diff --git a/compiler/rustc_mir/src/dataflow/framework/fmt.rs b/compiler/rustc_mir/src/dataflow/framework/fmt.rs
index 0140a750544..35115ca9db7 100644
--- a/compiler/rustc_mir/src/dataflow/framework/fmt.rs
+++ b/compiler/rustc_mir/src/dataflow/framework/fmt.rs
@@ -33,7 +33,7 @@ pub trait DebugWithContext<C>: Eq + fmt::Debug {
         }
 
         write!(f, "\u{001f}-")?;
-        self.fmt_with(ctxt, f)
+        old.fmt_with(ctxt, f)
     }
 }