%debug magic doesn't capture the locals

[impact27]

To reproduce:
1 - create a file test.ipy:

def fun():
    res = 1
    %debug print(res)
fun()

2 - run with ipython test.ipy
3 - After pressing continue on the pdb promt, I get:
NameError: name 'res' is not defined

This is in contrast with the following code, which works:

def fun():
    res = 1
    %timeit print(res)
fun()

The difference seems to be that the timeit magic is decorated with @needs_local_scope