{"ast_node_type":"other","tokens":[{"end":84,"kind":"keyword","start":0,"text":"//"}]}
    // More generally, if MIR is a lone `unreachable`, there is nothing to optimize.
    // predicates, it will shrink the MIR to a single `unreachable` terminator.
    if let TerminatorKind::Unreachable = body.basic_blocks[START_BLOCK].terminator().kind