[Bug c/106406] New: _Static_assert declaration can not be first of for-triplet

[Bug c/106406] New: _Static_assert declaration can not be first of for-triplet

[chumarshal at foxmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106406

            Bug ID: 106406
           Summary: _Static_assert declaration can not be first of
                    for-triplet
           Product: gcc
           Version: rust/master
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chumarshal at foxmail dot com
  Target Milestone: ---

int main()
{
    int i = 4;
    for (_Static_assert (3, "This is a three"); i < 7; i++) {
        i += 2;
    }
 }


Gcc can build successfully, but it does not follow C spec:

6.8.5 Iteration statements
(Constraints)
The declaration part of a for statement shall only declare identifiers for
objects having storage class auto or register.

[Bug c/106406] _Static_assert declaration can not be first of for-triplet

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106406

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
it doesn't declare anything so why should it be invalid?

[Bug c/106406] _Static_assert declaration can not be first of for-triplet

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106406

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
clang rejects it while both ICC and MSVC accepts it as being valid.


6.7.10 Static assertions
...
Semantics
...
If the value of the constant expression compares unequal to 0, the declaration
has no effect.

---
There is no identifiers defined so the constraint of Iteration statements is
not violated as far as I can tell.

So I do think this is a clang bug so closing as invalid.

[Bug c/106406] _Static_assert declaration can not be first of for-triplet

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106406

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
One thing I noticed with clang is that it is the rejected inside the parser
rather than later on with the semantic analysis meaning I think it was
overlooked for clang's parser.

[Bug c/106406] _Static_assert declaration can not be first of for-triplet

[chumarshal at foxmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106406

--- Comment #4 from marshal <chumarshal at foxmail dot com> ---
(In reply to marshal from comment #0)
> int main()
> {
>     int i = 4;
>     for (_Static_assert (3, "This is a three"); i < 7; i++) {
>         i += 2;
>     }
>  }
> 
> 
> Gcc can build successfully, but it does not follow C spec:
> 
> 6.8.5 Iteration statements
> (Constraints)
> The declaration part of a for statement shall only declare identifiers for
> objects having storage class auto or register.

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