diff --git a/heap_lang/lang.v b/heap_lang/lang.v
index 186439910c6b4597a37d46727aaa9cd6cb197f7c..9471d5b04c0c49bb6f2cc131cdd8a2b5b76c36a7 100644
--- a/heap_lang/lang.v
+++ b/heap_lang/lang.v
@@ -349,7 +349,7 @@ Proof.
  refine (cast_if (decide (of_val v1 = of_val v2))); abstract naive_solver.
 Defined.
 
-Instance expr_inhabited : Inhabited (expr) := populate (Lit LitUnit).
+Instance expr_inhabited : Inhabited expr := populate (Lit LitUnit).
 Instance val_inhabited : Inhabited val := populate (LitV LitUnit).
 
 Canonical Structure stateC := leibnizC state.