tests/ui/structs/struct-fields-decl-dupe.rs - toolchain/rustc - Git at Google

 struct BuildData {
     foo: isize,
     foo: isize,
     //~^ ERROR field `foo` is already declared [E0124]
 }

 fn main() {
 }
	struct BuildData {
	foo: isize,
	foo: isize,
	//~^ ERROR field `foo` is already declared [E0124]
	}

	fn main() {
	}