syntax_data: {"ast_node_type":"variable","tokens":[{"end":29,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let tcx = self.tcx();
context_before:     fn add_wf_preds_for_projection_args(&mut self, args: GenericArgsRef<'tcx>) {
context_after:         let cause = self.cause(ObligationCauseCode::WellFormed(None));