1 files changed, 8 insertions, 0 deletions
diff --git a/compiler/rustc_data_structures/src/stable_hasher.rs b/compiler/rustc_data_structures/src/stable_hasher.rs
index ae4836645..e0d77cdae 100644
--- a/compiler/rustc_data_structures/src/stable_hasher.rs
+++ b/compiler/rustc_data_structures/src/stable_hasher.rs
@@ -486,6 +486,14 @@ impl<HCX> ToStableHashKey<HCX> for String {
     }
 }
 
+impl<HCX, T1: ToStableHashKey<HCX>, T2: ToStableHashKey<HCX>> ToStableHashKey<HCX> for (T1, T2) {
+    type KeyType = (T1::KeyType, T2::KeyType);
+    #[inline]
+    fn to_stable_hash_key(&self, hcx: &HCX) -> Self::KeyType {
+        (self.0.to_stable_hash_key(hcx), self.1.to_stable_hash_key(hcx))
+    }
+}
+
 impl<CTX> HashStable<CTX> for bool {
     #[inline]
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {