[Bug c++/103186] [11/12 Regression] ICE with lambda as default argument in template

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103186

--- Comment #13 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:8a3789786205376e3ba19fdefadd8937e8ac534e

commit r12-6973-g8a3789786205376e3ba19fdefadd8937e8ac534e
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Jan 26 16:42:57 2022 -0500

    c++: lambda in template default argument [PR103186]

    The problem with this testcase was that since my patch for PR97900 we
    weren't preserving DECL_UID identity for parameters of instantiations of
    templated functions, so using those parameters as the keys for the
    defarg_inst map broke.  I think this was always fragile given the
    possibility of redeclarations, so instead of reverting that change let's
    switch to keying off the function.

    Memory use compiling stdc++.h is not noticeably different.

            PR c++/103186

    gcc/cp/ChangeLog:

            * pt.cc (defarg_inst): Use tree_vec_map_cache_hasher.
            (defarg_insts_for): New.
            (tsubst_default_argument): Adjust.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/lambda/lambda-defarg10.C: New test.