[Cython] overriding cpdef methods

[Stefan Behnel]

Hi,

while cythonising Visitor.py with an external .pxd, I noticed that I can't
currently override a cpdef method in a subtype. The hierarchy is like this:

--------------------
cdef class BasicVisitor:
    cdef dict dispatch_table
    cpdef visit(self, obj)

cdef class TreeVisitor(BasicVisitor):
    cdef public list access_path
    cpdef visitchild(self, child, parent, attrname, idx)
    cpdef visitchildren(self, parent, attrs=*)    # <-----

cdef class VisitorTransform(TreeVisitor):
    cdef object _super_visitchildren
    cpdef visitchildren(self, parent, attrs=*)    # <-----
    cpdef recurse_to_children(self, node)
--------------------

and the error I get out of Symtab.py is:

------------------------------------------------------------
...
    def visitchildren(self, parent, attrs=None):
   ^
------------------------------------------------------------

.../Cython/Compiler/Visitor.py:150:4: Self argument of C method does not
match parent type

Does anyone know if this is an anticipated problem, or just a bug that
needs fixing? I don't see any general obstacles for overriding cpdef methods.

Stefan