if r.Name.Kind != "type" {
			error_(r.Pos(), "expression C.%s used as type", fixGo(r.Name.Go))
		} else if r.Name.Type == nil {
			// Use of C.enum_x, C.struct_x or C.union_x without C definition.
			// GCC won't raise an error when using pointers to such unknown types.
			error_(r.Pos(), "type C.%s: undefined C type '%s'", fixGo(r.Name.Go), r.Name.C)
		}
	default:
		if r.Name.Kind == "func" {