The curly bracket separator is assigned to “curl”, but then the previous “curly” variable is tested:

https://hg.python.org/cpython/annotate/3.5/Tools/clinic/clinic.py#l202

name, curl, trailing = trailing.partition('}')
if not curly or name not in kwargs:
    ...

I presume the fix is to assign to “curly”, but I haven’t had a chance to figure out how to test it yet.

Yeah, change "curl" to "curly".  If you commit the fix without a test case I'd forgive you.  Or I can do it if that makes you nervous.

Go ahead.

New changeset aec2eae8933e by Martin Panter in branch '3.5':
Issue #26316: Fix variable name typo in Argument Clinic
https://hg.python.org/cpython/rev/aec2eae8933e

New changeset 6c122e4e1cb2 by Martin Panter in branch 'default':
Issue #26316: Merge Arg Clinic fix from 3.5
https://hg.python.org/cpython/rev/6c122e4e1cb2

I did look into testing, but I gave up. :) The test file doesn’t even import. I got the following error (without exception or traceback), cause by the line that reads “c = clinic.Clinic(language='C')”:

$ (cd Tools/clinic/ && ../../python clinic_test.py)
Error:
Destination does not exist: 'file'
[Exit 255]