error parsing .pxd with derived class

[rmurri]

I cannot get Cython 0.11.1 to compile the following simple example::

 $ cat a.pxd
 cdef class A(object)
 cdef class B(A)

 $ cat a.pyx
 cdef class A(object):
      pass

 cdef class B(A):
      pass

 $ cat c.pyx
 from a cimport B

 cdef class C(B):
      pass

File "a.pyx" compiles correctly, but Cython chokes on "c.pxd"::

 $ cython -v a.pyx c.pyx
 Compiling /tmp/a.pyx
 Compiling /tmp/c.pyx
 Traceback (most recent call last):
   File "/home/rmurri/sw/Cython-0.11.1/bin/cython", line 8, in <module>
     main(command_line = 1)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/Main.py", line 734, in main
     result = compile(sources, options)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/Main.py", line 711, in compile
     return compile_multiple(source, options)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/Main.py", line 681, in compile_multiple
     result = run_pipeline(source, options)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/Main.py", line 543, in run_pipeline
     err, enddata = context.run_pipeline(pipeline, source)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/Main.py", line 198, in run_pipeline
     data = phase(data)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/Main.py", line 139, in generate_pyx_code
     module_node.process_implementation(options, result)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/ModuleNode.py", line 71, in process_implementation
     self.generate_c_code(env, options, result)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/ModuleNode.py", line 269, in generate_c_code
     self.generate_typeobj_definitions(env, code)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/ModuleNode.py", line 825, in generate_typeobj_definitions
     self.generate_new_function(scope, code)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/ModuleNode.py", line 885, in generate_new_function
     tp_new = TypeSlots.get_base_slot_function(scope, tp_slot)
   File "/home/rmurri/sw/Cython-0.11.1/Cython/Compiler/TypeSlots.py", line 429, in get_base_slot_function
     if scope.parent_scope is base_type.scope.parent_scope:
 AttributeError: 'NoneType' object has no attribute 'parent_scope'

 $ cython --version
 Cython version 0.11.1

Same error if I change "class A(object)" to "class A".

However, Cython compiles correcly if ": pass" is added to class prototypes in "a.pxd".

[robertwb]

The error should have been reported earlier that A was not fully defined in the .pxd file. (It must be, or one doesn't have enough information to subclass it elsewhere.)

 http://hg.cython.org/cython-devel/rev/41c5c91cbc5b