(Another) ping.
On Sun, Apr 30, 2023 at 12:00:05PM +1000, Nathaniel Shead wrote:
> This patch ensures that any errors raised by finish_id_expression when
> parsing a decltype expression are properly reported, rather than
> potentially going ignored and causing invalid code to be accepted.
>
> We can also now remove the separate check for templates without args as
> this is also checked for in finish_id_expression.
>
> PR 100482
>
> gcc/cp/ChangeLog:
>
> * parser.cc (cp_parser_decltype_expr): Report errors raised by
> finish_id_expression.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/pr100482.C: New test.
>
> Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
> ---
> gcc/cp/parser.cc | 22 +++++++++++-----------
> gcc/testsuite/g++.dg/pr100482.C | 11 +++++++++++
> 2 files changed, 22 insertions(+), 11 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/pr100482.C
>
> diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
> index e5f032f2330..20ebcdc3cfd 100644
> --- a/gcc/cp/parser.cc
> +++ b/gcc/cp/parser.cc
> @@ -16508,10 +16508,6 @@ cp_parser_decltype_expr (cp_parser *parser,
> expr = cp_parser_lookup_name_simple (parser, expr,
> id_expr_start_token->location);
>
> - if (expr && TREE_CODE (expr) == TEMPLATE_DECL)
> - /* A template without args is not a complete id-expression. */
> - expr = error_mark_node;
> -
> if (expr
> && expr != error_mark_node
> && TREE_CODE (expr) != TYPE_DECL
> @@ -16532,13 +16528,17 @@ cp_parser_decltype_expr (cp_parser *parser,
> &error_msg,
> id_expr_start_token->location));
>
> - if (expr == error_mark_node)
> - /* We found an id-expression, but it was something that we
> - should not have found. This is an error, not something
> - we can recover from, so note that we found an
> - id-expression and we'll recover as gracefully as
> - possible. */
> - id_expression_or_member_access_p = true;
> + if (error_msg)
> + {
> + /* We found an id-expression, but it was something that we
> + should not have found. This is an error, not something
> + we can recover from, so report the error we found and
> + we'll recover as gracefully as possible. */
> + cp_parser_parse_definitely (parser);
> + cp_parser_error (parser, error_msg);
> + id_expression_or_member_access_p = true;
> + return error_mark_node;
> + }
> }
>
> if (expr
> diff --git a/gcc/testsuite/g++.dg/pr100482.C b/gcc/testsuite/g++.dg/pr100482.C
> new file mode 100644
> index 00000000000..dcf6722fda5
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/pr100482.C
> @@ -0,0 +1,11 @@
> +// { dg-do compile { target c++11 } }
> +
> +namespace N {}
> +decltype(std) x; // { dg-error "expected primary-expression" }
> +
> +struct S {};
> +decltype(S) y; // { dg-error "argument to .decltype. must be an expression"
> }
> +
> +template <typename T>
> +struct U {};
> +decltype(U) z; // { dg-error "missing template arguments" }
> --
> 2.40.0
>
