User-defined function can't identify Date and TimeStamp when both exist

     evaluate(Date d);
     evaluate(TIMESTAMP t);

The table  is :
    CREATE TABLE file_source (
    name VARCHAR,
    d    TIMESTAMP
   ) 

CREATE TEMPORARY function 'TESTUDF' AS 'com.netease.sloth.server.actor.TestUDF';
INSERT INTO db_sink SELECT name, TESTUDF(d) FROM file_source; 

java.lang.AssertionError
	at org.apache.calcite.sql.type.SqlTypeExplicitPrecedenceList.compareTypePrecedence(SqlTypeExplicitPrecedenceList.java:153)
	at org.apache.calcite.sql.SqlUtil.bestMatch(SqlUtil.java:627)
	at org.apache.calcite.sql.SqlUtil.filterRoutinesByTypePrecedence(SqlUtil.java:593)
	at org.apache.calcite.sql.SqlUtil.lookupSubjectRoutines(SqlUtil.java:447)
	at org.apache.calcite.sql.SqlUtil.lookupRoutine(SqlUtil.java:371)
	at org.apache.calcite.sql.SqlFunction.deriveType(SqlFunction.java:245)
	at org.apache.calcite.sql.SqlFunction.deriveType(SqlFunction.java:223)
	at org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:4882)
	at org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:4869)
	at org.apache.calcite.sql.SqlCall.accept(SqlCall.java:137)
	at org.apache.calcite.sql.validate.SqlValidatorImpl.deriveTypeImpl(SqlValidatorImpl.java:1580)
	at org.apache.calcite.sql.validate.SqlValidatorImpl.deriveType(SqlValidatorImpl.java:1565)
	at org.apache.calcite.sql.validate.SqlValidatorImpl.expandSelectItem(SqlValidatorImpl.java:447)
	at org.apache.calcite.sql.validate.SqlValidatorImpl.validateSelectList(SqlValidatorImpl.java:3671)
	at org.apache.calcite.sql.validate.SqlValidatorImpl.validateSelect(SqlValidatorImpl.java:3180)
	at org.apache.calcite.sql.validate.SqlValidatorImpl.validateInsert(SqlValidatorImpl.java:3845)
	at org.apache.calcite.sql.SqlInsert.validate(SqlInsert.java:148)
	at org.apache.calcite.sql.validate.SqlValidatorImpl.validateScopedExpression(SqlValidatorImpl.java:887)
	at org.apache.calcite.sql.validate.SqlValidatorImpl.validate(SqlValidatorImpl.java:597)
	at org.apache.calcite.prepare.PlannerImpl.validate(PlannerImpl.java:188)
	at com.netease.sloth.server.plan.SlothPlanner.parseSqlDml(SlothPlanner.java:670)
	at com.netease.sloth.server.actor.AbstractJobManager.handle(AbstractJobManager.java:165)
	at com.netease.sloth.server.actor.MyTest.testRunJobLocal(MyTest.java:60)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:117)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:262)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:84)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)