diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/PredicatePropagation.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/PredicatePropagation.java
index 45831abbee906b..72e9023dc45df5 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/PredicatePropagation.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/PredicatePropagation.java
@@ -88,6 +88,9 @@ public ComparisonInferInfo(InferType inferType,
     public Set<Expression> infer(Set<Expression> predicates) {
         Set<Expression> inferred = Sets.newHashSet();
         for (Expression predicate : predicates) {
+            // if we support more infer predicate expression type, we should impl withInferred() method.
+            // And should add inferred props in withChildren() method just like ComparisonPredicate,
+            // and it's subclass, to mark the predicate is from infer.
             if (!(predicate instanceof ComparisonPredicate)) {
                 continue;
             }
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Expression.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Expression.java
index ebfd57c5c65db9..1ce12fc0efac03 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Expression.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Expression.java
@@ -242,7 +242,7 @@ public Expression withChildren(List<Expression> children) {
     }
 
     public Expression withInferred(boolean inferred) {
-        throw new RuntimeException();
+        throw new RuntimeException("current expression has not impl the withInferred method");
     }
 
     /**