c/9070: Improper warning when casting from pointer to non-const array to const

[Joseph S. Myers]

The following reply was made to PR c/9070; it has been noted by GNATS.

From: "Joseph S. Myers" <jsm28@cam.ac.uk>
To: <126411@bugs.debian.org>
Cc: <gcc-gnats@gcc.gnu.org>,  <debian-gcc@lists.debian.org>, 
     <gcc-bugs@gcc.gnu.org>,  <agthorr@barsoom.org>
Subject: Re: c/9070: Improper warning when casting from pointer to non-const
 array to const
Date: Fri, 27 Dec 2002 22:38:40 +0000 (GMT)

 On Fri, 27 Dec 2002, Matthias Klose wrote:
 
 > gcc generates a warning for the following test program, that I believe
 > is inappropriate.  The warning is that it cannot implicitly cast from
 > (foo *) to (const foo *).  This occurs when foo is an array type.  The
 > sample program compiles without warnings if you remove the "const"
 > keyword, or if you remove the [16] making foo an array.
 
 It is an assignment from "pointer to array[16] of char" to "pointer to 
 array[16] of const char" rather than to "pointer to const array[16] of 
 char", by virtue of the requirement (6.7.3#8 in C99) that a type qualifier 
 applied to an array type applies instead to the element type.  Thus the 
 case of 6.5.16.1#1 that would be matched in the case of pointers to 
 nonarray types adding qualifiers is not matched, thus the warning.
 
 -- 
 Joseph S. Myers
 jsm28@cam.ac.uk