[Bug c/20655] New: Attempt to use undefined structure tag triggers no diagnostic

["jozef dot behran at krs dot sk" <gcc-bugzilla at gcc dot gnu dot org>]

/*** SNIP ***/  
/*  
  Place this file into `bug.c' (the code between the SNIP comments).  
  Then try `gcc -c -Wall bug.c'  
  The compiler silently transforms the type of the structure component 
  below to some kind of a generic pointer or something. 
  However it should output a diagnostic on the `UndefinedTag' identifier, 
  especially when -Wall is specified (as you can see above).  
  It is OK what the compiler does with this code but a warning should be  
  produced when the user really cares about them.  
  Without such a warning things often become confusing when someone  
  changes the tag in the declaration and forgets to update the tag name  
  in the pointers.  
*/  
  
typedef struct tagType {  
  struct UndefinedTag *Pointer;  
} TType;  
  
/*** SNIP ***/

-- 
           Summary: Attempt to use undefined structure tag triggers no
                    diagnostic
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jozef dot behran at krs dot sk
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20655