[libc++][test] Do not test Clang bug in is_constructible.pass.cpp

[cpplearner]

A comment in is_constructible.pass.cpp suggests that Clang is non-conforming in accepting construction of const int& from ExplicitTo<int&&>.

llvm-project/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp

Lines 225 to 229 in 3ef64f7

	// Binding through reference-compatible type is required to perform
	// direct-initialization as described in [over.match.ref] p. 1 b. 1:
	//
	// But the rvalue to lvalue reference binding isn't allowed according to
	// [over.match.ref] despite Clang accepting it.

This PR changes the test to expect the standard-conforming behavior, which makes the test pass on MSVC.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: S. B. Tam (cpplearner)

Changes

A comment in is_constructible.pass.cpp suggests that Clang is non-conforming in accepting construction of const int& from ExplicitTo<int&&>.

llvm-project/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp

Lines 225 to 229 in 3ef64f7

	// Binding through reference-compatible type is required to perform
	// direct-initialization as described in [over.match.ref] p. 1 b. 1:
	//
	// But the rvalue to lvalue reference binding isn't allowed according to
	// [over.match.ref] despite Clang accepting it.

This PR changes the test to expect the standard-conforming behavior, which makes the test pass on MSVC.

---

Full diff: https://github.com/llvm/llvm-project/pull/105964.diff

1 Files Affected:

• (modified) libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp (+2-2)

diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
index 578efb90f7f1ab..9f1bb50e76dc97 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
@@ -228,8 +228,8 @@ int main(int, char**)
     // But the rvalue to lvalue reference binding isn't allowed according to
     // [over.match.ref] despite Clang accepting it.
     test_is_constructible<int&, ExplicitTo<int&>>();
-#ifndef TEST_COMPILER_GCC
-    test_is_constructible<const int&, ExplicitTo<int&&>>();
+#ifndef __clang__
+    test_is_not_constructible<const int&, ExplicitTo<int&&>>();
 #endif
 
     static_assert(std::is_constructible<int&&, ExplicitTo<int&&>>::value, "");

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff 3ef64f7ab5b8651eab500cd944984379fce5f639 803712c89a3c25cec4890f6b1e4c3f776c414ade --extensions cpp -- libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp

View the diff from clang-format here.

diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
index 9a5efe7b5f..835a736f64 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
@@ -228,9 +228,9 @@ int main(int, char**)
     // But the rvalue to lvalue reference binding isn't allowed according to
     // [over.match.ref] despite Clang accepting it.
     test_is_constructible<int&, ExplicitTo<int&>>();
-#ifndef TEST_COMPILER_CLANG
+#  ifndef TEST_COMPILER_CLANG
     test_is_not_constructible<const int&, ExplicitTo<int&&>>();
-#endif
+#  endif
 
     static_assert(std::is_constructible<int&&, ExplicitTo<int&&>>::value, "");