[Cython] CF based type inference

[Robert Bradshaw]

On Wed, May 9, 2012 at 6:33 AM, Stefan Behnel <stefan_ml at behnel.de> wrote:
> mark florisson, 09.05.2012 15:18:
>> On 9 May 2012 14:16, Vitja Makarov wrote:
>>> from cython cimport typeof
>>>
>>> def foo(float[::1] a):
>>>    b = a
>>>    #del b
>>>    print typeof(b)
>>>    print typeof(a)
>>>
>>>
>>> In this example `b` is inferred as 'Python object' and not
>>> `float[::1]`, is that correct?
>>>
>> That's the current behaviour, but it would be better if it inferred a
>> memoryview slice instead.
>
> +1

+1. This looks like it would break inference of extension classes as well.

https://github.com/vitek/cython/commit/f5acf44be0f647bdcbb5a23c8bfbceff48f4414e#L0R336

could be changed to check if it's already a py_object_type (or memory
view) as a quick fix, but it's not as pure as adding the constraints
"can be del'ed" to the type inference engine.

- Robert