[Bug c++/99214] New: Incorrect template arguments shown in constraint satisfaction failure diagnostic

[Bug c++/99214] New: Incorrect template arguments shown in constraint satisfaction failure diagnostic

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99214

            Bug ID: 99214
           Summary: Incorrect template arguments shown in constraint
                    satisfaction failure diagnostic
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ppalka at gcc dot gnu.org
  Target Milestone: ---

$ cat testcase.C
template <class T>
struct A {
  template <class U> static void f() requires ([] { return U::fail; }());
  template <class U> static void f();
};

int main() {
  A<int>::f<char>();
}

$ cat testcase.C | g++-11 -std=c++20 -x c++ -
<stdin>: In substitution of ‘template<class U> static void A<int>::f<U>()
requires (<lambda>)() [with U = int]’:
<stdin>:8:19:   required from here
<stdin>:3:63: error: ‘fail’ is not a member of ‘char’

In the above diagnostic, the "in substitution of" context line incorrectly
shows "U = int" instead of "U = char".

GCC 10 shows the correct template arguments:

$ cat testcase.C | g++-10 -std=c++20 -x c++ -
<stdin>: In instantiation of ‘static void A<T>::f() requires (<lambda>)() [with
U = char; T = int]’:
<stdin>:8:19:   required from here
<stdin>:3:63: error: ‘fail’ is not a member of ‘char’

[Bug c++/99214] Incorrect template arguments shown in constraint satisfaction failure diagnostic

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99214

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Changed with r11-2774.

[Bug c++/99214] Incorrect template arguments shown in constraint satisfaction failure diagnostic

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99214

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-08-12

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.

[Bug c++/99214] Incorrect template arguments shown in constraint satisfaction failure diagnostic

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99214

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot gnu.org
             Status|NEW                         |ASSIGNED