syntax_data: {"ast_node_type":"other","tokens":[{"end":52,"kind":"keyword","start":0,"text":"assert!(self.let_source"}]}
source_snippet:         assert!(self.let_source != LetSource::None);
context_before:     fn check_let(&mut self, pat: &'p Pat<'tcx>, scrutinee: Option<ExprId>, span: Span) {
context_after:         let scrut = scrutinee.map(|id| &self.thir[id]);