syntax_data: {"ast_node_type":"variable","tokens":[{"end":27,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let arg_local =
context_before:                 SourceInfo::outermost(param.pat.as_ref().map_or(self.fn_span, |pat| pat.span));
context_after:                 self.local_decls.push(LocalDecl::with_source_info(param.ty, source_info));