[Bug c++/114303] [11/12/13 Regression] ICE with constexpr if and accessing captures across nested generic lambdas

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114303

--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:47cac09307874ff1d640392e3d986453f34f7bcb

commit r13-8767-g47cac09307874ff1d640392e3d986453f34f7bcb
Author: Patrick Palka <ppalka@redhat.com>
Date:   Thu Apr 11 10:16:41 2024 -0400

    c++: build_extra_args recapturing local specs [PR114303]

    r13-6452-g341e6cd8d603a3 made build_extra_args walk evaluated contexts
    first so that we prefer processing a local specialization in an evaluated
    context even if its first use is in an unevaluated context.  But this
    means we need to avoid walking a tree that already has extra args/specs
    saved because the list of saved specs appears to be an evaluated
    context which we'll now walk first.  It seems then that we should be
    calculating the saved specs from scratch each time, rather than
    potentially walking the saved specs list from an earlier partial
    instantiation when calling build_extra_args a second time around.

            PR c++/114303

    gcc/cp/ChangeLog:

            * constraint.cc (tsubst_requires_expr): Clear
            REQUIRES_EXPR_EXTRA_ARGS before calling build_extra_args.
            * pt.cc (tree_extra_args): Define.
            (extract_locals_r): Assert *_EXTRA_ARGS is empty.
            (tsubst_stmt) <case IF_STMT>: Clear IF_SCOPE on the new
            IF_STMT.  Call build_extra_args on the new IF_STMT instead
            of t which might already have IF_STMT_EXTRA_ARGS.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp1z/constexpr-if-lambda6.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>
    (cherry picked from commit b262b17636e47ae969a74f16e86ccb00678d5e88)