 }
 
 // https://github.com/apple/swift/blob/master/docs/SIL.rst#basic-blocks
-public class Block {
+public class Block: Equatable {
     public let identifier: String
     public let arguments: [Argument]
     public let operatorDefs: [OperatorDef]

    }
}

public enum InstructionDef {
    case `operator`(OperatorDef)
    case terminator(TerminatorDef)
}

}

// https://github.com/apple/swift/blob/master/docs/SIL.rst#debug-information
public struct Loc: Equatable {
    public let path: String
    public let line: Int
    public let column: Int
