syntax_data: {"ast_node_type":"other","tokens":[{"end":59,"kind":"keyword","start":0,"text":"opaque_type_key:"}]}
source_snippet:         opaque_type_key: ty::OpaqueTypeKey<Self::Interner>,
context_before:         &self,
context_after:         hidden_ty: <Self::Interner as Interner>::Ty,