syntax_data: {"ast_node_type":"variable","tokens":[{"end":66,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let cx = self.new_cx(refutability, None, scrut, pat.span);
context_before:     ) -> Result<(PatCtxt<'p, 'tcx>, UsefulnessReport<'p, 'tcx>), ErrorGuaranteed> {
context_after:         let pat = self.lower_pattern(&cx, pat)?;