On Sun, 30 Apr 2023, Nathaniel Shead via Gcc-patches 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.
LGTM. Some minor comments about the new testcase below:
>
> 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
We generally prefer to organize tests according to the language dialect
they apply to and the langugae construct that they're primarily testing.
In this case we could name the test e.g.
gcc/testsuite/g++.dg/cpp0x/decltype-100482.C
> @@ -0,0 +1,11 @@
> +// { dg-do compile { target c++10 } }
We also usually mention the PR number in the test as a comment:
// PR c++/100482
One benefit of doing so is that the git alias 'git gcc-commit-mklog'
(https://gcc.gnu.org/gitwrite.html#vendor) will then automatically
include the PR number in the commit message template.
> +
> +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
>
>
