Error compiling Cython file:
------------------------------------------------------------
...
cdef extern from *:
    const int A = 0
    const int B = A + 1
                   ^
------------------------------------------------------------

my.pyx:3:20: Compiler crash in OptimizeBuiltinCalls

ModuleNode.body = StatListNode(my.pyx:1:5)
StatListNode.stats[0] = CDefExternNode(my.pyx:1:5)
CDefExternNode.body = StatListNode(my.pyx:2:4)
StatListNode.stats[1] = SingleAssignmentNode(my.pyx:3:4)
SingleAssignmentNode.rhs = AddNode(my.pyx:3:20,
    infix = True,
    operator = '+',
    result_is_used = True,
    use_managed_ref = True)

Compiler crash traceback from this point on:
  File "c:\python39\lib\site-packages\Cython\Compiler\Visitor.py", line 180, in _visit
    return handler_method(obj)
  File "c:\python39\lib\site-packages\Cython\Compiler\Visitor.py", line 531, in visit_BinopNode
    return self._visit_binop_node(node)
  File "c:\python39\lib\site-packages\Cython\Compiler\Visitor.py", line 545, in _visit_binop_node
    if obj_type.is_builtin_type:
AttributeError: 'NoneType' object has no attribute 'is_builtin_type'