syntax_data: {"ast_node_type":"other","tokens":[{"end":26,"kind":"keyword","start":0,"text":"tcx:"}]}
source_snippet:         tcx: TyCtxt<'tcx>,
context_before:     struct UsedParamsNeedInstantiationVisitor<'tcx> {
context_after:         typing_env: ty::TypingEnv<'tcx>,