There should also be a mention of this in the release notes (especially if the default behavior winds up changing).
It took me a few tries to understand why there's a leading whitespace here. I'd prefer this to be a trailing whitespace on the previous line as in other cases unless there's some reason we need all the trailing quotes to line up vertically.
We should document explicitly that this is the default (or document AsIs as the default if we go that route for now).
While we want to get here eventually, I think it might make sense to have the default be AsIs until there's clear agreement that we want the default traversal mode in AST matchers to be this way. Basically, clang-query's default mode should be the same as the C++ AST matcher default mode.
Can you also add a test for set traversal ThisShouldNotWork or something along those lines?
It looks like none of the comments in the review have not been addressed yet. Are you planning to make those changes? (Some may no longer be necessary because we've made a decision that moots the comment.)