diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 08cce3d7683..599784d22df 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -178,12 +178,6 @@ impl RuntimePhase {
     }
 }
 
-impl Display for MirPhase {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        f.write_str(self.name())
-    }
-}
-
 /// Where a specific `mir::Body` comes from.
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 #[derive(HashStable, TyEncodable, TyDecodable, TypeFoldable, TypeVisitable)]
diff --git a/compiler/rustc_mir_transform/src/pass_manager.rs b/compiler/rustc_mir_transform/src/pass_manager.rs
index 6288d006e94..c7a42056288 100644
--- a/compiler/rustc_mir_transform/src/pass_manager.rs
+++ b/compiler/rustc_mir_transform/src/pass_manager.rs
@@ -143,7 +143,7 @@ fn run_passes_inner<'tcx>(
 
         dump_mir_for_phase_change(tcx, body);
         if validate || new_phase == MirPhase::Runtime(RuntimePhase::Optimized) {
-            validate_body(tcx, body, format!("after phase change to {}", new_phase));
+            validate_body(tcx, body, format!("after phase change to {}", new_phase.name()));
         }
 
         body.pass_count = 1;