syntax_data: {"ast_node_type":"variable","tokens":[{"end":77,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let opt_ty = self.args.get(p.index() as usize).map(|arg| arg.kind());
context_before:         // Look up the type in the args. It really should be in there.
context_after:         let ty = match opt_ty {