From 2f90f3850eaf9d703d9eb63d5f0347158aa11027 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Fri, 16 Aug 2024 11:43:18 +0200 Subject: c++: Pedwarn on [[]]; at class scope [PR110345] For C++ 26 P2552R3 I went through all the spots (except modules) where attribute-specifier-seq appears in the grammar and tried to construct a testcase in all those spots, for now for [[deprecated]] attribute. The fourth issue is that we just emit (when enabled) -Wextra-semi warning not just for lone semicolon at class scope (correct), but also for [[]]; or [[whatever]]; there too. While just semicolon is valid in C++11 and newer, https://eel.is/c++draft/class.mem#nt:member-declaration allows empty-declaration, unlike namespace scope or block scope something like attribute-declaration or empty statement with attributes applied for it aren't supported. While syntactically it matches attribute-specifier-seq [opt] decl-specifier-seq [opt] member-declarator-list [opt] ; with the latter two omitted, there is https://eel.is/c++draft/class.mem#general-3 which says that is not valid. So, the following patch emits a pedwarn in that case. 2024-08-16 Jakub Jelinek PR c++/110345 * parser.cc (cp_parser_member_declaration): Call maybe_warn_extra_semi only if it is empty-declaration, if there are some tokens like attribute, pedwarn that the declaration doesn't declare anything. * g++.dg/cpp0x/gen-attrs-84.C: New test. --- gcc/cp/parser.cc | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'gcc/cp/parser.cc') diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index 852efe4..c9654cf 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -28259,7 +28259,11 @@ cp_parser_member_declaration (cp_parser* parser) if (!decl_specifiers.any_specifiers_p) { cp_token *token = cp_lexer_peek_token (parser->lexer); - maybe_warn_extra_semi (token->location, extra_semi_kind::member); + if (decl_spec_token_start == token) + maybe_warn_extra_semi (token->location, extra_semi_kind::member); + else + pedwarn (decl_spec_token_start->location, OPT_Wpedantic, + "declaration does not declare anything"); } else { -- cgit v1.1