Proper Identifier Tracking about jinja

[mitsuhiko]

This is finally done.

[mitsuhiko]

How do you know you are affected by this issue? You get something along the lines of "Unbound variable l_SOMETHING" found.

[jab]

From #pocoo just now:

magicbronson: hey mitsuhiko et al., trying to render a Jinja template in a Flask app and getting a very mysterious message: "global name 'l_config' is not defined"
magicbronson: l_config appears nowhere in my code or libraries'
mitsuhiko: magicbronson: that's the scoping bug that i will fix over this summer 
mitsuhiko: {% macro foo() %}{{ config }}{% for config in something_else %}{{config}}{% endfor %}{% endmacro %}
mitsuhiko: something like this triggers the bug currently
mitsuhiko: magicbronson: rename the variable inside of the macro to something else
mitsuhiko: {% set cfg = config %}
mitsuhiko: outside the macro
mitsuhiko: or something

Armin's suggestion worked around the issue.