ENH: Clarifies wording of warning message for column name collision

Author: deniederhut

pandas/core/generic.py

@@ -1825,9 +1825,9 @@ def _slice(self, slobj, axis=0, kind=None):
 
     def _set_item(self, key, value):
         if callable(getattr(self, key, None)):
-            warnings.warn("Pandas doesn't allow attribute-like access to "
-                          "columns whose names collide with methods",
-                          stacklevel=3)
+            warnings.warn("Column name '{key}' collides with a built-in "
+                          "method, which will cause unexpected attribute "
+                          "behavior".format(key=key), stacklevel=3)
         self._data.set(key, value)
         self._clear_item_cache()