>
+// CHECK:STDOUT: |   | | `-VarDecl {{0x[a-f0-9]+}} <col:21> col:21 used return_storage 'int' nrvo
+// CHECK:STDOUT: |   | |-CallExpr {{0x[a-f0-9]+}} <col:21> 'void'
+// CHECK:STDOUT: |   | | |-ImplicitCastExpr {{0x[a-f0-9]+}} <col:21> 'void (*)(int &, int &)' <FunctionToPointerDecay>
+// CHECK:STDOUT: |   | | | `-DeclRefExpr {{0x[a-f0-9]+}} <col:21> 'void (int &, int &)' Function {{0x[a-f0-9]+}} 'F__carbon_thunk' 'void (int &, int &)'
+// CHECK:STDOUT: |   | | |-DeclRefExpr {{0x[a-f0-9]+}} <col:21> 'int' lvalue ParmVar {{0x[a-f0-9]+}} depth 0 index 0 'int'
+// CHECK:STDOUT: |   | | `-DeclRefExpr {{0x[a-f0-9]+}} <col:21> 'int' lvalue Var {{0x[a-f0-9]+}} 'return_storage' 'int'
+// CHECK:STDOUT: |   | `-ReturnStmt {{0x[a-f0-9]+}} <col:21> nrvo_candidate(Var {{0x[a-f0-9]+}} 'return_storage' 'int')
+// CHECK:STDOUT: |   |   `-DeclRefExpr {{0x[a-f0-9]+}} <col:21> 'int' lvalue Var {{0x[a-f0-9]+}} 'return_storage' 'int'
+// CHECK:STDOUT: |   |-AlwaysInlineAttr {{0x[a-f0-9]+}} <<invalid sloc>> Implicit always_inline
+// CHECK:STDOUT: |   `-InternalLinkageAttr {{0x[a-f0-9]+}} <<invalid sloc>> Implicit
+// CHECK:STDOUT: `-FunctionDecl {{0x[a-f0-9]+}} <line:35:1, line:37:1> line:35:5 G 'int (int)'
+// CHECK:STDOUT:   |-ParmVarDecl {{0x[a-f0-9]+}} <col:7, col:11> col:11 used i 'int'
+// CHECK:STDOUT:   `-CompoundStmt {{0x[a-f0-9]+}} <col:14, line:37:1>
+// CHECK:STDOUT:     `-ReturnStmt {{0x[a-f0-9]+}} <line:36:3, col:21>
+// CHECK:STDOUT:       `-CallExpr {{0x[a-f0-9]+}} <col:10, col:21> 'int'
+// CHECK:STDOUT:         |-ImplicitCastExpr {{0x[a-f0-9]+}} <col:10, col:18> 'int (*)(int)' <FunctionToPointerDecay>
+// CHECK:STDOUT:         | `-DeclRefExpr {{0x[a-f0-9]+}} <col:10, col:18> 'int (int)' lvalue Function {{0x[a-f0-9]+}} 'F__cpp_thunk' 'int (int)'
+// CHECK:STDOUT:         |   `-NestedNameSpecifier Namespace {{0x[a-f0-9]+}} 'Carbon'
+// CHECK:STDOUT:         `-ImplicitCastExpr {{0x[a-f0-9]+}} <col:20> 'int' <LValueToRValue>
+// CHECK:STDOUT:           `-DeclRefExpr {{0x[a-f0-9]+}} <col:20> 'int' lvalue ParmVar {{0x[a-f0-9]+}} 'i' 'int'
+  return i;
+}
+
+inline Cpp '''
+int G(int i) {
+  return Carbon::F(i);
+}
+''';

toolchain/check/testdata/interop/cpp/function/import/arithmetic_types_bridged.carbon

@@ -7,9 +7,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/arithmetic_types_bridged.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/arithmetic_types_bridged.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/arithmetic_types_bridged.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/arithmetic_types_bridged.carbon
 
 // Tests for the case where we need a thunk when calling a C++ function from
 // Carbon, because the parameter and return types might have a non-trivial

toolchain/check/testdata/interop/cpp/function/import/arithmetic_types_direct.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/arithmetic_types_direct.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/arithmetic_types_direct.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/arithmetic_types_direct.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/arithmetic_types_direct.carbon
 
 // Tests for the case where we can directly call a C++ function from Carbon,
 // because the parameter and return types are known to have a sufficiently

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

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/class.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/class.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/class.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/class.carbon
 
 // ============================================================================
 // Forward-declared class as parameter type

toolchain/check/testdata/interop/cpp/function/import/constexpr.carbon

@@ -0,0 +1,129 @@
+// 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/full.carbon
+// EXTRA-ARGS: --clang-arg=--std=c++20
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/constexpr.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/constexpr.carbon
+
+// --- basic.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp inline '''
+constexpr int f(int a, int b) { return a + b; }
+''';
+
+let a: array(i32, Cpp.f(1, 2)) = (1, 2, 3);
+
+// --- bool_param.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp inline '''
+constexpr int f(bool b) {
+  return b ? 3 : 0;
+}
+''';
+
+let a: array(i32, Cpp.f(true)) = (1, 2, 3);
+
+// --- float_param.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp inline '''
+constexpr int f(float b) {
+  return static_cast<int>(b);
+}
+''';
+
+let a: array(i32, Cpp.f(3.0)) = (1, 2, 3);
+
+// --- return_bool.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp inline '''
+constexpr bool f() {
+  return true;
+}
+''';
+
+musteval fn F(b: bool) -> i32 {
+  return if b then 3 else 0;
+}
+
+let a: array(i32, F(Cpp.f())) = (1, 2, 3);
+
+// --- fail_invalid_constant_eval.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp inline '''
+constexpr int arr[1] = {0};
+constexpr int f(int a) {
+  return arr[a];
+}
+''';
+
+// CHECK:STDERR: fail_invalid_constant_eval.carbon:[[@LINE+4]]:19: error: array bound is not a constant [InvalidArrayExpr]
+// CHECK:STDERR: let a: array(i32, Cpp.f(5)) = (1, 2, 3);
+// CHECK:STDERR:                   ^~~~~~~~
+// CHECK:STDERR:
+let a: array(i32, Cpp.f(5)) = (1, 2, 3);
+
+// --- nonconstant_constexpr_call.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp;
+
+var a: i32 = 0;
+
+inline Cpp '''
+constexpr int f(const int &r) { return r; }
+''';
+
+// OK, runtime call.
+var b: i32 = Cpp.f(a);
+
+// --- fail_nonconstant_consteval_call.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp;
+
+var a: i32 = 0;
+
+// TODO: This is failing when building the thunk, not when calling it.
+inline Cpp '''
+// CHECK:STDERR: fail_nonconstant_consteval_call.carbon:[[@LINE+9]]:15: error: call to consteval function 'f' is not a constant expression [CppInteropParseError]
+// CHECK:STDERR:    19 | consteval int f(const int &r) { return r; }
+// CHECK:STDERR:       |               ^
+// CHECK:STDERR: fail_nonconstant_consteval_call.carbon:[[@LINE+6]]:15: note: function parameter 'r' with unknown value cannot be used in a constant expression [CppInteropParseNote]
+// CHECK:STDERR:    19 | consteval int f(const int &r) { return r; }
+// CHECK:STDERR:       |               ^
+// CHECK:STDERR: fail_nonconstant_consteval_call.carbon:[[@LINE+3]]:15: note: declared here [CppInteropParseNote]
+// CHECK:STDERR:    19 | consteval int f(const int &r) { return r; }
+// CHECK:STDERR:       |               ^
+consteval int f(const int &r) { return r; }
+''';
+
+// CHECK:STDERR: fail_nonconstant_consteval_call.carbon:[[@LINE+11]]:14: note: in thunk for C++ function used here [InCppThunk]
+// CHECK:STDERR: var b: i32 = Cpp.f(a);
+// CHECK:STDERR:              ^~~~~~~~
+// CHECK:STDERR:
+// CHECK:STDERR: fail_nonconstant_consteval_call.carbon:[[@LINE+7]]:14: error: non-constant call to compile-time-only function [NonConstantCallToCompTimeOnlyFunction]
+// CHECK:STDERR: var b: i32 = Cpp.f(a);
+// CHECK:STDERR:              ^~~~~~~~
+// CHECK:STDERR: fail_nonconstant_consteval_call.carbon:[[@LINE-10]]:15: note: compile-time-only function declared here [CompTimeOnlyFunctionHere]
+// CHECK:STDERR: consteval int f(const int &r) { return r; }
+// CHECK:STDERR:               ^
+// CHECK:STDERR:
+var b: i32 = Cpp.f(a);

toolchain/check/testdata/interop/cpp/function/import/decayed_param.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/decayed_param.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/decayed_param.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/decayed_param.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/decayed_param.carbon
 
 // --- params.h
 

toolchain/check/testdata/interop/cpp/function/import/default_arg.carbon

@@ -7,9 +7,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/default_arg.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/default_arg.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/default_arg.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/default_arg.carbon
 
 // --- functions.h
 

toolchain/check/testdata/interop/cpp/function/import/extern_c.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/extern_c.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/extern_c.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/extern_c.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/extern_c.carbon
 
 // --- extern_c_function.carbon
 

toolchain/check/testdata/interop/cpp/function/import/full_semir.carbon

@@ -7,9 +7,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/full_semir.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/full_semir.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/full_semir.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/full_semir.carbon
 
 // ============================================================================
 // Function with short parameter

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

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/function.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/function.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/function.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/function.carbon
 
 // ============================================================================
 // Global

toolchain/check/testdata/interop/cpp/function/import/in_template.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/in_template.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/in_template.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/in_template.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/in_template.carbon
 
 // --- class_template.h
 

toolchain/check/testdata/interop/cpp/function/import/inline.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/inline.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/inline.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/inline.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/inline.carbon
 
 // ============================================================================
 // With definition

toolchain/check/testdata/interop/cpp/function/import/multiple_too_few_args_calls.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/multiple_too_few_args_calls.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/multiple_too_few_args_calls.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/multiple_too_few_args_calls.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/multiple_too_few_args_calls.carbon
 
 // --- fail_call_too_few_args.carbon
 

toolchain/check/testdata/interop/cpp/function/import/overloads.carbon

@@ -7,9 +7,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/overloads.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/overloads.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/overloads.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/overloads.carbon
 
 // ============================================================================
 // Overloaded sets tests

toolchain/check/testdata/interop/cpp/function/import/param_unsupported.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/param_unsupported.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/param_unsupported.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/param_unsupported.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/param_unsupported.carbon
 
 // ============================================================================
 // Unsupported primitive type

toolchain/check/testdata/interop/cpp/function/import/pointer.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/pointer.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/pointer.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/pointer.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/pointer.carbon
 
 // ============================================================================
 // Non-nullable pointer as a parameter type

toolchain/check/testdata/interop/cpp/function/import/qualified_param.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/qualified_param.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/qualified_param.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/qualified_param.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/qualified_param.carbon
 
 // --- qualifiers.h
 

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

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/reference.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/reference.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/reference.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/reference.carbon
 
 // ============================================================================
 // Lvalue reference as a parameter type

toolchain/check/testdata/interop/cpp/function/import/return.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/return.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/return.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/return.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/return.carbon
 
 // ============================================================================
 // Multiple function with a return value

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

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/struct.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/struct.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/struct.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/struct.carbon
 
 // ============================================================================
 // Forward-declared struct as parameter type

toolchain/check/testdata/interop/cpp/function/import/template.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/template.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/template.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/template.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/template.carbon
 
 // --- deduced_or_explicit.carbon
 

toolchain/check/testdata/interop/cpp/function/import/thunk_ast.carbon

@@ -8,9 +8,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/thunk_ast.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/thunk_ast.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/thunk_ast.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/thunk_ast.carbon
 // CHECK:STDOUT: TranslationUnitDecl {{0x[a-f0-9]+}} <<invalid sloc>> <invalid sloc>
 // CHECK:STDOUT: |-NamespaceDecl {{0x[a-f0-9]+}} <<invalid sloc>> <invalid sloc> Carbon
 

toolchain/check/testdata/interop/cpp/function/import/thunk_cpp26.carbon

@@ -7,9 +7,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/thunk_cpp26.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/thunk_cpp26.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/thunk_cpp26.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/thunk_cpp26.carbon
 
 // --- thunk_required.h
 

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

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/union.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/union.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/union.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/union.carbon
 
 // ============================================================================
 // Forward-declared union as parameter type

toolchain/check/testdata/interop/cpp/function/import/variadic.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/variadic.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/variadic.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/variadic.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/variadic.carbon
 
 // --- variadic.h
 

toolchain/check/testdata/interop/cpp/function/import/void_pointer.carbon

@@ -6,9 +6,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/void_pointer.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/import/void_pointer.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/void_pointer.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/import/void_pointer.carbon
 
 // --- non_nullable_param.carbon