https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116239
--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:d44cae2d9310660e3e47f15202e86e4f73f15b37 commit r15-3489-gd44cae2d9310660e3e47f15202e86e4f73f15b37 Author: Marek Polacek <pola...@redhat.com> Date: Fri Aug 30 14:12:22 2024 -0400 c++: fn redecl in fn scope wrongly accepted [PR116239] Redeclaration such as void f(void); consteval void f(void); is invalid. In a namespace scope, we detect the collision in validate_constexpr_redeclaration, but not when one declaration is at block scope. When we have void f(void); void g() { consteval void f(void); } we call pushdecl on the second f and call push_local_extern_decl_alias. It finds the namespace-scope f: for (ovl_iterator iter (binding); iter; ++iter) if (decls_match (decl, *iter, /*record_versions*/false)) { alias = *iter; break; } but decls_match says they match so we just set DECL_LOCAL_DECL_ALIAS (and do not call another pushdecl leading to duplicate_decls which would detect mismatching return types, for example). I don't think we want to change decls_match, so a simple fix is to detect the problem in push_local_extern_decl_alias. PR c++/116239 gcc/cp/ChangeLog: * cp-tree.h (validate_constexpr_redeclaration): Declare. * decl.cc (validate_constexpr_redeclaration): No longer static. * name-lookup.cc (push_local_extern_decl_alias): Call validate_constexpr_redeclaration. gcc/testsuite/ChangeLog: * g++.dg/diagnostic/redeclaration-6.C: New test.
