syntax_data: {"ast_node_type":"other","tokens":[{"end":68,"kind":"keyword","start":0,"text":"self.local_decls[local].mutability"}]}
source_snippet:                     self.local_decls[local].mutability = mutability;
context_before:                 } => {
context_after:                     self.local_decls[local].source_info.scope = self.source_scope;