[Bug c++/96830] GCC does not complain template-head containing requires clause

["redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96830

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2020-08-28 00:00:00         |2022-7-20

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Another examples:

template<class T> requires true
struct S
{
  template<class U>
    friend struct S;
};

S<int> s;



EDG:

"diff.C", line 5: error: requires-clause incompatible with class template "S"
          (declared at line 2)
      friend struct S;
                    ^
          detected during instantiation of class "S<T> [with T=int]" at line 8

1 error detected in the compilation of "diff.C".


Clang:

diff.C:4:3: error: requires clause differs in template redeclaration
  template<class U>
  ^
diff.C:8:8: note: in instantiation of template class 'S<int>' requested here
S<int> s;
       ^
diff.C:1:28: note: previous template declaration is here
template<class T> requires true
                           ^
1 error generated.