use is_integer in df.insert

pandas/core/frame.py

@@ -4800,7 +4800,7 @@ def insert(
         if not allow_duplicates and column in self.columns:
             # Should this be a different kind of error??
             raise ValueError(f"cannot insert {column}, already exists")
-        if not isinstance(loc, int):
+        if not is_integer(loc):
             raise TypeError("loc must be int")
 
         if isinstance(value, DataFrame) and len(value.columns) > 1:

pandas/tests/frame/indexing/test_insert.py

@@ -110,3 +110,8 @@ def test_insert_frame(self):
         )
         with pytest.raises(ValueError, match=msg):
             df.insert(1, "newcol", df)
+
+    def test_insert_int64_loc(self):
+        df = DataFrame({"a": [1, 2]})
+        df.insert(np.int64(0), "b", 0)
+        tm.assert_frame_equal(df, DataFrame({"b": [0, 0], "a": [1, 2]}))