diff --git a/fe/src/main/java/org/apache/impala/analysis/CaseExpr.java b/fe/src/main/java/org/apache/impala/analysis/CaseExpr.java
index 44406901f..3d9666225 100644
--- a/fe/src/main/java/org/apache/impala/analysis/CaseExpr.java
+++ b/fe/src/main/java/org/apache/impala/analysis/CaseExpr.java
@@ -127,16 +127,17 @@ public class CaseExpr extends Expr {
         if (candidate.isNullLiteral()) {
           // An example case is DECODE(foo, NULL, bar), since NULLs are considered
           // equal, this becomes CASE WHEN foo IS NULL THEN bar END.
-          children_.add(encodedIsNull);
+          children_.add(encodedIsNull.clone());
         } else {
           children_.add(new BinaryPredicate(
-              BinaryPredicate.Operator.EQ, encoded, candidate));
+              BinaryPredicate.Operator.EQ, encoded.clone(), candidate));
         }
       } else {
         children_.add(new CompoundPredicate(CompoundPredicate.Operator.OR,
             new CompoundPredicate(CompoundPredicate.Operator.AND,
-                encodedIsNull, new IsNullPredicate(candidate, false)),
-            new BinaryPredicate(BinaryPredicate.Operator.EQ, encoded, candidate)));
+                encodedIsNull.clone(), new IsNullPredicate(candidate, false)),
+            new BinaryPredicate(BinaryPredicate.Operator.EQ, encoded.clone(),
+                candidate)));
       }
 
       // Add the value
@@ -148,6 +149,11 @@ public class CaseExpr extends Expr {
       hasElseExpr_ = true;
       children_.add(decodeExpr.getChild(childIdx));
     }
+
+    // Check that these exprs were cloned above, as reusing the same Expr object in
+    // different places can lead to bugs, eg. if the Expr has multiple parents, they may
+    // try to cast it to different types.
+    Preconditions.checkState(!contains(encoded) && !contains(encodedIsNull));
   }
 
   /**
diff --git a/fe/src/main/java/org/apache/impala/common/TreeNode.java b/fe/src/main/java/org/apache/impala/common/TreeNode.java
index 3231e332e..730fd4411 100644
--- a/fe/src/main/java/org/apache/impala/common/TreeNode.java
+++ b/fe/src/main/java/org/apache/impala/common/TreeNode.java
@@ -157,6 +157,15 @@ public abstract class TreeNode<NodeType extends TreeNode<NodeType>> {
     return false;
   }
 
+  /**
+   * Returns true if this node or any of its children is 'node'.
+   */
+  public boolean contains(NodeType node) {
+    if (this == node) return true;
+    for (NodeType child: children_) if (child.contains(node)) return true;
+    return false;
+  }
+
   /**
    * For each node in nodeList, return true if any subexpression satisfies
    * contains('predicate').
diff --git a/testdata/workloads/functional-query/queries/QueryTest/exprs.test b/testdata/workloads/functional-query/queries/QueryTest/exprs.test
index 4b1ba7690..ed3c9d9ce 100644
--- a/testdata/workloads/functional-query/queries/QueryTest/exprs.test
+++ b/testdata/workloads/functional-query/queries/QueryTest/exprs.test
@@ -2649,3 +2649,19 @@ select count(*) from functional.alltypestiny group by concat(uuid(), "_test")
 ---- TYPES
 BIGINT
 ====
+---- QUERY
+# IMPALA-4716: Tests that decode with 'when' values of different types is analyzed
+# correctly when expr rewrites are enabled.
+select decode(0, 1, 0, id, 1, 2) a from functional.alltypestiny order by a
+---- RESULTS
+1
+2
+2
+2
+2
+2
+2
+2
+---- TYPES
+TINYINT
+====