BUG: Preserve name in Index.astype

doc/source/whatsnew/v1.0.2.rst

@@ -37,7 +37,9 @@ Bug fixes
 - Using ``pd.NA`` with :meth:`DataFrame.to_json` now correctly outputs a null value instead of an empty object (:issue:`31615`)
 - Fixed bug in parquet roundtrip with nullable unsigned integer dtypes (:issue:`31896`).
 
+**Index**
 
+- Fixed bug where :meth:`Index.astype` would lose the name attribute when converting from ``Float64Index`` to ``Int64Index``. (:issue:`32013`)
 
 **Experimental dtypes**
 

pandas/core/indexes/numeric.py

@@ -376,7 +376,7 @@ def astype(self, dtype, copy=True):
             # TODO(jreback); this can change once we have an EA Index type
             # GH 13149
             arr = astype_nansafe(self.values, dtype=dtype)
-            return Int64Index(arr)
+            return Int64Index(arr, name=self.name)
         return super().astype(dtype, copy=copy)
 
     # ----------------------------------------------------------------

pandas/tests/indexes/base_class/test_astype.py

@@ -0,0 +1,21 @@
+import pytest
+
+from pandas import Index
+
+
+@pytest.mark.parametrize(
+    "from_type, to_type", [("float64", "int64"), ("int64", "float64")]
+)
+def test_astype_preserves_name(from_type, to_type):
+    idx = Index([1, 2], name="abc", dtype=from_type).astype(to_type)
+
+    assert idx.name == "abc"
+
+
+@pytest.mark.parametrize(
+    "from_type, to_type", [("float64", "int64"), ("int64", "float64")]
+)
+def test_copy_with_astype_preserves_name(from_type, to_type):
+    idx = Index([1, 2], name="abc", dtype=from_type).copy(dtype=to_type)
+
+    assert idx.name == "abc"