remove err

Author: Jiayu Liu

datafusion/src/physical_plan/functions.rs

@@ -1371,7 +1371,6 @@ impl fmt::Display for ScalarFunctionExpr {
 type NullColumnarValue = ColumnarValue;
 
 impl From<&RecordBatch> for NullColumnarValue {
-    type Error = DataFusionError;
     fn from(batch: &RecordBatch) -> Self {
         let num_rows = batch.num_rows();
         ColumnarValue::Array(Arc::new(NullArray::new(num_rows)))