syntax_data: {"ast_node_type":"other","tokens":[{"end":70,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                             // No matching transitions in `dst`. Fail.
context_before:                             (None, _) => None,
context_after:                             (Some(_), None) => Some(Answer::No(Reason::DstIsBitIncompatible)),