syntax_data: {"ast_node_type":"other","tokens":[{"end":68,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// [dev-guide]: https://rustc-dev-guide.rust-lang.org/thir.html
context_before:     ///
context_after:     pub(crate) fn mirror_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) -> ExprId {