Re: [PATCH] c++: Don't quote nothrow in diagnostic

[Richard Biener <richard.guenther@gmail.com>]

On Fri, Sep 23, 2022 at 8:41 PM Marek Polacek via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> In <https://gcc.gnu.org/pipermail/gcc-patches/2022-September/602057.html>
> Jason noticed that we quote "nothrow" in diagnostics even though it's
> not a keyword in C++.  Just removing the quotes didn't work because
> then -Wformat-diag complains, so this patch replaces it with "no-throw".
>
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

That doesn't look like an improvement to me.  Can we quote 'nothrow()' instead?
I'd rather leave it alone than changing it to no-throw.  Why does -Wformat-diag
complain?  If we shouldn't quote nothrow that should be adjusted?

>
> gcc/cp/ChangeLog:
>
>         * constraint.cc (diagnose_trait_expr): Say "no-throw" (without quotes)
>         rather than "nothrow" in quotes.
>
> gcc/testsuite/ChangeLog:
>
>         * g++.dg/cpp2a/concepts-traits3.C: Adjust expected diagnostics.
> ---
>  gcc/cp/constraint.cc                          | 14 +++++++-------
>  gcc/testsuite/g++.dg/cpp2a/concepts-traits3.C |  8 ++++----
>  2 files changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> index 5839bfb4b52..136647f7c9e 100644
> --- a/gcc/cp/constraint.cc
> +++ b/gcc/cp/constraint.cc
> @@ -3592,13 +3592,13 @@ diagnose_trait_expr (tree expr, tree args)
>    switch (TRAIT_EXPR_KIND (expr))
>      {
>      case CPTK_HAS_NOTHROW_ASSIGN:
> -      inform (loc, "  %qT is not %<nothrow%> copy assignable", t1);
> +      inform (loc, "  %qT is not no-throw copy assignable", t1);
>        break;
>      case CPTK_HAS_NOTHROW_CONSTRUCTOR:
> -      inform (loc, "  %qT is not %<nothrow%> default constructible", t1);
> +      inform (loc, "  %qT is not no-throw default constructible", t1);
>        break;
>      case CPTK_HAS_NOTHROW_COPY:
> -      inform (loc, "  %qT is not %<nothrow%> copy constructible", t1);
> +      inform (loc, "  %qT is not no-throw copy constructible", t1);
>        break;
>      case CPTK_HAS_TRIVIAL_ASSIGN:
>        inform (loc, "  %qT is not trivially copy assignable", t1);
> @@ -3674,7 +3674,7 @@ diagnose_trait_expr (tree expr, tree args)
>        inform (loc, "  %qT is not trivially assignable from %qT", t1, t2);
>        break;
>      case CPTK_IS_NOTHROW_ASSIGNABLE:
> -      inform (loc, "  %qT is not %<nothrow%> assignable from %qT", t1, t2);
> +      inform (loc, "  %qT is not no-throw assignable from %qT", t1, t2);
>        break;
>      case CPTK_IS_CONSTRUCTIBLE:
>        if (!t2)
> @@ -3690,9 +3690,9 @@ diagnose_trait_expr (tree expr, tree args)
>        break;
>      case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
>        if (!t2)
> -       inform (loc, "  %qT is not %<nothrow%> default constructible", t1);
> +       inform (loc, "  %qT is not no-throw default constructible", t1);
>        else
> -       inform (loc, "  %qT is not %<nothrow%> constructible from %qE", t1, t2);
> +       inform (loc, "  %qT is not no-throw constructible from %qE", t1, t2);
>        break;
>      case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS:
>        inform (loc, "  %qT does not have unique object representations", t1);
> @@ -3701,7 +3701,7 @@ diagnose_trait_expr (tree expr, tree args)
>        inform (loc, "  %qT is not convertible from %qE", t2, t1);
>        break;
>      case CPTK_IS_NOTHROW_CONVERTIBLE:
> -       inform (loc, "  %qT is not %<nothrow%> convertible from %qE", t2, t1);
> +       inform (loc, "  %qT is not no-throw convertible from %qE", t2, t1);
>        break;
>      case CPTK_REF_CONSTRUCTS_FROM_TEMPORARY:
>        inform (loc, "  %qT is not a reference that binds to a temporary "
> diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-traits3.C b/gcc/testsuite/g++.dg/cpp2a/concepts-traits3.C
> index f20608b6918..6ac849d71fd 100644
> --- a/gcc/testsuite/g++.dg/cpp2a/concepts-traits3.C
> +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-traits3.C
> @@ -21,7 +21,7 @@ concept TriviallyAssignable = __is_trivially_assignable(T, U);
>
>  template<class T, class U>
>  concept NothrowAssignable = __is_nothrow_assignable(T, U);
> -// { dg-message "'S' is not 'nothrow' assignable from 'int'" "" { target *-*-* } .-1  }
> +// { dg-message "'S' is not no-throw assignable from 'int'" "" { target *-*-* } .-1  }
>
>  template<class T, class... Args>
>  concept Constructible = __is_constructible(T, Args...);
> @@ -37,9 +37,9 @@ concept TriviallyConstructible = __is_trivially_constructible(T, Args...);
>
>  template<class T, class... Args>
>  concept NothrowConstructible = __is_nothrow_constructible(T, Args...);
> -// { dg-message "'S' is not 'nothrow' default constructible" "" { target *-*-* } .-1  }
> -// { dg-message "'S' is not 'nothrow' constructible from 'int'" "" { target *-*-* } .-2  }
> -// { dg-message "'S' is not 'nothrow' constructible from 'int, char'" "" { target *-*-* } .-3  }
> +// { dg-message "'S' is not no-throw default constructible" "" { target *-*-* } .-1  }
> +// { dg-message "'S' is not no-throw constructible from 'int'" "" { target *-*-* } .-2  }
> +// { dg-message "'S' is not no-throw constructible from 'int, char'" "" { target *-*-* } .-3  }
>
>  template<class T>
>  concept UniqueObjReps = __has_unique_object_representations(T);
>
> base-commit: 8a7bcf95a82c3dd68bd4bcfbd8432eb970575bc2
> --
> 2.37.3
>