[Bug c++/95303] New: Member type of class template is incorrectly printed in diagnostics when it fails to satisfy a concept

[Bug c++/95303] New: Member type of class template is incorrectly printed in diagnostics when it fails to satisfy a concept

[ensadc at mailnesia dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95303

            Bug ID: 95303
           Summary: Member type of class template is incorrectly printed
                    in diagnostics when it fails to satisfy a concept
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ensadc at mailnesia dot com
                CC: asutton at gcc dot gnu.org
  Target Milestone: ---

https://godbolt.org/z/F5Hj38

====
template<class>
struct A {
    struct B {};
};

template<class T>
concept C = requires (T&& t) {
    t.a;
};

static_assert(C<A<int>::B>);
====
<source>:11:15: error: static assertion failed
   11 | static_assert(C<A<int>::B>);
      |               ^~~~~~~~~~~~
<source>:11:15: note: constraints not satisfied
<source>:7:9:   required by the constraints of 'template<class T> concept C'
<source>:7:13:   in requirements with 'T&& t' [with T = A<int>::B<int>]
<source>:8:7: note: the required expression 't.a' is invalid
    8 |     t.a;
      |     ~~^
cc1plus: note: set '-fconcepts-diagnostics-depth=' to at least 2 for more
detail
====
Note '[with T = A<int>::B<int>]'. It should be '[with T = A<int>::B]', without
the second `<int>`.

[Bug c++/95303] [concepts] Member type of class template is incorrectly printed in diagnostics when it fails to satisfy a concept

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95303

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |10.0, 11.0
   Last reconfirmed|                            |2020-05-28
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
                 CC|                            |ppalka at gcc dot gnu.org

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Confirmed.

[Bug c++/95303] [concepts] Member type of class template is incorrectly printed in diagnostics when it fails to satisfy a concept

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95303

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

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

[Bug c++/95303] [concepts] Member type of class template is incorrectly printed in diagnostics when it fails to satisfy a concept

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95303

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:9845b7b45621e3833aee47276cb111e43be0e48b

commit r11-1903-g9845b7b45621e3833aee47276cb111e43be0e48b
Author: Patrick Palka <ppalka@redhat.com>
Date:   Tue Jul 7 16:33:12 2020 -0400

    c++: wrong pretty printing of nested type [PR95303]

    In the testcase below, we pretty print the nested type A<int>::B as
    A<int>::B<int> because we don't check whether B is itself a class
    template before printing the innermost set of template arguments from
    B's TEMPLATE_INFO (which in this case belong to A).  This patch fixes
    this by checking PRIMARY_TEMPLATE_P beforehand.

    gcc/cp/ChangeLog:

            PR c++/95303
            * cxx-pretty-print.c (pp_cxx_unqualified_id): Check
            PRIMARY_TEMPLATE_P before printing the innermost template
            arguments.

    gcc/testsuite/ChangeLog:

            PR c++/95303
            * g++.dg/concepts/diagnostic14.C: New test.

[Bug c++/95303] [concepts] Member type of class template is incorrectly printed in diagnostics when it fails to satisfy a concept

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95303

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.0
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 11.