syntax_data: {"ast_node_type":"function","tokens":[{"end":99,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn expand_opaque_ty(&mut self, def_id: DefId, args: GenericArgsRef<'tcx>) -> Option<Ty<'tcx>> {
context_before: impl<'tcx> OpaqueTypeExpander<'tcx> {
context_after:         if self.found_any_recursion {