diff --git a/src/types.rs b/src/types.rs
index e9b8e15303a..948e8fd063d 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -799,7 +799,7 @@ impl LintPass for InvalidUpcastComparisons {
     }
 }
 
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[derive(Copy, Clone, Debug, Eq)]
 enum FullInt {
     S(i64),
     U(u64),
@@ -820,6 +820,12 @@ impl FullInt {
     }
 }
 
+impl PartialEq for FullInt {
+    fn eq(&self, other: &Self) -> bool {
+        self.partial_cmp(other).expect("partial_cmp only returns Some(_)") == Ordering::Equal
+    }
+}
+
 impl PartialOrd for FullInt {
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
         Some(match (self, other) {