OK.
On Wed, Apr 4, 2018 at 3:48 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> Hi!
>
> The maybe_range_for_decl argument is documented on
> cp_parser_simple_declaration as:
> If MAYBE_RANGE_FOR_DECL is not NULL, the pointed tree will be set to the
> parsed declaration if it is an uninitialized single declarator not followed
> by a `;', or to error_mark_node otherwise. Either way, the trailing `;',
> if present, will not be consumed. */
> but we initialize *maybe_range_for_decl to NULL_TREE at the beginning, to
> detect if we saw more than one decl; in case of a structured binding, we
> only set it to non-NULL on success and thus violate what the comment says,
> and on testcase like below we return is_range_for from the callers because
> it is followed by colon, yet range_decl is NULL and we ICE trying to
> dereference it. This patch ensures it is error_mark_node instead, it can
> only happen in case of errors.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2018-04-04 Jakub Jelinek <ja...@redhat.com>
>
> PR c++/85194
> * parser.c (cp_parser_simple_declaration): For structured bindings,
> if *maybe_range_for_decl is NULL after parsing it, set it to
> error_mark_node.
>
> * g++.dg/cpp1z/decomp37.C: New test.
>
> --- gcc/cp/parser.c.jj 2018-04-03 18:05:26.000000000 +0200
> +++ gcc/cp/parser.c 2018-04-04 14:59:53.562859572 +0200
> @@ -12993,8 +12993,14 @@ cp_parser_simple_declaration (cp_parser*
> /* The next token should be either a `,' or a `;'. */
> cp_token *token = cp_lexer_peek_token (parser->lexer);
> /* If it's a `;', we are done. */
> - if (token->type == CPP_SEMICOLON || maybe_range_for_decl)
> + if (token->type == CPP_SEMICOLON)
> goto finish;
> + else if (maybe_range_for_decl)
> + {
> + if (*maybe_range_for_decl == NULL_TREE)
> + *maybe_range_for_decl = error_mark_node;
> + goto finish;
> + }
> /* Anything else is an error. */
> else
> {
> --- gcc/testsuite/g++.dg/cpp1z/decomp37.C.jj 2018-04-04 15:12:33.724191835
> +0200
> +++ gcc/testsuite/g++.dg/cpp1z/decomp37.C 2018-04-04 15:13:40.803227382
> +0200
> @@ -0,0 +1,14 @@
> +// PR c++/85194
> +// { dg-do compile { target c++11 } }
> +// { dg-options "" }
> +
> +struct A { int i; };
> +
> +A x[2];
> +
> +void
> +foo ()
> +{
> + for (auto [i] = A () : x) // { dg-error "initializer in range-based
> 'for' loop" }
> + ; // { dg-warning "structured bindings only
> available with" "" { target c++14_down } .-1 }
> +}
>
> Jakub
