Refactoring. Remove ResolutionCandidateStatus.

Use diagnostics directly.
Also TowerCandidate since now know only about applicability
and not about diagnostics itself.

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tower/KotlinToResolvedCallTransformer.kt

@@ -347,7 +347,7 @@ class KotlinToResolvedCallTransformer(
         val newContext = context.replaceBindingTrace(trackingTrace)
         val diagnosticReporter = DiagnosticReporterByTrackingStrategy(constantExpressionEvaluator, newContext, completedCall.kotlinCall.psiKotlinCall)
 
-        for (diagnostic in completedCall.resolutionStatus.diagnostics) {
+        for (diagnostic in completedCall.diagnostics) {
             trackingTrace.reported = false
             diagnostic.report(diagnosticReporter)
 
@@ -464,7 +464,7 @@ class NewResolvedCallImpl<D : CallableDescriptor>(
 ): NewAbstractResolvedCall<D>() {
     override val kotlinCall: KotlinCall get() = completedCall.kotlinCall
 
-    override fun getStatus(): ResolutionStatus = completedCall.resolutionStatus.resultingApplicability.toResolutionStatus()
+    override fun getStatus(): ResolutionStatus = completedCall.resultingApplicability.toResolutionStatus()
 
     override val argumentMappingByOriginal: Map<ValueParameterDescriptor, ResolvedCallArgument>
         get() = completedCall.argumentMappingByOriginal
@@ -496,7 +496,7 @@ class NewVariableAsFunctionResolvedCallImpl(
 ): VariableAsFunctionResolvedCall, ResolvedCall<FunctionDescriptor> by functionCall
 
 class StubOnlyResolvedCall<D : CallableDescriptor>(val candidate: SimpleKotlinResolutionCandidate): NewAbstractResolvedCall<D>() {
-    override fun getStatus() = candidate.status.resultingApplicability.toResolutionStatus()
+    override fun getStatus() = candidate.resultingApplicability.toResolutionStatus()
 
     override fun getCandidateDescriptor(): D = candidate.candidateDescriptor as D
     override fun getResultingDescriptor(): D = candidate.descriptorWithFreshTypes as D

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tower/NewResolutionOldInference.kt

@@ -29,7 +29,6 @@ import org.jetbrains.kotlin.psi.Call
 import org.jetbrains.kotlin.psi.KtReferenceExpression
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.TemporaryBindingTrace
-import org.jetbrains.kotlin.resolve.calls.model.KotlinCallKind
 import org.jetbrains.kotlin.resolve.calls.CallTransformer
 import org.jetbrains.kotlin.resolve.calls.CandidateResolver
 import org.jetbrains.kotlin.resolve.calls.callResolverUtil.isBinaryRemOperator
@@ -38,9 +37,7 @@ import org.jetbrains.kotlin.resolve.calls.callResolverUtil.isInfixCall
 import org.jetbrains.kotlin.resolve.calls.callUtil.createLookupLocation
 import org.jetbrains.kotlin.resolve.calls.context.*
 import org.jetbrains.kotlin.resolve.calls.inference.CoroutineInferenceSupport
-import org.jetbrains.kotlin.resolve.calls.model.MutableResolvedCall
-import org.jetbrains.kotlin.resolve.calls.model.ResolvedCallImpl
-import org.jetbrains.kotlin.resolve.calls.model.VariableAsFunctionResolvedCallImpl
+import org.jetbrains.kotlin.resolve.calls.model.*
 import org.jetbrains.kotlin.resolve.calls.results.OverloadResolutionResultsImpl
 import org.jetbrains.kotlin.resolve.calls.results.ResolutionResultsHandler
 import org.jetbrains.kotlin.resolve.calls.results.ResolutionStatus
@@ -176,7 +173,7 @@ class NewResolutionOldInference(
 
         // Temporary hack to resolve 'rem' as 'mod' if the first is do not present
         val emptyOrInapplicableCandidates = candidates.isEmpty() ||
-                                            candidates.all { it.candidateStatus.resultingApplicability.isInapplicable }
+                                            candidates.all { it.resultingApplicability.isInapplicable }
         if (isBinaryRemOperator && shouldUseOperatorRem && emptyOrInapplicableCandidates) {
             val deprecatedName = OperatorConventions.REM_TO_MOD_OPERATION_NAMES[name]
             val processorForDeprecatedName = kind.createTowerProcessor(this, deprecatedName!!, tracing, scopeTower, detailedReceiver, context)
@@ -204,7 +201,7 @@ class NewResolutionOldInference(
             val resolvedCall = ResolvedCallImpl.create(candidate, candidateTrace, tracing, basicCallContext.dataFlowInfoForArguments)
 
             if (candidate.descriptor.isHiddenInResolution(languageVersionSettings, basicCallContext.isSuperCall)) {
-                return@map MyCandidate(ResolutionCandidateStatus(listOf(HiddenDescriptor)), resolvedCall)
+                return@map MyCandidate(listOf(HiddenDescriptor), resolvedCall)
             }
 
             val callCandidateResolutionContext = CallCandidateResolutionContext.create(
@@ -214,16 +211,16 @@ class NewResolutionOldInference(
             candidateResolver.performResolutionForCandidateCall(callCandidateResolutionContext, basicCallContext.checkArguments) // todo
 
             val diagnostics = listOfNotNull(createPreviousResolveError(resolvedCall.status))
-            MyCandidate(ResolutionCandidateStatus(diagnostics), resolvedCall)
+            MyCandidate(diagnostics, resolvedCall)
         }
         if (basicCallContext.collectAllCandidates) {
             val allCandidates = towerResolver.runWithEmptyTowerData(KnownResultProcessor(resolvedCandidates),
-                                                  TowerResolver.AllCandidatesCollector { it.candidateStatus }, useOrder = false)
+                                                  TowerResolver.AllCandidatesCollector(), useOrder = false)
             return allCandidatesResult(allCandidates)
         }
 
         val processedCandidates = towerResolver.runWithEmptyTowerData(KnownResultProcessor(resolvedCandidates),
-                                                    TowerResolver.SuccessfulResultCollector { it.candidateStatus }, useOrder = true)
+                                                    TowerResolver.SuccessfulResultCollector(), useOrder = true)
 
         return convertToOverloadResults(processedCandidates, tracing, basicCallContext, languageVersionSettings)
     }
@@ -240,7 +237,7 @@ class NewResolutionOldInference(
             languageVersionSettings: LanguageVersionSettings
     ): OverloadResolutionResultsImpl<D> {
         val resolvedCalls = candidates.map {
-            val (status, resolvedCall) = it
+            val (diagnostics, resolvedCall) = it
             if (resolvedCall is VariableAsFunctionResolvedCallImpl) {
                 // todo hacks
                 tracing.bindReference(resolvedCall.variableCall.trace, resolvedCall.variableCall)
@@ -256,7 +253,7 @@ class NewResolutionOldInference(
             }
 
             if (resolvedCall.status.possibleTransformToSuccess()) {
-                for (error in status.diagnostics) {
+                for (error in diagnostics) {
                     when (error) {
                         is UnsupportedInnerClassCall -> resolvedCall.trace.report(Errors.UNSUPPORTED.on(resolvedCall.call.callElement, error.message))
                         is NestedClassViaInstanceReference -> tracing.nestedClassAccessViaInstanceReference(resolvedCall.trace, error.classDescriptor, resolvedCall.explicitReceiverKind)
@@ -317,13 +314,11 @@ class NewResolutionOldInference(
     }
 
     internal data class MyCandidate(
-            val candidateStatus: ResolutionCandidateStatus,
+            val diagnostics: List<KotlinCallDiagnostic>,
             val resolvedCall: MutableResolvedCall<*>
     ) : Candidate {
-        override val isSuccessful: Boolean
-            get() = candidateStatus.resultingApplicability.isSuccess
-        override val status: ResolutionCandidateStatus
-            get() = candidateStatus
+        override val resultingApplicability: ResolutionCandidateApplicability = getResultApplicability(diagnostics)
+        override val isSuccessful get() = resultingApplicability.isSuccess
     }
 
     private inner class CandidateFactoryImpl(
@@ -358,12 +353,12 @@ class NewResolutionOldInference(
                 if (parameterIsDynamic != argumentIsDynamic ||
                     (parameterIsDynamic && !towerCandidate.descriptor.hasDynamicExtensionAnnotation())
                 ) {
-                    return MyCandidate(ResolutionCandidateStatus(listOf(HiddenExtensionRelatedToDynamicTypes)), candidateCall)
+                    return MyCandidate(listOf(HiddenExtensionRelatedToDynamicTypes), candidateCall)
                 }
             }
 
             if (towerCandidate.descriptor.isHiddenInResolution(languageVersionSettings, basicCallContext.isSuperCall)) {
-                return MyCandidate(ResolutionCandidateStatus(listOf(HiddenDescriptor)), candidateCall)
+                return MyCandidate(listOf(HiddenDescriptor), candidateCall)
             }
 
             val callCandidateResolutionContext = CallCandidateResolutionContext.create(
@@ -375,7 +370,7 @@ class NewResolutionOldInference(
             val diagnostics = (towerCandidate.diagnostics +
                                checkInfixAndOperator(basicCallContext.call, towerCandidate.descriptor) +
                                createPreviousResolveError(candidateCall.status)).filterNotNull() // todo
-            return MyCandidate(ResolutionCandidateStatus(diagnostics), candidateCall)
+            return MyCandidate(diagnostics, candidateCall)
         }
 
         private fun checkInfixAndOperator(call: Call, descriptor: CallableDescriptor): List<ResolutionDiagnostic> {
@@ -403,11 +398,11 @@ class NewResolutionOldInference(
                     invoke.resolvedCall as MutableResolvedCall<FunctionDescriptor>,
                     variable.resolvedCall as MutableResolvedCall<VariableDescriptor>
             )
-            assert(variable.candidateStatus.resultingApplicability.isSuccess) {
+            assert(variable.resultingApplicability.isSuccess) {
                 "Variable call must be success: $variable"
             }
 
-            return MyCandidate(ResolutionCandidateStatus(variable.candidateStatus.diagnostics + invoke.candidateStatus.diagnostics), resolvedCallImpl)
+            return MyCandidate(variable.diagnostics + invoke.diagnostics, resolvedCallImpl)
         }
 
         override fun factoryForVariable(stripExplicitReceiver: Boolean): CandidateFactory<MyCandidate> {

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tower/PSICallResolver.kt

@@ -179,7 +179,7 @@ class PSICallResolver(
             1 -> {
                 val singleCandidate = result.single()
 
-                val isInapplicableReceiver = singleCandidate.currentStatus.resultingApplicability == ResolutionCandidateApplicability.INAPPLICABLE_WRONG_RECEIVER
+                val isInapplicableReceiver = singleCandidate.resultingApplicability == ResolutionCandidateApplicability.INAPPLICABLE_WRONG_RECEIVER
 
                 val resolvedCall = kotlinToResolvedCallTransformer.transformAndReport<D>(singleCandidate, context, trace.takeUnless { isInapplicableReceiver })
 
@@ -211,12 +211,12 @@ class PSICallResolver(
     private fun Collection<ResolvedKotlinCall>.areAllCompletedAndFailed() =
             all {
                 it is ResolvedKotlinCall.CompletedResolvedKotlinCall &&
-                !it.completedCall.resolutionStatus.resultingApplicability.isSuccess
+                !it.completedCall.resultingApplicability.isSuccess
             }
 
     private fun Collection<ResolvedKotlinCall>.areAllCompletedAndInapplicable() =
             all {
-                val applicability = it.currentStatus.resultingApplicability
+                val applicability = it.resultingApplicability
                 applicability == ResolutionCandidateApplicability.INAPPLICABLE ||
                 applicability == ResolutionCandidateApplicability.INAPPLICABLE_WRONG_RECEIVER ||
                 applicability == ResolutionCandidateApplicability.HIDDEN

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/KotlinCallResolver.kt

@@ -82,7 +82,7 @@ class KotlinCallResolver(
             )
         }
         val candidates = towerResolver.runWithEmptyTowerData(KnownResultProcessor(resolutionCandidates),
-                                                             TowerResolver.SuccessfulResultCollector { it.status },
+                                                             TowerResolver.SuccessfulResultCollector(),
                                                              useOrder = true)
         return choseMostSpecific(resolutionCallbacks, expectedType, candidates)
     }

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/AdditionalDiagnosticReporter.kt

@@ -42,7 +42,7 @@ class AdditionalDiagnosticReporter {
     }
 
     private fun reportSmartCastOnReceiver(
-            candidate: KotlinResolutionCandidate,
+            candidate: SimpleKotlinResolutionCandidate,
             receiver: SimpleKotlinCallArgument?,
             parameter: ReceiverParameterDescriptor?
     ): SmartCastDiagnostic? {
@@ -53,11 +53,11 @@ class AdditionalDiagnosticReporter {
 
         // todo may be we have smart cast to Int?
         return smartCastDiagnostic.takeIf {
-            candidate.status.diagnostics.filterIsInstance<UnsafeCallError>().none {
+            candidate.getCandidateDiagnostics().filterIsInstance<UnsafeCallError>().none {
                 it.receiver == receiver
             }
             &&
-            candidate.status.diagnostics.filterIsInstance<UnstableSmartCast>().none {
+            candidate.getCandidateDiagnostics().filterIsInstance<UnstableSmartCast>().none {
                 it.argument == receiver
             }
         }
@@ -72,7 +72,7 @@ class AdditionalDiagnosticReporter {
                     for (argument in candidate.argumentMappingByOriginal[parameter.original]?.arguments ?: continue) {
                         val smartCastDiagnostic = createSmartCastDiagnostic(argument, argument.getExpectedType(parameter)) ?: continue
 
-                        val thereIsUnstableSmartCastError = candidate.status.diagnostics.filterIsInstance<UnstableSmartCast>().any {
+                        val thereIsUnstableSmartCastError = candidate.getCandidateDiagnostics().filterIsInstance<UnstableSmartCast>().any {
                             it.argument == argument
                         }
 

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/CallableReferenceResolution.kt

@@ -68,9 +68,10 @@ class CallableReferenceCandidate(
         val explicitReceiverKind: ExplicitReceiverKind,
         val reflectionCandidateType: UnwrappedType,
         val numDefaults: Int,
-        override val status: ResolutionCandidateStatus
+        val diagnostics: List<KotlinCallDiagnostic>
 ) : Candidate {
-    override val isSuccessful get() = status.resultingApplicability.isSuccess
+    override val resultingApplicability = getResultApplicability(diagnostics)
+    override val isSuccessful get() = resultingApplicability.isSuccess
 }
 
 /**
@@ -184,9 +185,9 @@ class CallableReferencesCandidateFactory(
         }
 
         if (candidateDescriptor !is CallableMemberDescriptor) {
-            val status = ResolutionCandidateStatus(listOf(NotCallableMemberReference(argument, candidateDescriptor)))
             return CallableReferenceCandidate(candidateDescriptor, dispatchCallableReceiver, extensionCallableReceiver,
-                                              explicitReceiverKind, reflectionCandidateType, defaults, status)
+                                              explicitReceiverKind, reflectionCandidateType, defaults,
+                                              listOf(NotCallableMemberReference(argument, candidateDescriptor)))
         }
 
         diagnostics.addAll(towerCandidate.diagnostics)
@@ -205,7 +206,7 @@ class CallableReferencesCandidateFactory(
         }
 
         return CallableReferenceCandidate(candidateDescriptor, dispatchCallableReceiver, extensionCallableReceiver,
-                                          explicitReceiverKind, reflectionCandidateType, defaults, ResolutionCandidateStatus(diagnostics))
+                                          explicitReceiverKind, reflectionCandidateType, defaults, diagnostics)
     }
 
     private fun getArgumentAndReturnTypeUseMappingByExpectedType(

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/KotlinCallCompleter.kt

@@ -27,7 +27,6 @@ import org.jetbrains.kotlin.resolve.calls.inference.model.NewTypeVariable
 import org.jetbrains.kotlin.resolve.calls.inference.returnTypeOrNothing
 import org.jetbrains.kotlin.resolve.calls.inference.substituteAndApproximateCapturedTypes
 import org.jetbrains.kotlin.resolve.calls.model.*
-import org.jetbrains.kotlin.resolve.calls.tower.ResolutionCandidateStatus
 import org.jetbrains.kotlin.types.TypeApproximator
 import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
 import org.jetbrains.kotlin.types.TypeUtils
@@ -104,9 +103,9 @@ class KotlinCallCompleter(
             resolutionCallbacks: KotlinResolutionCallbacks
     ): ResolvedKotlinCall.CompletedResolvedKotlinCall {
         val currentSubstitutor = c.buildResultingSubstitutor()
-        val completedCall = candidate.toCompletedCall(currentSubstitutor)
+        val completedCall = candidate.toCompletedCall(currentSubstitutor, isTopLevel = true)
         val competedCalls = c.innerCalls.map {
-            it.candidate.toCompletedCall(currentSubstitutor)
+            it.candidate.toCompletedCall(currentSubstitutor, isTopLevel = false)
         }
         for (postponedArgument in c.postponedArguments) {
             when (postponedArgument) {
@@ -125,17 +124,17 @@ class KotlinCallCompleter(
         return ResolvedKotlinCall.CompletedResolvedKotlinCall(completedCall, competedCalls, c.lambdaArguments)
     }
 
-    private fun KotlinResolutionCandidate.toCompletedCall(substitutor: NewTypeSubstitutor): CompletedKotlinCall {
+    private fun KotlinResolutionCandidate.toCompletedCall(substitutor: NewTypeSubstitutor, isTopLevel: Boolean): CompletedKotlinCall {
         if (this is VariableAsFunctionKotlinResolutionCandidate) {
-            val variable = resolvedVariable.toCompletedCall(substitutor)
-            val invoke = invokeCandidate.toCompletedCall(substitutor)
+            val variable = resolvedVariable.toCompletedCall(substitutor, isTopLevel = false)
+            val invoke = invokeCandidate.toCompletedCall(substitutor, isTopLevel)
 
             return CompletedKotlinCall.VariableAsFunction(kotlinCall, variable, invoke)
         }
-        return (this as SimpleKotlinResolutionCandidate).toCompletedCall(substitutor)
+        return (this as SimpleKotlinResolutionCandidate).toCompletedCall(substitutor, isTopLevel)
     }
 
-    private fun SimpleKotlinResolutionCandidate.toCompletedCall(substitutor: NewTypeSubstitutor): CompletedKotlinCall.Simple {
+    private fun SimpleKotlinResolutionCandidate.toCompletedCall(substitutor: NewTypeSubstitutor, isTopLevel: Boolean): CompletedKotlinCall.Simple {
         val containsCapturedTypes = descriptorWithFreshTypes.returnType?.contains { it is NewCapturedType } ?: false
         val resultingDescriptor = when {
             descriptorWithFreshTypes is FunctionDescriptor ||
@@ -152,15 +151,22 @@ class KotlinCallCompleter(
             TypeApproximator().approximateToSuperType(substituted, TypeApproximatorConfiguration.CapturedTypesApproximation) ?: substituted
         }
 
-        val status = computeStatus(this, resultingDescriptor)
-        return CompletedKotlinCall.Simple(kotlinCall, candidateDescriptor, resultingDescriptor, status, explicitReceiverKind,
+        val diagnostics = computeDiagnostics(this, resultingDescriptor, isTopLevel)
+        return CompletedKotlinCall.Simple(kotlinCall, candidateDescriptor, resultingDescriptor, diagnostics, explicitReceiverKind,
                                           dispatchReceiverArgument?.receiver, extensionReceiver?.receiver, typeArguments, argumentMappingByOriginal)
     }
 
-    private fun computeStatus(candidate: SimpleKotlinResolutionCandidate, resultingDescriptor: CallableDescriptor): ResolutionCandidateStatus {
-        val smartCasts = additionalDiagnosticReporter.createAdditionalDiagnostics(candidate, resultingDescriptor).takeIf { it.isNotEmpty() } ?:
-                         return candidate.status
-        return ResolutionCandidateStatus(candidate.status.diagnostics + smartCasts)
+    private fun computeDiagnostics(
+            candidate: SimpleKotlinResolutionCandidate,
+            resultingDescriptor: CallableDescriptor,
+            isTopLevel: Boolean
+    ): List<KotlinCallDiagnostic> {
+        var diagnostics = candidate.getCandidateDiagnostics()
+        if (isTopLevel) {
+            diagnostics += candidate.constraintSystem.diagnostics
+        }
+        diagnostics += additionalDiagnosticReporter.createAdditionalDiagnostics(candidate, resultingDescriptor)
+        return diagnostics
     }
 
     // true if we should complete this call

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/model/ResolutionCandidate.kt

@@ -25,10 +25,7 @@ import org.jetbrains.kotlin.resolve.calls.inference.NewConstraintSystem
 import org.jetbrains.kotlin.resolve.calls.inference.model.NewConstraintSystemImpl
 import org.jetbrains.kotlin.resolve.calls.inference.model.NewTypeVariable
 import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind
-import org.jetbrains.kotlin.resolve.calls.tower.Candidate
-import org.jetbrains.kotlin.resolve.calls.tower.ImplicitScopeTower
-import org.jetbrains.kotlin.resolve.calls.tower.ResolutionCandidateStatus
-import org.jetbrains.kotlin.resolve.calls.tower.isSuccess
+import org.jetbrains.kotlin.resolve.calls.tower.*
 import org.jetbrains.kotlin.types.TypeSubstitutor
 import java.util.*
 
@@ -49,8 +46,8 @@ class VariableAsFunctionKotlinResolutionCandidate(
         val invokeCandidate: SimpleKotlinResolutionCandidate
 ) : KotlinResolutionCandidate() {
     override val isSuccessful: Boolean get() = resolvedVariable.isSuccessful && invokeCandidate.isSuccessful
-    override val status: ResolutionCandidateStatus
-        get() = ResolutionCandidateStatus(resolvedVariable.status.diagnostics + invokeCandidate.status.diagnostics)
+    override val resultingApplicability: ResolutionCandidateApplicability
+        get() = maxOf(resolvedVariable.resultingApplicability, invokeCandidate.resultingApplicability)
 
     override val lastCall: SimpleKotlinResolutionCandidate get() = invokeCandidate
 }
@@ -65,15 +62,10 @@ sealed class AbstractSimpleKotlinResolutionCandidate(
             return !hasErrors
         }
 
-    private var _status: ResolutionCandidateStatus? = null
-
-    override val status: ResolutionCandidateStatus
+    override val resultingApplicability: ResolutionCandidateApplicability
         get() {
-            if (_status == null) {
-                process(stopOnFirstError = false)
-                _status = ResolutionCandidateStatus(diagnostics + constraintSystem.diagnostics)
-            }
-            return _status!!
+            process(stopOnFirstError = false)
+            return getResultApplicability(diagnostics + constraintSystem.diagnostics)
         }
 
     private val diagnostics = ArrayList<KotlinCallDiagnostic>()
@@ -100,6 +92,7 @@ sealed class AbstractSimpleKotlinResolutionCandidate(
         addDiagnostics(initialDiagnostics)
     }
 
+    fun getCandidateDiagnostics(): List<KotlinCallDiagnostic> = diagnostics
 
     abstract val resolutionSequence: List<ResolutionPart>
 }

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/model/ResolvedKotlinCall.kt

@@ -19,49 +19,50 @@ package org.jetbrains.kotlin.resolve.calls.model
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
 import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind
-import org.jetbrains.kotlin.resolve.calls.tower.ResolutionCandidateStatus
+import org.jetbrains.kotlin.resolve.calls.tower.ResolutionCandidateApplicability
+import org.jetbrains.kotlin.resolve.calls.tower.getResultApplicability
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValueWithSmartCastInfo
 import org.jetbrains.kotlin.types.UnwrappedType
 
 sealed class ResolvedKotlinCall {
-    abstract val currentStatus: ResolutionCandidateStatus
+    abstract val resultingApplicability: ResolutionCandidateApplicability
 
     class CompletedResolvedKotlinCall(
             val completedCall: CompletedKotlinCall,
             val allInnerCalls: Collection<CompletedKotlinCall>,
             val lambdaArguments: List<PostponedLambdaArgument>
     ): ResolvedKotlinCall() {
-        override val currentStatus get() = completedCall.resolutionStatus
+        override val resultingApplicability get() = completedCall.resultingApplicability
     }
 
     class OnlyResolvedKotlinCall(val candidate: KotlinResolutionCandidate) : ResolvedKotlinCall() {
-        override val currentStatus get() = candidate.status
+        override val resultingApplicability get() = candidate.resultingApplicability
     }
 }
 
 sealed class CompletedKotlinCall {
-    abstract val resolutionStatus: ResolutionCandidateStatus
+    abstract val resultingApplicability: ResolutionCandidateApplicability
 
     class Simple(
             val kotlinCall: KotlinCall,
             val candidateDescriptor: CallableDescriptor,
             val resultingDescriptor: CallableDescriptor,
-            override val resolutionStatus: ResolutionCandidateStatus,
+            val diagnostics: List<KotlinCallDiagnostic>,
             val explicitReceiverKind: ExplicitReceiverKind,
             val dispatchReceiver: ReceiverValueWithSmartCastInfo?,
             val extensionReceiver: ReceiverValueWithSmartCastInfo?,
             val typeArguments: List<UnwrappedType>,
             val argumentMappingByOriginal: Map<ValueParameterDescriptor, ResolvedCallArgument>
-    ): CompletedKotlinCall()
+    ): CompletedKotlinCall() {
+        override val resultingApplicability = getResultApplicability(diagnostics)
+    }
 
     class VariableAsFunction(
             val kotlinCall: KotlinCall,
             val variableCall: Simple,
             val invokeCall: Simple
     ): CompletedKotlinCall() {
-
-        override val resolutionStatus: ResolutionCandidateStatus =
-                ResolutionCandidateStatus(variableCall.resolutionStatus.diagnostics + invokeCall.resolutionStatus.diagnostics)
+        override val resultingApplicability get() = maxOf(variableCall.resultingApplicability, invokeCall.resultingApplicability)
     }
 }
 

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/tower/ImplicitScopeTower.kt

@@ -21,8 +21,8 @@ import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithVisibility
 import org.jetbrains.kotlin.incremental.components.LookupLocation
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.resolve.calls.model.KotlinCallDiagnostic
 import org.jetbrains.kotlin.resolve.calls.model.DiagnosticReporter
+import org.jetbrains.kotlin.resolve.calls.model.KotlinCallDiagnostic
 import org.jetbrains.kotlin.resolve.calls.tower.ResolutionCandidateApplicability.*
 import org.jetbrains.kotlin.resolve.scopes.LexicalScope
 import org.jetbrains.kotlin.resolve.scopes.MemberScope
@@ -60,10 +60,8 @@ interface CandidateWithBoundDispatchReceiver {
     val dispatchReceiver: ReceiverValueWithSmartCastInfo?
 }
 
-data class ResolutionCandidateStatus(val diagnostics: List<KotlinCallDiagnostic>) {
-    val resultingApplicability: ResolutionCandidateApplicability = diagnostics.asSequence().map { it.candidateApplicability }.max()
-                                                                   ?: RESOLVED
-}
+fun getResultApplicability(diagnostics: List<KotlinCallDiagnostic>) = diagnostics.maxBy { it.candidateApplicability }?.candidateApplicability
+                                                                      ?: RESOLVED
 
 enum class ResolutionCandidateApplicability {
     RESOLVED, // call success or has uncompleted inference or in other words possible successful candidate

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/tower/TowerResolver.kt

@@ -28,7 +28,7 @@ interface Candidate {
     // this operation should be very fast
     val isSuccessful: Boolean
 
-    val status: ResolutionCandidateStatus
+    val resultingApplicability: ResolutionCandidateApplicability
 }
 
 interface CandidateFactory<out C: Candidate> {
@@ -75,13 +75,13 @@ class TowerResolver {
             scopeTower: ImplicitScopeTower,
             processor: ScopeTowerProcessor<C>,
             useOrder: Boolean
-    ): Collection<C> = scopeTower.run(processor, SuccessfulResultCollector { it.status }, useOrder)
+    ): Collection<C> = scopeTower.run(processor, SuccessfulResultCollector(), useOrder)
 
     fun <C: Candidate> collectAllCandidates(
             scopeTower: ImplicitScopeTower,
             processor: ScopeTowerProcessor<C>
     ): Collection<C>
-            = scopeTower.run(processor, AllCandidatesCollector { it.status }, false)
+            = scopeTower.run(processor, AllCandidatesCollector(), false)
 
     private fun ImplicitScopeTower.createNonLocalLevels(): List<ScopeTowerLevel> {
         val result = ArrayList<ScopeTowerLevel>()
@@ -100,7 +100,7 @@ class TowerResolver {
         return result
     }
 
-    private fun <C> ImplicitScopeTower.run(
+    private fun <C : Candidate> ImplicitScopeTower.run(
             processor: ScopeTowerProcessor<C>,
             resultCollector: ResultCollector<C>,
             useOrder: Boolean
@@ -173,13 +173,13 @@ class TowerResolver {
         return resultCollector.getFinalCandidates()
     }
 
-    fun <C> runWithEmptyTowerData(
+    fun <C : Candidate> runWithEmptyTowerData(
             processor: ScopeTowerProcessor<C>,
             resultCollector: ResultCollector<C>,
             useOrder: Boolean
     ): Collection<C> = processTowerData(processor, resultCollector, useOrder, TowerData.Empty) ?: resultCollector.getFinalCandidates()
 
-    private fun <C> processTowerData(
+    private fun <C : Candidate> processTowerData(
             processor: ScopeTowerProcessor<C>,
             resultCollector: ResultCollector<C>,
             useOrder: Boolean,
@@ -203,14 +203,14 @@ class TowerResolver {
     }
 
 
-    abstract class ResultCollector<C>(protected val getStatus: (C) -> ResolutionCandidateStatus) {
+    abstract class ResultCollector<C : Candidate> {
         abstract fun getSuccessfulCandidates(): Collection<C>?
 
         abstract fun getFinalCandidates(): Collection<C>
 
         fun pushCandidates(candidates: Collection<C>) {
             val filteredCandidates = candidates.filter {
-                getStatus(it).resultingApplicability != ResolutionCandidateApplicability.HIDDEN
+                it.resultingApplicability != ResolutionCandidateApplicability.HIDDEN
             }
             if (filteredCandidates.isNotEmpty()) addCandidates(filteredCandidates)
         }
@@ -218,7 +218,7 @@ class TowerResolver {
         protected abstract fun addCandidates(candidates: Collection<C>)
     }
 
-    class AllCandidatesCollector<C>(getStatus: (C) -> ResolutionCandidateStatus): ResultCollector<C>(getStatus) {
+    class AllCandidatesCollector<C : Candidate>: ResultCollector<C>() {
         private val allCandidates = ArrayList<C>()
 
         override fun getSuccessfulCandidates(): Collection<C>? = null
@@ -230,7 +230,7 @@ class TowerResolver {
         }
     }
 
-    class SuccessfulResultCollector<C>(getStatus: (C) -> ResolutionCandidateStatus): ResultCollector<C>(getStatus) {
+    class SuccessfulResultCollector<C : Candidate>: ResultCollector<C>() {
         private var currentCandidates: Collection<C> = emptyList()
         private var currentLevel: ResolutionCandidateApplicability? = null
 
@@ -247,10 +247,10 @@ class TowerResolver {
         override fun getFinalCandidates() = getResolved() ?: getResolvedLowPriority() ?: getErrors() ?: emptyList()
 
         override fun addCandidates(candidates: Collection<C>) {
-            val minimalLevel = candidates.map { getStatus(it).resultingApplicability }.min()!!
+            val minimalLevel = candidates.map { it.resultingApplicability }.min()!!
             if (currentLevel == null || currentLevel!! > minimalLevel) {
                 currentLevel = minimalLevel
-                currentCandidates = candidates.filter { getStatus(it).resultingApplicability == minimalLevel }
+                currentCandidates = candidates.filter { it.resultingApplicability == minimalLevel }
             }
         }
     }