tests/headers/constify-all-enums.h - third_party/github.com/rust-lang/rust-bindgen - Git at Google

 // bindgen-flags: --constified-enum foo

 enum foo {
   THIS,
   SHOULD_BE,
   A_CONSTANT,
 };

 struct bar {
   enum foo this_should_work;
 };
	// bindgen-flags: --constified-enum foo

	enum foo {
	THIS,
	SHOULD_BE,
	A_CONSTANT,
	};

	struct bar {
	enum foo this_should_work;
	};