clang-tests/gcc-4_2-testsuite/src/objc.dg/class-2.m

/* Test super classes.  */
/* { dg-do compile } */

__attribute__((objc_root_class)) @interface supclass1
@end

__attribute__((objc_root_class)) @interface supclass2
@end

@interface class1 : supclass1
@end

@implementation class1 : supclass2 /* { dg-error "conflicting super class name" } */
@end /* { dg-error "previous declaration" "" { target *-*-* } 13 } */