KtOperationReferenceExpression(195,197): '+='
  KaApplicableCallCandidate:
    candidate = KaCompoundVariableAccessCall:
      compoundOperation = KaCompoundAssignOperation:
        kind = PLUS_ASSIGN
        operand = foo
        operationCall = KaSimpleFunctionCall:
          contextArgumentMapping = {}
          contextArguments = []
          dispatchReceiver = KaExplicitReceiverValue:
            expression = variable
            isSafeNavigation = false
            type = test.WithOperator
          extensionReceiver = null
          signature = KaFunctionSignature:
            receiverType = null
            returnType = test.WithOperator
            symbol = test/WithOperator.plus(<dispatch receiver>: test.WithOperator, f: test.Foo): test.WithOperator
            valueParameters = [
              KaVariableSignature:
                name = f
                receiverType = null
                returnType = test.Foo
                symbol = f: test.Foo
                contextParameters = []
                callableId = null
            ]
            contextParameters = []
            callableId = test/WithOperator.plus
          typeArgumentsMapping = {}
          valueArgumentMapping = {
            variable -> (KaVariableSignature:
              name = f
              receiverType = null
              returnType = test.Foo
              symbol = f: test.Foo
              contextParameters = []
              callableId = null)
          }
      variableCall = KaSimpleVariableAccessCall:
        contextArguments = []
        dispatchReceiver = null
        extensionReceiver = null
        isContextSensitive = false
        kind = Read
        signature = KaVariableSignature:
          name = variable
          receiverType = null
          returnType = test.WithOperator
          symbol = var variable: test.WithOperator
          contextParameters = []
          callableId = null
        typeArgumentsMapping = {}
    isInBestCandidates = true