syntax_data: {"ast_node_type":"other","tokens":[{"end":52,"kind":"keyword","start":0,"text":"hidden_ty:"}]}
source_snippet:         hidden_ty: <Self::Interner as Interner>::Ty,
context_before:         opaque_type_key: ty::OpaqueTypeKey<Self::Interner>,
context_after:         span: <Self::Interner as Interner>::Span,