syntax_data: {"ast_node_type":"other","tokens":[{"end":82,"kind":"keyword","start":0,"text":"debug_assert_eq!(tcx.def_kind(impl_def_id),"}]}
source_snippet:     debug_assert_eq!(tcx.def_kind(impl_def_id), DefKind::Impl { of_trait: true });
context_before: fn impl_self_is_guaranteed_unsized<'tcx>(tcx: TyCtxt<'tcx>, impl_def_id: DefId) -> bool {