syntax_data: {"ast_node_type":"other","tokens":[{"end":102,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // FIXME(type_alias_impl_trait): can we require mentioning nested type aliases explicitly?
context_before:             // Skips type aliases, as they are meant to be transparent.
context_after:             ty::Alias(ty::Free, alias_ty) if let Some(def_id) = alias_ty.def_id.as_local() => {