syntax_data: {"ast_node_type":"other","tokens":[{"end":38,"kind":"keyword","start":0,"text":"layout:"}]}
source_snippet:         layout: &'a TyAndLayout<'tcx>,
context_before:         cx: &'a LayoutCx<'tcx>,
context_after:     ) -> impl Iterator<Item = (Size, TyAndLayout<'tcx>)> {