[Pyrex] Bug in CoerceFromPyTypeNode in 0.9.5

[Peter Johnson]

I've run into a bug in 0.9.5 in ExprNodes.py line 2936:

   File "/usr/local/lib/python2.4/site-packages/Pyrex/Compiler/ExprNodes.py", 
line 402, in generate_evaluation_code
     self.generate_result_code(code)
   File "/usr/local/lib/python2.4/site-packages/Pyrex/Compiler/ExprNodes.py", 
line 2936, in generate_result_code
     rhs = typecast(rhs, self.type, c_long_type)
NameError: global name 'c_long_type' is not defined

This is a bug (c_long_type needs to be qualified), but changing this to use 
PyrexTypes.c_long_type doesn't get me much further:

   File "/usr/local/lib/python2.4/site-packages/Pyrex/Compiler/ExprNodes.py", 
line 402, in generate_evaluation_code
     self.generate_result_code(code)
   File "/usr/local/lib/python2.4/site-packages/Pyrex/Compiler/ExprNodes.py", 
line 2936, in generate_result_code
     rhs = typecast(rhs, self.type, PyrexTypes.c_long_type)
   File "/usr/local/lib/python2.4/site-packages/Pyrex/Compiler/PyrexTypes.py", 
line 821, in typecast
     if to_type is from_type or \
AttributeError: 'str' object has no attribute 'is_pyobject'

This is because rhs is assigned to a string right before the typecast call in 
ExprNodes.py:

         rhs = "%s(%s)" % (function, operand)
         if self.type.is_enum:
             rhs = typecast(rhs, self.type, PyrexTypes.c_long_type)

and the typecast code in PyrexTypes.py is:

def typecast(to_type, from_type, expr_code):
     if to_type is from_type or \
         (not to_type.is_pyobject and assignable_from(to_type, from_type)):
             return expr_code
     else:
         #print "typecast: to", to_type, "from", from_type ###
         return to_type.cast_code(expr_code)

Neither of these code paths handle to_type being a string.  I suspect the bug 
is in the ExprNodes.py function, but I'm not sure what the correct fix is 
supposed to be.

I'll work on getting a small testcase together for this.

Thanks,
Peter