[tmoertel]

In this case, however, I don't want to use something like `git add -p` to pick the sledgehammer's good effects from the bad. That there are bad effects means the original sledgehammer was wrong. I want to fix the sledgehammer.

Yes, I could accept the good effects and then create a new sledgehammer to attempt to fix the bad effects (without affecting any good effects or any original code that just happens to look like a bad effect), but it's easier and more reliable to just roll back all of the effects, fix the original sledgehammer (tweak the regex), and reapply it to the original clean slate.