diff --git a/asterixdb/asterix-metadata/src/main/java/org/apache/asterix/metadata/functions/ExternalFunctionCompilerUtil.java b/asterixdb/asterix-metadata/src/main/java/org/apache/asterix/metadata/functions/ExternalFunctionCompilerUtil.java
index 90c0de3..3d80d0f 100644
--- a/asterixdb/asterix-metadata/src/main/java/org/apache/asterix/metadata/functions/ExternalFunctionCompilerUtil.java
+++ b/asterixdb/asterix-metadata/src/main/java/org/apache/asterix/metadata/functions/ExternalFunctionCompilerUtil.java
@@ -163,8 +163,7 @@
                     @Override
                     public IAType computeType(ILogicalExpression expression, IVariableTypeEnvironment env,
                             IMetadataProvider<?, ?> metadataProvider) throws AlgebricksException {
-
-                        return new AUnorderedListType(type, type.getTypeName());
+                        return new AUnorderedListType(((AUnorderedListType) type).getItemType(), type.getTypeName());
                     }
 
                 };
diff --git a/asterixdb/asterix-metadata/src/test/java/org/apache/asterix/metadata/functions/ExternalFunctionCompilerUtilTest.java b/asterixdb/asterix-metadata/src/test/java/org/apache/asterix/metadata/functions/ExternalFunctionCompilerUtilTest.java
new file mode 100644
index 0000000..5e5b26a
--- /dev/null
+++ b/asterixdb/asterix-metadata/src/test/java/org/apache/asterix/metadata/functions/ExternalFunctionCompilerUtilTest.java
@@ -0,0 +1,51 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.asterix.metadata.functions;
+
+import java.util.LinkedList;
+
+import org.apache.asterix.common.transactions.TxnId;
+import org.apache.asterix.metadata.MetadataTransactionContext;
+import org.apache.asterix.metadata.entities.Function;
+import org.apache.asterix.om.types.AUnorderedListType;
+import org.apache.asterix.om.types.BuiltinType;
+import org.apache.asterix.om.types.IAType;
+import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ExternalFunctionCompilerUtilTest {
+    @Test
+    public void test() throws AlgebricksException {
+        // given
+        MetadataTransactionContext txnCtx = new MetadataTransactionContext(new TxnId(1));
+        Function function =
+                new Function("test", "test", 0, new LinkedList<>(), "{{ASTRING}}", "", "JAVA", "SCALAR", null);
+
+        // when
+        ExternalScalarFunctionInfo info =
+                (ExternalScalarFunctionInfo) ExternalFunctionCompilerUtil.getExternalFunctionInfo(txnCtx, function);
+        IAType type = info.getResultTypeComputer().computeType(null, null, null);
+
+        // then
+        IAType expectedType = new AUnorderedListType(BuiltinType.ASTRING, "AUnorderedList");
+        Assert.assertEquals(expectedType, info.getReturnType());
+        Assert.assertEquals(expectedType, type);
+    }
+}