[Bug fortran/46459] ICE (segfault): Invalid read in compare_actual_formal [error recovery]

[anlauf at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46459

--- Comment #7 from Harald Anlauf <anlauf at gmx dot de> ---
The patch of comment #1 (adjusted to current trunk) regtests cleanly
for me.

(In reply to Mikael Morin from comment #5)
> The initial test doesn't lead to a segfault any more.
> 
> It is now rejected with:
> comment_0.f90:7.8:
> 
> call sub(1)
>         1
> Error: Explicit interface required for 'sub' at (1): volatile argument

I think this is correct, see below (*).

> 
> However, the following variant is also rejected with the same error:
> 
>  call sub(1)
> contains
>   subroutine sub(j)
>    integer, volatile :: j
>   end subroutine sub
> end

I do not get any error for this case, which is correct.

(*) The requirement for an explicit interface is described in F2008,
section 12.4.2.2 (2a), and is already properly handled by
gfc_explicit_interface_required().

I threw this testcase at the Cray compiler:

% cat pr46459.f90
  call sub (1)
contains
  subroutine sub (j)
    integer, volatile :: j
  end subroutine sub
end

subroutine sub1 ()
  call sub2 (1)         ! { dg-error "Explicit interface required" }
end subroutine sub1
subroutine sub2 (j)
  integer, volatile :: j
end subroutine sub2

subroutine sub3 ()
  interface
     subroutine sub2 (j)
       integer, volatile :: j
     end subroutine sub2
  end interface
  call sub2 (1)
end subroutine sub3


% ftn pr46459.f90   

subroutine sub2 (j)
           ^        
ftn-954 crayftn: ERROR SUB2, File = pr46459.f90, Line = 11, Column = 12 
  Procedure "SUB2", referenced at line 9 (pr46459.f90) must have an explicit
interface because one or more arguments have the VOLATILE attribute.


This would agree with the patched trunk:

pr46459.f90:9:11:

   call sub2 (1)         ! { dg-error "Explicit interface required" }
           1
Error: Explicit interface required for 'sub2' at (1): volatile argument