[Bug c/21342] New: [4.0/4.1 Regression] some incompatible external declarations not diagnosed

["jsm28 at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

My fix to bug 13801 caused some cases of incompatible declarations with external
linkage (in different scopes) not to be diagnosed.  pushdecl fails to update the
type in the external scope with the new information from the new declaration if
there was already a declaration in the current scope, or to check for
consistency with the type in the external scope in those circumstances.

Test 1:

int f(int (*)[]);
int g() { int f(int (*)[2]); }
int f(int (*)[3]);

Test 2:

extern int a[];
void f(void) { extern int a[]; extern int a[10]; }
extern int a[5];

Test 3:

extern int a[];
void f(void) { extern int a[10]; }
extern int a[5];

-- 
           Summary: [4.0/4.1 Regression] some incompatible external
                    declarations not diagnosed
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jsm28 at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21342