1 files changed, 29 insertions, 1 deletions
diff --git a/compiler/rustc_data_structures/src/fingerprint.rs b/compiler/rustc_data_structures/src/fingerprint.rs
index f8d631ce01e..aba0bbbac80 100644
--- a/compiler/rustc_data_structures/src/fingerprint.rs
+++ b/compiler/rustc_data_structures/src/fingerprint.rs
@@ -3,9 +3,10 @@ use rustc_serialize::{
     opaque::{self, EncodeResult},
     Decodable, Encodable,
 };
+use std::hash::{Hash, Hasher};
 use std::mem;
 
-#[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy)]
+#[derive(Eq, PartialEq, Ord, PartialOrd, Debug, Clone, Copy)]
 pub struct Fingerprint(u64, u64);
 
 impl Fingerprint {
@@ -76,6 +77,33 @@ impl ::std::fmt::Display for Fingerprint {
     }
 }
 
+impl Hash for Fingerprint {
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        state.write_fingerprint(self);
+    }
+}
+
+trait FingerprintHasher {
+    fn write_fingerprint(&mut self, fingerprint: &Fingerprint);
+}
+
+impl<H: Hasher> FingerprintHasher for H {
+    #[inline]
+    default fn write_fingerprint(&mut self, fingerprint: &Fingerprint) {
+        self.write_u64(fingerprint.0);
+        self.write_u64(fingerprint.1);
+    }
+}
+
+impl FingerprintHasher for crate::unhash::Unhasher {
+    #[inline]
+    fn write_fingerprint(&mut self, fingerprint: &Fingerprint) {
+        // `Unhasher` only wants a single `u64`
+        self.write_u64(fingerprint.0);
+    }
+}
+
 impl stable_hasher::StableHasherResult for Fingerprint {
     #[inline]
     fn finish(hasher: stable_hasher::StableHasher) -> Self {