syntax_data: {"ast_node_type":"variable","tokens":[{"end":37,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                         let user_ty =
context_before:                         let user_provided_types = self.typeck_results.user_provided_types();
context_after:                             user_provided_types.get(fun.hir_id).copied().map(|mut u_ty| {