Here we were swallowing all the syntax errors by parsing tentatively, and returning error_mark_node without ever actually giving an error. Fixed by using save_tokens/rollback_tokens instead.
Tested x86_64-pc-linux-gnu, applying to trunk. PR c++/92517 * parser.c (cp_parser_constraint_primary_expression): Do the main parse non-tentatively. --- gcc/cp/parser.c | 17 +++++++---------- gcc/testsuite/g++.dg/cpp2a/concepts-syntax1.C | 9 +++++++++ 2 files changed, 16 insertions(+), 10 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-syntax1.C diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index e0f72302e5e..d4c9523289f 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -27478,7 +27478,7 @@ cp_parser_constraint_primary_expression (cp_parser *parser, bool lambda_p) return e; } - cp_parser_parse_tentatively (parser); + cp_lexer_save_tokens (parser->lexer); cp_id_kind idk; location_t loc = input_location; cp_expr expr = cp_parser_primary_expression (parser, @@ -27494,19 +27494,16 @@ cp_parser_constraint_primary_expression (cp_parser *parser, bool lambda_p) /* The primary-expression could be part of an unenclosed non-logical compound expression. */ pce = cp_parser_constraint_requires_parens (parser, lambda_p); - if (pce != pce_ok) - cp_parser_simulate_error (parser); - else - expr = finish_constraint_primary_expr (expr); } - if (cp_parser_parse_definitely (parser)) - return expr; - if (expr == error_mark_node) - return error_mark_node; + if (pce == pce_ok) + { + cp_lexer_commit_tokens (parser->lexer); + return finish_constraint_primary_expr (expr); + } /* Retry the parse at a lower precedence. If that succeeds, diagnose the error, but return the expression as if it were valid. */ - gcc_assert (pce != pce_ok); + cp_lexer_rollback_tokens (parser->lexer); cp_parser_parse_tentatively (parser); if (pce == pce_maybe_operator) expr = cp_parser_assignment_expression (parser, NULL, false, false); diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-syntax1.C b/gcc/testsuite/g++.dg/cpp2a/concepts-syntax1.C new file mode 100644 index 00000000000..0a47682c456 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-syntax1.C @@ -0,0 +1,9 @@ +// PR c++/92517 +// { dg-do compile { target concepts } } + +template <typename T> +concept C = true; + +template<int I> +requires C decltype<I> // { dg-error "" } +void f() {} base-commit: 3c7a03bc360c3511fae3747a71e579e9fd0824f9 -- 2.18.1