[Bug c++/66968] Incorrect template argument shown in diagnostic

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66968

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:

https://gcc.gnu.org/g:3dbc7b809a62167b36f217ab5f43207be19e5908

commit r12-2379-g3dbc7b809a62167b36f217ab5f43207be19e5908
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Jul 16 20:59:43 2021 +0100

    libstdc++: Improve diagnostics for std::get with invalid tuple index

    This adds a deleted overload of std::get<I>(const tuple<Types...>&).
    Invalid calls with an out of range index will match the deleted overload
    and give a single, clear error about calling a deleted function, instead
    of overload resolution errors for every std::get overload in the
    library.

    This changes the current output of 15+ errors (plus notes and associated
    header context) into just two errors (plus context):

    error: static assertion failed: tuple index must be in range
    error: use of deleted function 'constexpr std::__enable_if_t<(__i >=
sizeof... (_Types))> std::get(const std::tuple<_Types ...>&) [with long
unsigned int __i = 1; _Elements = {int}; std::__enable_if_t<(__i >= sizeof...
(_Types))> = void]'

    This seems like a nice improvement, although PR c++/66968 means that
    "_Types" is printed in the signature rather than "_Elements".

    Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

    libstdc++-v3/ChangeLog:

            * include/std/tuple (get<I>): Add deleted overload for bad
            index.
            * testsuite/20_util/tuple/element_access/get_neg.cc: Adjust
            expected errors.