syntax_data: {"ast_node_type":"impl","tokens":[{"end":52,"kind":"keyword","start":0,"text":"normalize:"}]}
source_snippet:         normalize: impl FnMut(Ty<'tcx>) -> Ty<'tcx>,
context_before:         tcx: TyCtxt<'tcx>,
context_after:     ) -> Result<Ty<'tcx>, Ty<'tcx>> {