{"id":2225518,"url":"http://patchwork.ozlabs.org/api/patches/2225518/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/aecXWG8aqJfdhcDI@tucnak/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/projects/17/?format=json","name":"GNU Compiler Collection","link_name":"gcc","list_id":"gcc-patches.gcc.gnu.org","list_email":"gcc-patches@gcc.gnu.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"","list_archive_url":null,"date":"2026-04-21T06:21:12","name":"c++: Parse splice-type-specifier in cp_parser_mem_initializer_id [PR124944]","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"ad6dfd0a2db92e69197da42601cba48d5f88c016","submitter":{"id":671,"url":"http://patchwork.ozlabs.org/api/people/671/?format=json","name":"Jakub Jelinek","email":"jakub@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/aecXWG8aqJfdhcDI@tucnak/mbox/","series":[{"id":500740,"url":"http://patchwork.ozlabs.org/api/series/500740/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=500740","date":"2026-04-21T06:21:12","name":"c++: Parse splice-type-specifier in cp_parser_mem_initializer_id [PR124944]","version":1,"mbox":"http://patchwork.ozlabs.org/series/500740/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2225518/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2225518/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","gcc-patches@gcc.gnu.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","gcc-patches@gcc.gnu.org"],"Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=abErREeT;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=2620:52:6:3111::32; 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charset=us-ascii","Content-Disposition":"inline","X-BeenThere":"gcc-patches@gcc.gnu.org","X-Mailman-Version":"2.1.30","Precedence":"list","List-Id":"Gcc-patches mailing list ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Reply-To":"Jakub Jelinek ","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"},"content":"Hi!\n\nThe grammar has:\nmem-initializer-id:\n\tclass-or-decltype\n\tidentifier\nclass-or-decltype:\n\tnested-name-specifier[opt] type-name\n\tnested-name-specifier template simple-template-id\n\tcomputed-type-specifier\ncomputed-type-specifier:\n\tdecltype-specifier\n\tpack-index-specifier\n\tsplice-type-specifier\nbut we weren't parsing splice-type-specifier in there, just in\ncp_parser_base_specifier. So, the following patch defers\nsimilarly to cp_parser_base_specifier the typename diagnostics\nbecause we don't know whether typename [: will be valid or not\n- it could be splice-scope-specifier and in that case typename\nis not valid, or splice-type-specifier, in which case it is valid\nbut not required. And calls cp_parser_splice_type_specifier too\nwhen nested-name-specifier nor :: don't appear.\n\nBootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?\n\n2026-04-21 Jakub Jelinek \n\n\tPR c++/124944\n\t* parser.cc (cp_parser_mem_initializer_id): Parse\n\tsplice-type-specifier.\n\n\t* g++.dg/reflect/splice13.C: New test.\n\t* g++.dg/reflect/splice14.C: New test.\n\n\n\tJakub","diff":"--- gcc/cp/parser.cc.jj\t2026-04-16 18:56:51.665066851 +0200\n+++ gcc/cp/parser.cc\t2026-04-20 20:14:17.454246322 +0200\n@@ -19974,14 +19974,17 @@ cp_parser_mem_initializer_id (cp_parser*\n bool template_p = false;\n tree id;\n \n- cp_token *token = cp_lexer_peek_token (parser->lexer);\n+ cp_token *typename_token = nullptr, *splice_token = nullptr;\n \n- /* `typename' is not allowed in this context ([temp.res]). */\n+ /* `typename' is not allowed in this context ([temp.res]), unless\n+ it is part of splice-type-specifier. Defer diagnostics for now\n+ because it needs to be diagnosed if followed by splice-scope-specifier\n+ but not when followed by splice-type-specifier. */\n if (cp_lexer_next_token_is_keyword (parser->lexer, RID_TYPENAME))\n {\n- error_at (token->location,\n-\t\t\"keyword % not allowed in this context (a qualified \"\n-\t\t\"member initializer is implicitly a type)\");\n+ typename_token = cp_lexer_peek_token (parser->lexer);\n+ if (cp_parser_next_tokens_start_splice_type_spec_p (parser, true))\n+\tsplice_token = cp_lexer_peek_nth_token (parser->lexer, 2);\n cp_lexer_consume_token (parser->lexer);\n }\n /* Look for the optional `::' operator. */\n@@ -20008,6 +20011,12 @@ cp_parser_mem_initializer_id (cp_parser*\n \t\t\t\t\t /*type_p=*/true,\n \t\t\t\t\t /*is_declaration=*/true)\n != NULL_TREE);\n+ if (typename_token && cp_lexer_peek_token (parser->lexer) != splice_token)\n+ /* Emit deferred diagnostics for invalid typename keyword if\n+ cp_parser_nested_name_specifier_opt parsed splice-scope-specifier. */\n+ error_at (typename_token->location,\n+\t \"keyword % not allowed in this context (a qualified \"\n+\t \"member initializer is implicitly a type)\");\n if (nested_name_specifier_p)\n template_p = cp_parser_optional_template_keyword (parser);\n /* If there is a `::' operator or a nested-name-specifier, then we\n@@ -20020,6 +20029,14 @@ cp_parser_mem_initializer_id (cp_parser*\n \t\t\t\t /*check_dependency_p=*/true,\n \t\t\t\t /*class_head_p=*/false,\n \t\t\t\t /*is_declaration=*/true);\n+ else if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_SPLICE))\n+ {\n+ /* Parse C++26 splice-type-specifier. */\n+ id = cp_parser_splice_type_specifier (parser);\n+ if (id == NULL_TREE)\n+\treturn error_mark_node;\n+ return id;\n+ }\n /* Otherwise, we could also be looking for an ordinary identifier. */\n cp_parser_parse_tentatively (parser);\n if (cp_lexer_next_token_is_decltype (parser->lexer))\n--- gcc/testsuite/g++.dg/reflect/splice13.C.jj\t2026-04-20 20:17:23.199120525 +0200\n+++ gcc/testsuite/g++.dg/reflect/splice13.C\t2026-04-20 20:16:47.095728081 +0200\n@@ -0,0 +1,23 @@\n+// PR c++/124944\n+// { dg-do compile { target c++26 } }\n+// { dg-additional-options \"-freflection\" }\n+\n+struct A {};\n+constexpr auto x = ^^A;\n+\n+struct B : [: x :] {\n+ B () : typename [: x :] () {}\n+};\n+\n+struct C : [: x :] {\n+ C () : [: x :] () {}\n+};\n+\n+namespace D {\n+ struct E {};\n+}\n+constexpr auto y = ^^D;\n+\n+struct F : [: y :]::E {\n+ F () : [: y :]::E () {}\n+};\n--- gcc/testsuite/g++.dg/reflect/splice14.C.jj\t2026-04-20 20:17:30.732993744 +0200\n+++ gcc/testsuite/g++.dg/reflect/splice14.C\t2026-04-20 20:20:51.386617097 +0200\n@@ -0,0 +1,12 @@\n+// PR c++/124944\n+// { dg-do compile { target c++26 } }\n+// { dg-additional-options \"-freflection\" }\n+\n+namespace D {\n+ struct E {};\n+}\n+constexpr auto y = ^^D;\n+\n+struct F : [: y :]::E {\n+ F () : typename [: y :]::E () {}\t// { dg-error \"keyword 'typename' not allowed in this context \\\\\\(a qualified member initializer is implicitly a type\\\\\\)\" }\n+};\n","prefixes":[]}