Friendly ping. Thanks!
On 17 Sep 2024, at 14:14, Simon Martin wrote:
> The invalid test case in this PR highlights a bad interaction between
> the tentative_firewall and error recovery in cp_parser_decltype: the
> firewall makes cp_parser_skip_to_closing_parenthesis a no-op, and the
> parser does not make any progress, running "forever".
>
> This patch calls cp_parser_commit_to_tentative_parse before initiating
> error recovery.
>
> Successfully tested on x86_64-pc-linux-gnu.
>
> PR c++/114858
>
> gcc/cp/ChangeLog:
>
> * parser.cc (cp_parser_decltype): Commit tentative parse before
> initiating error recovery.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/decltype10.C: Adjust test expectation.
> * g++.dg/cpp2a/pr114858.C: New test.
> ---
> gcc/cp/parser.cc | 3 +++
> gcc/testsuite/g++.dg/cpp0x/decltype10.C | 2 ++
> gcc/testsuite/g++.dg/cpp2a/pr114858.C | 25
> +++++++++++++++++++++++++
> 3 files changed, 30 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/pr114858.C
>
> diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
> index 4dd9474cf60..3a7c5ffe4c8 100644
> --- a/gcc/cp/parser.cc
> +++ b/gcc/cp/parser.cc
> @@ -17508,6 +17508,9 @@ cp_parser_decltype (cp_parser *parser)
> /* Parse to the closing `)'. */
> if (expr == error_mark_node || !parens.require_close (parser))
> {
> + /* Commit to the tentative_firewall so we actually skip to the
> closing
> + parenthesis. */
> + cp_parser_commit_to_tentative_parse (parser);
> cp_parser_skip_to_closing_parenthesis (parser, true, false,
> /*consume_paren=*/true);
> expr = error_mark_node;
> diff --git a/gcc/testsuite/g++.dg/cpp0x/decltype10.C
> b/gcc/testsuite/g++.dg/cpp0x/decltype10.C
> index fe7247269f5..bd606e325d4 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/decltype10.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/decltype10.C
> @@ -7,3 +7,5 @@ template<int> struct A
> };
>
> template<int N> int A<N>::i(decltype (A::i; // { dg-error "expected"
> }
> +
> +// { dg-excess-errors "" }
> diff --git a/gcc/testsuite/g++.dg/cpp2a/pr114858.C
> b/gcc/testsuite/g++.dg/cpp2a/pr114858.C
> new file mode 100644
> index 00000000000..6ffde4c3a2c
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/pr114858.C
> @@ -0,0 +1,25 @@
> +// PR c++/114858
> +// { dg-do compile { target c++20 } }
> +// { dg-timeout 2 }
> +
> +template <class F> void g(F);
> +template <class... A>
> +auto h(A &&... a) -> decltype(
> + decltype(g< // { dg-error "expected primary-expression" }
> + decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<
> + decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<
> + decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<
> + decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<
> + decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<
> + decltype(g<decltype(g<
> + decltype()>)(a)...)
> +{
> + h([] {});
> +}
> +
> +int main() {
> + h();
> + return 0;
> +}
> +
> +// { dg-excess-errors "" }
> --
> 2.44.0
