[Bug c++/102039] New: another case of template function signature incorrectly dropping top-level cv-qualifier with function parameter dependent on template argument

[Bug c++/102039] New: another case of template function signature incorrectly dropping top-level cv-qualifier with function parameter dependent on template argument

[nickhuang99 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102039

            Bug ID: 102039
           Summary: another case of template function signature
                    incorrectly dropping top-level cv-qualifier with
                    function parameter dependent on template argument
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nickhuang99 at hotmail dot com
  Target Milestone: ---

You can say this is another dup of PR101402, but the nature is different
because the dependent-type is now from function template argument itself which
is different from another template class of PR101402. And that is why I file it
to be a possibly future test case.

struct A{
        typedef int Arr3[3];
};

template<class T>
void f(const typename T::Arr3){}

template<>
void f<A>(const int[3]){}

[Bug c++/102039] another case of template function signature incorrectly dropping top-level cv-qualifier with function parameter dependent on template argument

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102039

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |24666

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This is another one where the arrays decay too fast to pointers in the
argument.

Or rather not fast enough:
struct A{
        typedef int Arr3[3];
};
template<class T>
void f(const typename T::Arr3){}
template<>
void f<A>(const int*){}

Or maybe not, I will leave this more to C++ standards expert because ICC (EDG)
also rejects both of these testcases for the same reason as GCC.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24666
[Bug 24666] [meta-bug] array decaying to pointers

[Bug c++/102039] another case of template function signature incorrectly dropping top-level cv-qualifier with function parameter dependent on template argument

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102039

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

https://gcc.gnu.org/g:79802c5dcc043a515f429bb2bec7573b8537c32a

commit r12-4453-g79802c5dcc043a515f429bb2bec7573b8537c32a
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Sep 28 10:02:04 2021 -0400

    c++: array cv-quals and template specialization [PR101402]

    PRs 101402, 102033, etc. demonstrated that the fix for PR92010 wasn't
    handling all cases of the CWG1001/1322 issue with parameter type qual
    stripping and arrays with templates.  The problem turned out to be in
    determine_specialization, which did an extra substitution without the 92010
    fix and then complained that the result didn't match.

    But just removing that wrong/redundant code meant that we were accepting
    specializations with different numbers of parameters, because the code in
    fn_type_unification that compares types in this case wasn't checking for
    length mismatch.

    After fixing that, I realized that fn_type_unification couldn't tell the
    difference between variadic and non-variadic function types, because the
    args array doesn't include the terminal void we use to indicate
non-variadic
    function type.  So I added it, and made the necessary adjustments.

    Thanks to qingzhe "nick" huang <nickhuang99@hotmail.com> for the patch that
    led me to dig more into this, and the extensive testcases.

            PR c++/51851
            PR c++/101402
            PR c++/102033
            PR c++/102034
            PR c++/102039
            PR c++/102044

    gcc/cp/ChangeLog:

            * pt.c (determine_specialization): Remove redundant code.
            (fn_type_unification): Check for mismatched length.
            (type_unification_real): Ignore terminal void.
            (get_bindings): Don't stop at void_list_node.
            * class.c (resolve_address_of_overloaded_function): Likewise.

    gcc/testsuite/ChangeLog:

            * g++.dg/template/fnspec2.C: New test.
            * g++.dg/template/parm-cv1.C: New test.
            * g++.dg/template/parm-cv2.C: New test.
            * g++.dg/template/parm-cv3.C: New test.

[Bug c++/102039] another case of template function signature incorrectly dropping top-level cv-qualifier with function parameter dependent on template argument

[nickhuang99 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102039

qingzhe huang <nickhuang99 at hotmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #3 from qingzhe huang <nickhuang99 at hotmail dot com> ---
fixed by patch under PR101402