test case for ticket #600: scope of iterable in genexprs

tests/bugs.txt

@@ -18,6 +18,7 @@ closure_inside_cdef_T554
 ipow_crash_T562
 pure_mode_cmethod_inheritance_T583
 list_comp_in_closure_T598
+genexpr_iterable_lookup_T600
 
 # CPython regression tests that don't current work:
 pyregr.test_threadsignals

tests/run/genexpr_iterable_lookup_T600.pyx

+
+cimport cython
+
+@cython.test_assert_path_exists('//ComprehensionNode')
+@cython.test_fail_if_path_exists('//SimpleCallNode')
+def list_genexpr_iterable_lookup():
+    """
+    >>> x = (0,1,2,3,4,5)
+    >>> [ x*2 for x in x if x % 2 == 0 ]  # leaks in Py2 but finds the right 'x'
+    [0, 4, 8]
+
+    >>> list_genexpr_iterable_lookup()
+    [0, 4, 8]
+    """
+    x = (0,1,2,3,4,5)
+    result = list( x*2 for x in x if x % 2 == 0 )
+    assert x == (0,1,2,3,4,5)
+    return result