Fix all the loop bugs

[robertwb]

def test_loop(N):
    cdef int i
    for i in range(N):
        print i
        i = 5
    return i

Gives

>>> loop.test_loop(3)
0
5
>>> loop.test_loop(10)
0
6
6
...

where the later is an infinite loop. What I think we should do is have a shadow loop variable in the C for loop, and assign it to the target loop variable at the top of the loop.

This would also independently solve http://trac.cython.org/ticket/208 and http://trac.cython.org/ticket/196 without a performance penalty.

Migrated from http://trac.cython.org/ticket/243

[robertwb]

@dagss changed milestone from 0.10.1 to 0.11.1
commented

[robertwb]

@robertwb changed owner from somebody to robertwb
commented

Tests at

http://hg.cython.org/cython-unstable/rev/e19ddb8be01d

Fixes at

http://hg.cython.org/cython-unstable/rev/0c165f57146c
http://hg.cython.org/cython-unstable/rev/03ef058d7133

[robertwb]

@robertwb changed resolution to fixed
status from new to closed
commented

[robertwb]

@robertwb changed component from Code Generation to Python Semantics
commented

[robertwb]

@robertwb changed summary from

another for in range loop bug

to

Fix all the loop bugs
commented