diff --git a/compiler/rustc_middle/src/ty/relate.rs b/compiler/rustc_middle/src/ty/relate.rs
index 8efb88d40406..9c48f05617e0 100644
--- a/compiler/rustc_middle/src/ty/relate.rs
+++ b/compiler/rustc_middle/src/ty/relate.rs
@@ -214,6 +214,19 @@ impl<'tcx> Relate<'tcx> for ast::Constness {
     }
 }
 
+impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for ty::ConstnessAnd<T> {
+    fn relate<R: TypeRelation<'tcx>>(
+        relation: &mut R,
+        a: ty::ConstnessAnd<T>,
+        b: ty::ConstnessAnd<T>,
+    ) -> RelateResult<'tcx, ty::ConstnessAnd<T>> {
+        Ok(ty::ConstnessAnd {
+            constness: relation.relate(a.constness, b.constness)?,
+            value: relation.relate(a.value, b.value)?,
+        })
+    }
+}
+
 impl<'tcx> Relate<'tcx> for ast::Unsafety {
     fn relate<R: TypeRelation<'tcx>>(
         relation: &mut R,