https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80559
--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> --- commit c2ab9194438e2805bdc12916ebf40890267d62f5 Author: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4> Date: Tue Oct 4 20:42:58 2016 +0000 Implement P0091R2, Template argument deduction for class templates. * parser.c (cp_parser_simple_type_specifier): Parse class placeholder. Use the location of the beginning of the type-specifier. (cp_parser_init_declarator): Parse deduction guide. (cp_parser_diagnose_invalid_type_name): Mention class deduction. (cp_parser_type_id_1): Don't accept class placeholder as template arg. * cp-tree.h (CLASS_PLACEHOLDER_TEMPLATE): New. * decl.c (grokdeclarator): Check for uninitialized auto here. (start_decl_1): Not here. (cp_finish_decl): Or here. Don't collapse a list when doing class deduction. (grokfndecl): Check deduction guide scope and body. * error.c (dump_decl, dump_function_decl, dump_function_name): Handle deduction guides. * pt.c (make_template_placeholder, do_class_deduction): New. (build_deduction_guide, rewrite_template_parm): New. (dguide_name, dguide_name_p, deduction_guide_p): New. (do_auto_deduction): Call do_class_deduction. (splice_late_return_type, is_auto): Handle class placeholders. (template_parms_level_to_args): Split from template_parms_to_args. (tsubst_template_parms_level): Split from tsubst_template_parms. * typeck2.c (build_functional_cast): Handle class placeholder. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@240756 138bc75d-0d04-0410-961f-82ee72b054a4