         let rhsC = box as! PColumnBoxImpl<T>
         return self == rhsC
     }
-
-    // Ensure no one else can conform to PColumn other than PTypedColumn. This is to ensure
-    // equality behaves in a reasonable manner, due to having to work around Swift's
-    // existential type implementation.
-    var _doNotConformToPColumn: _PTypedColumnToken { _PTypedColumnToken() }
-
 }
 
 fileprivate protocol HasNumeric {

        op.build(for: self)
    }
}

/// A token type that has a package-private initializer to ensure that no other type other than PTypedColumn can confirm to PColumn
public struct _PTypedColumnToken {
    fileprivate init() {}
}


    // A "poor-man's" equality check (without breaking PColumn as an existential
    func _isEqual(to box: PColumnBox) -> Bool
}

fileprivate struct PColumnBoxImpl<T: ElementRequirements>: PColumnBox, Equatable {
