{"ast_node_type":"other","tokens":[{"end":82,"kind":"keyword","start":0,"text":"debug!(\"deduce_future_output_from_projection:"}]}
        debug!("deduce_future_output_from_projection: output_ty={:?}", output_ty);
        let output_ty = self.resolve_vars_if_possible(predicate.term);
        // This is a projection on a Fn trait so will always be a type.