From 20cda2e85c307096a3856f7f27215b8a28982fb6 Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Thu, 13 Jun 2024 10:16:10 -0400 Subject: c++: undeclared identifier in requires-clause [PR99678] Since the terms of a requires-clause are grammatically primary-expressions and not e.g. postfix-expressions, it seems we need to explicitly handle and diagnose the case where a term parses to a bare unresolved identifier, like cp_parser_postfix_expression does, since cp_parser_primary_expression leaves that up to its callers. Otherwise we incorrectly accept the first three requires-clauses below. Note that the only occurrences of primary-expression in the grammar are postfix-expression and constraint-logical-and-expression, so it's not too surprising that we need this special handling here. PR c++/99678 gcc/cp/ChangeLog: * parser.cc (cp_parser_constraint_primary_expression): Diagnose a bare unresolved unqualified-id. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/concepts-requires38.C: New test. Reviewed-by: Jason Merrill (cherry picked from commit d387ecb2b2f44f33fd6a7c5ec7eadaf6dd70efc9) --- gcc/cp/parser.cc | 2 ++ gcc/testsuite/g++.dg/cpp2a/concepts-requires38.C | 14 ++++++++++++++ 2 files changed, 16 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-requires38.C diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index 598380d..6b786ed 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -31225,6 +31225,8 @@ cp_parser_constraint_primary_expression (cp_parser *parser, bool lambda_p) } if (pce == pce_ok) { + if (idk == CP_ID_KIND_UNQUALIFIED && identifier_p (expr)) + expr = unqualified_name_lookup_error (expr); cp_lexer_commit_tokens (parser->lexer); return finish_constraint_primary_expr (expr); } diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-requires38.C b/gcc/testsuite/g++.dg/cpp2a/concepts-requires38.C new file mode 100644 index 0000000..663195b --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-requires38.C @@ -0,0 +1,14 @@ +// PR c++/99678 +// { dg-do compile { target c++20 } } + +template +void f1() requires undeclared_identifier; // { dg-error "not declared" } + +template +void f2() requires true && undeclared_identifier; // { dg-error "not declared" } + +template +void f3() requires false || undeclared_identifier; // { dg-error "not declared" } + +template +void f4() requires undeclared_identifier(T{}); // { dg-error "must be enclosed in parentheses" } -- cgit v1.1