syntax_data: {"ast_node_type":"other","tokens":[{"end":38,"kind":"keyword","start":0,"text":"ByRef::Yes(mutbl)"}]}
source_snippet:                 ByRef::Yes(mutbl) => {
context_before:                 ByRef::No => Rvalue::Use(self.consume_by_copy_or_move(binding.source)),
context_after:                     Rvalue::Ref(re_erased, util::ref_pat_borrow_kind(mutbl), binding.source)