struct S { int alignof, mangleof; };
union U { int alignof, mangleof; };
enum E { alignof, mangleof };

test.c(1): Error: variable `test.S.alignof` `.alignof` property cannot be redefined
test.c(1): Error: variable `test.S.mangleof` `.mangleof` property cannot be redefined
test.c(2): Error: variable `test.U.alignof` `.alignof` property cannot be redefined
test.c(2): Error: variable `test.U.mangleof` `.mangleof` property cannot be redefined
test.c(3): Error: enum member `test.E.alignof` `.alignof` property cannot be redefined
test.c(3): Error: enum member `test.E.mangleof` `.mangleof` property cannot be redefined