On Wed, Jan 26, 2022 at 06:16:34PM -0500, Jason Merrill via Gcc-patches wrote:
> 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.
>
> Tested x86_64-pc-linux-gnu. Is the tree.{h,cc} change, just moving the class
> definition from one to the other, OK for trunk?
Ok.
> PR c++/103186
>
> gcc/ChangeLog:
>
> * tree.h (struct tree_vec_map_cache_hasher): Move from...
> * tree.cc (struct tree_vec_map_cache_hasher): ...here.
>
> gcc/cp/ChangeLog:
>
> * pt.cc (defarg_inst): Use tree_vec_map_cache_hasher.
> (defarg_inst_for): New.
> (tsubst_default_argument): Adjust.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/lambda/lambda-defarg10.C: New test.
Jakub
