KtOperationReferenceExpression(54,56): '+='
  KaCallResolutionSuccess:
    call = KaSimpleFunctionCall:
      contextArgumentMapping = {}
      contextArguments = []
      dispatchReceiver = null
      extensionReceiver = KaExplicitReceiverValue:
        expression = l
        isSafeNavigation = false
        type = kotlin.collections.MutableList<kotlin.Int>
      signature = KaFunctionSignature:
        receiverType = kotlin.collections.MutableCollection<in kotlin.Int>
        returnType = kotlin.Unit
        symbol = kotlin/collections/plusAssign(<extension receiver>: kotlin.collections.MutableCollection<in T>, element: T): kotlin.Unit
        valueParameters = [
          KaVariableSignature:
            name = element
            receiverType = null
            returnType = kotlin.Int
            symbol = element: T
            contextParameters = []
            callableId = null
        ]
        contextParameters = []
        callableId = kotlin/collections/plusAssign
      typeArgumentsMapping = {
        T -> (kotlin.Int)
      }
      valueArgumentMapping = {
        1 -> (KaVariableSignature:
          name = element
          receiverType = null
          returnType = kotlin.Int
          symbol = element: T
          contextParameters = []
          callableId = null)
      }