tests for substitute

Signed-off-by: Valentyn Yukhymenko <[email protected]>

libcxx/test/std/experimental/reflection/substitute.verify.cpp

@@ -0,0 +1,37 @@
+//===----------------------------------------------------------------------===//
+//
+// Copyright 2024 Bloomberg Finance L.P.
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03 || c++11 || c++14 || c++17 || c++20
+// ADDITIONAL_COMPILE_FLAGS: -freflection -freflection-new-syntax
+// ADDITIONAL_COMPILE_FLAGS: -Wno-unused-variable -Wno-unused-value
+
+// <experimental/reflection>
+//
+// [reflection]
+
+#include <experimental/meta>
+#include <vector>
+
+int main() {
+  can_substitute(^^std::vector, {^^int}); //ok
+  substitute(^^std::vector, {^^int}); //ok
+
+  can_substitute(^^int, {^^int});
+  // expected-error-re@-1 {{call to consteval function 'std::meta::can_substitute<{{.*}}>' is not a constant expression}}
+  // expected-note-re@-2 {{expected a reflection of a template, but got {{.*}}}}
+
+  substitute(^^int, {^^int});
+  // expected-error-re@-1 {{call to consteval function 'std::meta::substitute<{{.*}}>' is not a constant expression}}
+  // expected-note-re@-2 {{expected a reflection of a template, but got {{.*}}}}
+
+  substitute(^^std::vector, {^^::});
+  // expected-error-re@-1 {{call to consteval function 'std::meta::substitute<{{.*}}>' is not a constant expression}}
+  // expected-note-re@-2 {{a reflection of {{.*}} cannot represent a template argument}}
+}