LGTM
https://codereview.appspot.com/559450053/diff/547570044/lily/accidental-placement.cc File lily/accidental-placement.cc (right): https://codereview.appspot.com/559450053/diff/547570044/lily/accidental-placement.cc#newcode62 lily/accidental-placement.cc:62: scm_from_long (stagger ? context_hash : 1)); Are you actually trying clang-format? There's one space too much :-) https://codereview.appspot.com/559450053/
