https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92439
--- Comment #3 from asutton at gcc dot gnu.org --- Author: asutton Date: Wed Nov 27 15:16:37 2019 New Revision: 278774 URL: https://gcc.gnu.org/viewcvs?rev=278774&root=gcc&view=rev Log: 2019-11-27 Andrew Sutton <asut...@lock3software.com> PR c++/92439 Improve quality of diagnostics for subexpressions that need parens. gcc/cp/ * parser.c (cp_parser_requires_clause_opt): Add a flag to indicate when parsing a requires-clause before lambda parameters, and... (cp_parser_lambda_declarator_opt): ... use that here ... (cp_parser_type_parameter): ... and here ... (cp_parser_late_return_type_opt): ... and here ... (cp_parser_explicit_template_declaration): ... and here. (cp_parser_diagnose_ungrouped_constraint_plain): Adjust the message because this can apply to subexpressions that are not immediately after a requires-clause. (cp_parser_diagnose_ungrouped_constraint_rich): Likewise. (primary_constraint_error): New. (cp_parser_constraint_requires_parens): New. (cp_parser_unary_constraint_requires_parens): New. (cp_parser_constraint_primary_expression): Check for unary expressions before parsing the primary expression. Also check for binary and postfix operators after a successful parse of the primary expression. Force a re-parse if the result would form a lower-precedence string. (cp_parser_constraint_logical_and_expression): Propagate lambda flag; move checks for ill-formed constraints into the constraint primary expression. (cp_parser_constraint_logical_or_expression): Likewise. (cp_parser_requires_clause_expression): Propagate lambda flag. gcc/testsuite/ * g++.dg/cpp2a/concepts-requires20.C: New. Added: trunk/gcc/testsuite/g++.dg/cpp2a/concepts-requires20.C Modified: trunk/gcc/cp/ChangeLog trunk/gcc/cp/parser.c trunk/gcc/testsuite/ChangeLog
