hack string_concat_coercion

Author: dharanad

datafusion/expr/src/type_coercion/binary.rs

@@ -890,15 +890,21 @@ fn dictionary_coercion(
 /// 2. Data type of the other side should be able to cast to string type
 fn string_concat_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {
     use arrow::datatypes::DataType::*;
-    string_coercion_duplicate(lhs_type, rhs_type).or(match (lhs_type, rhs_type) {
-        (Utf8, from_type) | (from_type, Utf8) => {
-            string_concat_internal_coercion(from_type, &Utf8)
-        }
-        (LargeUtf8, from_type) | (from_type, LargeUtf8) => {
-            string_concat_internal_coercion(from_type, &LargeUtf8)
+    match (lhs_type, rhs_type) {
+        // If Utf8View is in any side, we coerce to Utf8.
+        (Utf8View, Utf8View | Utf8 | LargeUtf8) | (Utf8 | LargeUtf8, Utf8View) => {
+            Some(Utf8)
         }
-        _ => None,
-    })
+        _ => string_coercion(lhs_type, rhs_type).or(match (lhs_type, rhs_type) {
+            (Utf8, from_type) | (from_type, Utf8) => {
+                string_concat_internal_coercion(from_type, &Utf8)
+            }
+            (LargeUtf8, from_type) | (from_type, LargeUtf8) => {
+                string_concat_internal_coercion(from_type, &LargeUtf8)
+            }
+            _ => None,
+        }),
+    }
 }
 
 fn array_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {
@@ -939,20 +945,6 @@ fn string_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType>
     }
 }
 
-fn string_coercion_duplicate(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {
-    use arrow::datatypes::DataType::*;
-    match (lhs_type, rhs_type) {
-        // If Utf8View is in any side, we coerce to Utf8.
-        (Utf8View, Utf8View | Utf8 | LargeUtf8) | (Utf8 | LargeUtf8, Utf8View) => {
-            Some(Utf8)
-        }
-        // Then, if LargeUtf8 is in any side, we coerce to LargeUtf8.
-        (LargeUtf8, Utf8 | LargeUtf8) | (Utf8, LargeUtf8) => Some(LargeUtf8),
-        (Utf8, Utf8) => Some(Utf8),
-        _ => None,
-    }
-}
-
 fn numeric_string_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {
     use arrow::datatypes::DataType::*;
     match (lhs_type, rhs_type) {