[Bug c++/110164] Improve diagnostic for incomplete standard library types due to missing include

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110164

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by David Malcolm <dmalc...@gcc.gnu.org>:

https://gcc.gnu.org/g:13709b518aa9769ef427e48ce5c9583fbe098777

commit r14-2055-g13709b518aa9769ef427e48ce5c9583fbe098777
Author: David Malcolm <dmalc...@redhat.com>
Date:   Fri Jun 23 17:56:14 2023 -0400

    c++: provide #include hint for missing includes [PR110164]

    PR c++/110164 notes that in cases where we have a forward decl
    of a std library type such as:

    std::array<int, 10> x;

    we emit this diagnostic:

    error: aggregate âstd::array<int, 10> xâ has incomplete type and cannot
be defined

    This patch adds this hint to the diagnostic:

    note: âstd::arrayâ is defined in header â<array>â; this is probably
fixable by adding â#include <array>â

    gcc/cp/ChangeLog:
            PR c++/110164
            * cp-name-hint.h (maybe_suggest_missing_header): New decl.
            * decl.cc: Define INCLUDE_MEMORY.  Add include of
            "cp/cp-name-hint.h".
            (start_decl_1): Call maybe_suggest_missing_header.
            * name-lookup.cc (maybe_suggest_missing_header): Remove "static".

    gcc/testsuite/ChangeLog:
            PR c++/110164
            * g++.dg/diagnostic/missing-header-pr110164.C: New test.

    Signed-off-by: David Malcolm <dmalc...@redhat.com>