How to debug TypeError: required field "lineno" missing from expr?

[Terry Reedy]

On 6/29/2015 3:08 AM, Laura Creighton wrote:
> In a message of Mon, 29 Jun 2015 02:14:43 +0100, Mark Lawrence writes:
>> Purely as an exercise I've been converting Grant Jenks' pypatt[1] from
>> 2.7 to 3.4.  I've managed to sort out most of the required changes by
>> checking on what I can see with an AST pretty printer[2].  So it's
>> rather frustrating to have the compile stage throw the error given in
>> the subject line.
>
> Are you trying to use ast.copy_location recursively somewhere?
> http://bugs.python.org/issue3530   Maybe you have found something else
> that doesn't work recursively?

I do not understand the closing of this issue given that a) the failing 
part of the code is copied from the doc (3.4 has the same in the 
docstring) and b) that there is no recursion for a single node ast, 
which the example should be.

The error message comes from
F:\Python\dev\34\Python\Python-ast.c: 3752:
PyErr_SetString(PyExc_TypeError, "required field \"lineno\" missing from 
stmt");

-- 
Terry Jan Reedy