diff --git a/src/main/java/com/google/cloud/solutions/spannerddl/parser/ASTcheck_constraint.java b/src/main/java/com/google/cloud/solutions/spannerddl/parser/ASTcheck_constraint.java
index 2fdc5fb..d6418d0 100644
--- a/src/main/java/com/google/cloud/solutions/spannerddl/parser/ASTcheck_constraint.java
+++ b/src/main/java/com/google/cloud/solutions/spannerddl/parser/ASTcheck_constraint.java
@@ -51,7 +51,7 @@ public String toString() {
 
   @Override
   public boolean equals(Object other) {
-    if (other instanceof ASTcolumn_def) {
+    if (other instanceof ASTcheck_constraint) {
       return this.toString().equals(other.toString());
     }
     return false;