better casting

Author: topper-123

pandas/core/indexes/range.py

@@ -8,6 +8,7 @@
     Any,
     Callable,
     Hashable,
+    List,
     cast,
 )
 import warnings
@@ -761,10 +762,10 @@ def _concat(self, indexes: list[Index], name: Hashable) -> Index:
         if not all(isinstance(x, RangeIndex) for x in indexes):
             return super()._concat(indexes, name)
 
-        rng_indexes: list[RangeIndex] = [cast(RangeIndex, obj) for obj in indexes]
+        elif len(indexes) == 1:
+            return indexes[0]
 
-        if len(indexes) == 1:
-            return rng_indexes[0]
+        rng_indexes = cast(List[RangeIndex], indexes)
 
         start = step = next_ = None