ScalarOperatorGens.numericCasting is not compatible with legacy behavior

// code placeholder
@Test
def test(): Unit ={
  testSqlApi("rand(1) + 1","")
} 

// code placeholder
org.apache.flink.table.planner.codegen.CodeGenException: Unsupported casting from DOUBLE to DOUBLE NOT NULL.
    at org.apache.flink.table.planner.codegen.calls.ScalarOperatorGens$.numericCasting(ScalarOperatorGens.scala:1734)
    at org.apache.flink.table.planner.codegen.calls.ScalarOperatorGens$.generateBinaryArithmeticOperator(ScalarOperatorGens.scala:85)
    at org.apache.flink.table.planner.codegen.ExprCodeGenerator.generateCallExpression(ExprCodeGenerator.scala:507)
    at org.apache.flink.table.planner.codegen.ExprCodeGenerator.visitCall(ExprCodeGenerator.scala:481)
    at org.apache.flink.table.planner.codegen.ExprCodeGenerator.visitCall(ExprCodeGenerator.scala:57)
    at org.apache.calcite.rex.RexCall.accept(RexCall.java:174)
    at org.apache.flink.table.planner.codegen.ExprCodeGenerator.$anonfun$visitCall$1(ExprCodeGenerator.scala:478)
    at scala.collection.TraversableLike.$anonfun$map$1(TraversableLike.scala:233)
    at scala.collection.mutable.ResizableArray.foreach(ResizableArray.scala:58)
    at scala.collection.mutable.ResizableArray.foreach$(ResizableArray.scala:51)
    at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
    at scala.collection.TraversableLike.map(TraversableLike.scala:233)
    at scala.collection.TraversableLike.map$(TraversableLike.scala:226)
    at scala.collection.AbstractTraversable.map(Traversable.scala:104)
    at org.apache.flink.table.planner.codegen.ExprCodeGenerator.visitCall(ExprCodeGenerator.scala:469)
...