{"ast_node_type":"other","tokens":[{"end":72,"kind":"keyword","start":0,"text":"//"}]}
        // so treat this as if the user wrote e.g. `const A: _ = expr;`.
        // The user intended that the type be inferred,
        P(Ty { kind: TyKind::Infer, span, id: ast::DUMMY_NODE_ID, tokens: None })