On 2/16/24 04:21, Jakub Jelinek wrote:
Hi!For template parameters, the optional this specifier is in the grammar template-parameter-list -> template-parameter -> parameter-declaration, just [dcl.fct/6] says that it is only valid in parameter-list of certain functions. So, unlike the case of decl-specifier-seq used in non-terminals other than parameter-declaration, I think it is better not to fix this by cp_parser_decl_specifier_seq (parser, - flags | CP_PARSER_FLAGS_PARAMETER, + flags | (template_parameter_p ? 0 + : CP_PARSER_FLAGS_PARAMETER), &decl_specifiers, &declares_class_or_enum); which would be pretending it isn't in the grammar, but by diagnosing it separately, which is what the following patch does. Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
2024-02-16 Jakub Jelinek <ja...@redhat.com> PR c++/113929 * parser.cc (cp_parser_parameter_declaration): Diagnose this specifier on template parameter declaration. * g++.dg/parse/pr113929.C: New test. --- gcc/cp/parser.cc.jj 2024-02-15 17:33:11.641453437 +0100 +++ gcc/cp/parser.cc 2024-02-15 17:40:29.592447265 +0100 @@ -25724,8 +25724,15 @@ cp_parser_parameter_declaration (cp_pars for a C-style variadic function. */ token = cp_lexer_peek_token (parser->lexer);- bool const xobj_param_p+ bool xobj_param_p = decl_spec_seq_has_spec_p (&decl_specifiers, ds_this); + if (xobj_param_p && template_parm_p) + { + error_at (decl_specifiers.locations[ds_this], + "%<this%> specifier in template parameter declaration"); + xobj_param_p = false; + decl_specifiers.locations[ds_this] = 0; + }bool diag_xobj_parameter_pack = false;if (xobj_param_p && (declarator && declarator->parameter_pack_p)) --- gcc/testsuite/g++.dg/parse/pr113929.C.jj 2024-02-15 17:43:18.500129688 +0100 +++ gcc/testsuite/g++.dg/parse/pr113929.C 2024-02-15 17:42:54.564458109 +0100 @@ -0,0 +1,7 @@ +// PR c++/113929 +// { dg-do compile } + +template <this int C> // { dg-error "'this' specifier in template parameter declaration" } +struct S {}; +template <int N, this int C> // { dg-error "'this' specifier in template parameter declaration" } +struct T {}; Jakub
