The current code which handles anonymous functions within strip_dots (in aes_calculated.r) is broken for anonymous functions. With pairlists, it tries to lapply each member of the pairlist to itself lapply(expr, expr) which I think will always result in an error.
Minimal reproducible example:
ggplot2:::strip_dots(quote(function(x) x))
I'm about to submit a pull request which fixes this issue.