syntax_data: {"ast_node_type":"variable","tokens":[{"end":91,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                     let a_dst = a_transitions.ref_transitions.get(ref_transition).copied();
context_before:                 .map(|ref_transition| {
context_after:                     let b_dst = b_transitions.ref_transitions.get(ref_transition).copied();