Compiler crash in AnalyseExpressionsTransform

[vijairaj]

I am using Cython 0.25.2 on Windows 7 (x64) and found Cython to be crashing when compiling a .py file.

Reduced test to reproduce the issue

class Number: zero = 0

def main():
    m1 = 1 + max(1, Number.zero)
    m2 = m1
    print m2

main()

Changes that makes the error disappear

• If I change Number.zero to a local variable or a constant
• If I change the order of parameters in max
• If I remove m2 = m1

Stack trace

Error compiling Cython file:
------------------------------------------------------------
...
class Number: zero = 0

def main():
^
------------------------------------------------------------

cyerr.py:3:0: Compiler crash in AnalyseExpressionsTransform

ModuleNode.body = StatListNode(cyerr.py:1:0)
StatListNode.stats[1] = DefNode(cyerr.py:3:0,
    is_cyfunction = True,
    modifiers = [...]/0,
    name = u'main',
    py_wrapper_required = True,
    reqd_kw_flags_cname = '0',
    used = True)

Compiler crash traceback from this point on:
  File "Cython\Compiler\Visitor.py", line 180, in Cython.Compiler.Visitor.TreeVisitor._visit (C:\projects\cython-wheels\Cython\Cython\Compiler\Visitor.c:5261)
    return handler_method(obj)
  File "c:\python27\lib\site-packages\Cython\Compiler\ParseTreeTransforms.py", line 2008, in visit_FuncDefNode
    node.local_scope.infer_types()
  File "c:\python27\lib\site-packages\Cython\Compiler\Symtab.py", line 887, in infer_types
    get_type_inferer().infer_types(self)
  File "c:\python27\lib\site-packages\Cython\Compiler\TypeInference.py", line 454, in infer_types
    if not resolve_assignments(assignments):
  File "c:\python27\lib\site-packages\Cython\Compiler\TypeInference.py", line 419, in resolve_assignments
    infer_name_node_type(node)
  File "c:\python27\lib\site-packages\Cython\Compiler\TypeInference.py", line 401, in infer_name_node_type
    types, entry.might_overflow, entry.pos, scope)
  File "c:\python27\lib\site-packages\Cython\Compiler\TypeInference.py", line 523, in safe_spanning_type
    result_type = simply_type(reduce(find_spanning_type, types), pos)
  File "c:\python27\lib\site-packages\Cython\Compiler\TypeInference.py", line 509, in simply_type
    if result_type.is_reference:
AttributeError: 'NoneType' object has no attribute 'is_reference'

[scoder]

Thank you for this excellent bug report.