Re: [PATCH] c++: suppress all warnings on memper pointers to work around dICE [PR101219]

[Jeff Law <jeffreyalaw@gmail.com>]

On 7/22/2021 5:15 PM, Sergei Trofimovich via Gcc-patches wrote:
> From: Sergei Trofimovich <siarheit@google.com>
>
> r12-1804 ("cp: add support for per-location warning groups.") among other
> things removed warning suppression from a few places including ptrmemfuncs.
>
> Currently ptrmemfuncs don't have valid BINFO attached which causes ICEs
> in access checks:
>
>      crash_signal
>          gcc/toplev.c:328
>      perform_or_defer_access_check(tree_node*, tree_node*, tree_node*, int, access_failure_info*)
>          gcc/cp/semantics.c:490
>      finish_non_static_data_member(tree_node*, tree_node*, tree_node*)
>          gcc/cp/semantics.c:2208
>      ...
>
> The change suppresses warnings again until we provide BINFOs for ptrmemfuncs.
>
> 	PR c++/101219
>
> gcc/cp/ChangeLog:
>
> 	* typeck.c (build_ptrmemfunc_access_expr): Suppress all warnings
> 	to avoid ICE.
>
> gcc/testsuite/ChangeLog:
>
> 	* g++.dg/torture/pr101219.C: New test.
The C++ maintainers have the final say here, but ISTM that warning 
suppression shouldn't be used to avoid an ICE, even an ICE within the 
warning or diagnostic code itself.

jeff