Disallow final cpdef methods in non-final extension type

Cython/Compiler/Nodes.py

@@ -2244,7 +2244,11 @@ class DefNode(FuncDefNode):
         #print "DefNode.declare_pyfunction:", self.name, "in", env ###
         name = self.name
         entry = env.lookup_here(name)
-        if entry and entry.type.is_cfunction and not entry.is_builtin_cmethod and not self.is_wrapper:
+        if entry:
+            if entry.is_final_cmethod and not env.parent_type.is_final_type:
+                error(self.pos, "Only final type could have final cpdef method")
+            if (entry.type.is_cfunction and not entry.is_builtin_cmethod
+                and not self.is_wrapper):
                 warning(self.pos, "Overriding cdef method with def method.", 5)
         entry = env.declare_pyfunction(name, self.pos, allow_redefine=not self.is_wrapper)
         self.entry = entry

tests/errors/final_methods.pyx

@@ -16,10 +16,7 @@ cdef class SubType(BaseClass):
     cdef cdef_method(self):
         pass
 
-    cpdef cpdef_method(self):
-        pass
-
 _ERRORS = """
+11:10: Only final type could have final cpdef method
 16:9: Overriding final methods is not allowed
-19:10: Overriding final methods is not allowed
 """

tests/run/final_method_T586.pyx

@@ -3,21 +3,20 @@
 
 cimport cython
 
-cdef class FinalMethods(object):
+@cython.final
+cdef class FinalType(object):
     """
-    >>> obj = FinalMethods()
+    >>> obj = FinalType()
     >>> obj.test_cdef()
     >>> obj.test_cpdef()
     """
 
     @cython.test_assert_path_exists("//CFuncDefNode[@entry.is_final_cmethod=True]")
-    @cython.final
     cdef cdef_method(self):
         pass
 
     @cython.test_assert_path_exists("//CFuncDefNode[@entry.is_final_cmethod=True]")
     @cython.test_fail_if_path_exists("//CFuncDefNode//OverrideCheckNode")
-    @cython.final
     cpdef cpdef_method(self):
         pass
 
@@ -30,16 +29,27 @@ cdef class FinalMethods(object):
         self.cpdef_method()
 
 
-cdef class SubType(FinalMethods):
+cdef class BaseTypeWithFinalMethods(object):
     """
-    >>> obj = SubType()
+    >>> obj = BaseTypeWithFinalMethods()
     >>> obj.test_cdef()
-    >>> obj.test_cpdef()
     """
+
+    @cython.test_assert_path_exists("//CFuncDefNode[@entry.is_final_cmethod=True]")
+    @cython.final
+    cdef cdef_method(self):
+        pass
+
     @cython.test_assert_path_exists("//AttributeNode[@entry.is_final_cmethod=True]")
     def test_cdef(self):
         self.cdef_method()
 
+
+cdef class SubType(BaseTypeWithFinalMethods):
+    """
+    >>> obj = SubType()
+    >>> obj.test_cdef()
+    """
     @cython.test_assert_path_exists("//AttributeNode[@entry.is_final_cmethod=True]")
-    def test_cpdef(self):
-        self.cpdef_method()
+    def test_cdef(self):
+        self.cdef_method()