syntax_data: {"ast_node_type":"other","tokens":[{"end":56,"kind":"keyword","start":0,"text":"impl<'tcx>"}]}
source_snippet:     impl<'tcx> Tree<Def<'tcx>, Region<'tcx>, Ty<'tcx>> {
context_after:         pub(crate) fn from_ty(ty: Ty<'tcx>, cx: LayoutCx<'tcx>) -> Result<Self, Err> {