https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116418
--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:12bdcc3d7970860b9d66ed4dea203bde8fd68d4d commit r15-3611-g12bdcc3d7970860b9d66ed4dea203bde8fd68d4d Author: Patrick Palka <ppa...@redhat.com> Date: Thu Sep 12 12:45:03 2024 -0400 c++: decltype(auto) deduction of statement-expression [PR116418] r8-7538 for PR84968 made strip_typedefs_expr diagnose STATEMENT_LIST so that we reject statement-expressions in noexcept-specifiers to match our behavior in template arguments (which the parser diagnoses directly). Later r11-7452 made decltype(auto) deduction canonicalize the expression (as an implementation detail) which in turn calls strip_typedefs_expr, and so ever since we inadvertently reject decltype(auto) deduction of a statement-expression. This patch just removes the diagnostic in strip_typedefs_expr and instead treats statement-expressions similar to lambda-expressions. The function doesn't seem like the right place for such a diagnostic and so it seems easier to just accept rather than try to reject them in a suitable place. PR c++/116418 gcc/cp/ChangeLog: * tree.cc (strip_typedefs_expr) <case STATEMENT_LIST>: Replace this error path with ... <case STMT_EXPR>: ... this, returning the original tree. gcc/testsuite/ChangeLog: * g++.dg/eh/pr84968.C: No longer expect an ahead of time diagnostic for the statement-expresssion. Instantiate the template and expect an incomplete type error instead. * g++.dg/ext/stmtexpr26.C: New test. Reviewed-by: Jason Merrill <ja...@redhat.com>
