diff --git a/src/test/ui/deriving/deriving-hash.rs b/src/test/ui/deriving/deriving-hash.rs index 8b51370bca502..16738ec4ae4ec 100644 --- a/src/test/ui/deriving/deriving-hash.rs +++ b/src/test/ui/deriving/deriving-hash.rs @@ -44,6 +44,17 @@ fn fake_hash(v: &mut Vec, a: A) { a.hash(&mut FakeHasher(v)); } +struct OnlyOneByteHasher; +impl Hasher for OnlyOneByteHasher { + fn finish(&self) -> u64 { + unreachable!() + } + + fn write(&mut self, bytes: &[u8]) { + assert_eq!(bytes.len(), 1); + } +} + fn main() { let person1 = Person { id: 5, @@ -73,4 +84,13 @@ fn main() { let mut v = vec![]; fake_hash(&mut v, SingleVariantEnum::A(17)); assert_eq!(vec![17], v); + + // issue #39137 + #[repr(u8)] + #[derive(Hash)] + enum E { + A, + B, + } + E::A.hash(&mut OnlyOneByteHasher); }