jashkenas/coffee-script — pull request #3111 by jwalton (2013-08-06 20:28:29+00:00)
Title: Issue #3092: Fix column numbers in sourcemaps to not be essentially random.

There was an embarrassing bug in the way column numbers were computed. :)

The results from http://sokra.github.io/source-map-visualization are not as perfect as they could be - there's definitely some fine tuning to be done in terms of what gets mapped to what - but the results are obviously *miles* better than they were.