Re: [PR c++/71965] silence multi-dim array init sorry without tf_error

[Jason Merrill <jason at redhat dot com>]

On Sat, Mar 17, 2018 at 8:11 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
> We shouldn't substitute templates into short-circuited-out concepts
> constraints, but we do, and to add insult to injury, we issue a
> sorry() error when a concept that shouldn't even have been substituted
> attempts to perform a multi-dimensional array initialization with a
> new{} expression.
>
> Although fixing the requirements short-circuiting is probably too
> risky at this point, we can get closer to the intended effect by
> silencing that sorry just as we silence other errors.
>
> for  gcc/cp/ChangeLog
>
>         PR c++/71965
>         * init.c (build_vec_init): Silence sorry without tf_error.
>
> for  gcc/testsuite/ChangeLog
>
>         PR c++/71965
>         * g++.dg/concepts/pr71965.C: New.
> ---
>  gcc/cp/init.c                           |   19 ++++++++++++-------
>  gcc/testsuite/g++.dg/concepts/pr71965.C |   27 +++++++++++++++++++++++++++
>  2 files changed, 39 insertions(+), 7 deletions(-)
>  create mode 100644 gcc/testsuite/g++.dg/concepts/pr71965.C
>
> diff --git a/gcc/cp/init.c b/gcc/cp/init.c
> index cb62f4886e6d..dcaad730dc86 100644
> --- a/gcc/cp/init.c
> +++ b/gcc/cp/init.c
> @@ -4384,12 +4384,17 @@ build_vec_init (tree base, tree maxindex, tree init,
>        else if (TREE_CODE (type) == ARRAY_TYPE)
>         {
>           if (init && !BRACE_ENCLOSED_INITIALIZER_P (init))
> -           sorry
> -             ("cannot initialize multi-dimensional array with initializer");
> -         elt_init = build_vec_init (build1 (INDIRECT_REF, type, base),
> -                                    0, init,
> -                                    explicit_value_init_p,
> -                                    0, complain);
> +           {
> +             if ((complain & tf_error))
> +               sorry ("cannot initialize multi-dimensional"
> +                      " array with initializer");
> +             elt_init = error_mark_node;

This shouldn't even be a sorry anymore; in build_aggr_init, we have

                permerror (init_loc, "array must be initialized "
                           "with a brace-enclosed initializer");

Let's make it a hard error here.

BTW, please include the word "PATCH" in the subject line of patch
submissions.  I will also see them faster if you CC me.

Jason