Re: [PATCH] testsuite: Add yet another [[clang::no_specializations]] testcase [PR120635]

On 7/16/26 7:04 AM, Jakub Jelinek wrote:
> Hi!
> 
> In the libstdc++ _Clang::no_specializations thread, we've noticed that
> the GCC implementation can properly handle attributes on template
> declarations followed by primary template definitions without the attribute
> and still diagnose later explicit or partial specializations, while
> clang++ didn't handle that.  clang++ is being fixed, the following patch
> adds another testcase to verify we don't regress in that.
> 
> Tested on x86_64-linux, ok for trunk?

OK.
> 2026-07-16  Jakub Jelinek  <[email protected]>
> 
> 	PR c++/120635
> 	* g++.dg/ext/attr-no_specializations13.C: New test.
> 
> --- gcc/testsuite/g++.dg/ext/attr-no_specializations13.C.jj	2026-07-16 12:13:57.764783153 +0200
> +++ gcc/testsuite/g++.dg/ext/attr-no_specializations13.C	2026-07-16 12:50:44.296473787 +0200
> @@ -0,0 +1,25 @@
> +// PR c++/120635
> +// { dg-do compile { target c++11 } }
> +
> +template <typename T, typename U>
> +struct [[clang::no_specializations]] A;
> +template <typename T, typename U>
> +struct A {};
> +template <>
> +struct A <int, int> { int a; };			// { dg-error "'struct A<int, int>' cannot be specialized" }
> +#if __cpp_variable_templates >= 201304
> +template <typename T>
> +struct B {
> +  template <typename U>
> +  static int b [[clang::no_specializations]];
> +};
> +template <>
> +template <>
> +int B<int>::b <long> = 43;			// { dg-error "'B<int>::b<long int>' cannot be specialized" "" { target c++14 } }
> +#endif
> +template <typename T>
> +[[clang::no_specializations]] int foo ();
> +template <typename T>
> +int foo () { return 42; }
> +template <>
> +int foo <long> () { return 43; }		// { dg-error "'int foo\\\(\\\) \\\[with T = long int\\\]' cannot be specialized" }
> 
> 	Jakub
>