syntax_data: {"ast_node_type":"other","tokens":[{"end":75,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // This variable isn't mutated but has a name, so has to be
context_before:             let ref_for_guard = self.local_decls.push(LocalDecl::<'tcx> {
context_after:                 // immutable to avoid the unused mut lint.