KtOperationReferenceExpression(159,161): '+='
  KaCallResolutionSuccess:
    call = KaSimpleFunctionCall:
      contextArgumentMapping = {}
      contextArguments = []
      dispatchReceiver = KaExplicitReceiverValue:
        expression = withOperator
        isSafeNavigation = false
        type = test.WithOperator
      extensionReceiver = null
      signature = KaFunctionSignature:
        receiverType = null
        returnType = kotlin.Unit
        symbol = test/WithOperator.plusAssign(<dispatch receiver>: test.WithOperator, f: test.Foo): kotlin.Unit
        valueParameters = [
          KaVariableSignature:
            name = f
            receiverType = null
            returnType = test.Foo
            symbol = f: test.Foo
            contextParameters = []
            callableId = null
        ]
        contextParameters = []
        callableId = test/WithOperator.plusAssign
      typeArgumentsMapping = {}
      valueArgumentMapping = {
        foo -> (KaVariableSignature:
          name = f
          receiverType = null
          returnType = test.Foo
          symbol = f: test.Foo
          contextParameters = []
          callableId = null)
      }