KtInapplicableCallCandidateInfo:
  diagnostic = ERROR<INVISIBLE_REFERENCE: Symbol private final fun foo(): R|kotlin/Unit| is invisible>
  candidate = KtSimpleFunctionCall:
    isImplicitInvoke = false
    partiallyAppliedSymbol = KtPartiallyAppliedSymbol:
      dispatchReceiver = KtExplicitReceiverValue:
        expression = a
        isSafeNavigation = false
      extensionReceiver = null
      signature = KtFunctionLikeSignature:
        receiverType = null
        returnType = kotlin.Unit
        symbol = /A.foo(<dispatch receiver>: A): kotlin.Unit
        valueParameters = []
    argumentMapping = {}
  isInBestCandidates = true
