Revert "Make cpdef methods overridable in Python classes with slots (which do not have a dict)."

This reverts commit eb0e4666.

CHANGES.rst

@@ -10,9 +10,6 @@ Bugs fixed
 
 * Set iteration was broken in non-CPython since 0.28.
 
-* Overriding cpdef methods did not work in Python subclasses with slots.
-  (Github issue #1771)
-
 * ``UnicodeEncodeError`` in Py2 when ``%s`` formatting is optimised for
   unicode strings.  (Github issue #2276)
 

Cython/Compiler/Nodes.py

@@ -4337,9 +4337,7 @@ class OverrideCheckNode(StatNode):
         if self.py_func.is_module_scope:
             code.putln("else {")
         else:
-            code.putln("else if (unlikely((Py_TYPE(%s)->tp_dictoffset != 0)"
-                       " || (Py_TYPE(%s)->tp_flags & (Py_TPFLAGS_IS_ABSTRACT | Py_TPFLAGS_HEAPTYPE)))) {" % (
-                self_arg, self_arg))
+            code.putln("else if (unlikely(Py_TYPE(%s)->tp_dictoffset != 0)) {" % self_arg)
         func_node_temp = code.funcstate.allocate_temp(py_object_type, manage_ref=True)
         self.func_node.set_cname(func_node_temp)
         # need to get attribute manually--scope would return cdef method

tests/run/cpdef_method_override.pyx

-# mode: run
-# tag: cpdef
-# ticket: gh-1771
-
-cdef class BaseType:
-    """
-    >>> BaseType().callmeth()
-    BaseType.meth
-    """
-    def callmeth(self):
-        return self.meth()
-    cpdef meth(self):
-        print("BaseType.meth")
-
-
-class PyClass(BaseType):
-    """
-    >>> PyClass().callmeth()
-    PyClass.meth
-    """
-    def meth(self):
-        print("PyClass.meth")
-
-
-class PySlotsClass(BaseType):
-    """
-    >>> PySlotsClass().callmeth()
-    PySlotsClass.meth
-    """
-    __slots__ = []
-
-    def meth(self):
-        print("PySlotsClass.meth")