[Bug c++/115897] [14/15 Regression] vector_size attribute on alias template has no effect when used in a dependent variable template-id

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115897

--- Comment #11 from GCC 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:9bcad238837e2100978cd839c343c488f72e1d4a

commit r15-2330-g9bcad238837e2100978cd839c343c488f72e1d4a
Author: Patrick Palka <ppalka@redhat.com>
Date:   Thu Jul 25 19:00:23 2024 -0400

    c++: alias of alias tmpl with dependent attrs [PR115897]

    As a follow-up to r15-2047-g7954bb4fcb6fa8, we also need to consider
    dependent attributes when recursing into a non-template alias that names
    a dependent alias template specialization (and so STF_STRIP_DEPENDENT
    is set), otherwise in the first testcase below we undesirably strip B
    all the way to T instead of to A<T>.

    We also need to move the typedef recursion case of strip_typedefs up to
    get checked before the compound type recursion cases.  Otherwise for C
    below (which ultimately aliases T*) we end up stripping it to T* instead
    of to A<T*> because the POINTER_TYPE recursion dominates the typedef
    recursion.  It also means we issue an unexpected extra error in the
    third testcase below.

    Ideally we would also want to consider dependent attributes on
    non-template aliases, so that we accept the second testcase below, but
    making that work correctly would require broader changes to e.g.
    structural_comptypes.

            PR c++/115897

    gcc/cp/ChangeLog:

            * tree.cc (strip_typedefs): Move up the typedef recursion case.
            Never strip a dependent alias template-id that has dependent
            attributes.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/alias-decl-78.C: New test.
            * g++.dg/cpp0x/alias-decl-79.C: New test.
            * g++.dg/cpp0x/alias-decl-pr92206-1a.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>