[FIR] Extract ResolutionStageRunner component

That component is responsible to run all resolution stages on candidate
  and calculating resulting applicability.

This is needed for completion of `when` and `try` as function calls

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/FirCallResolver.kt

@@ -41,7 +41,8 @@ class FirCallResolver(
     private val scopes: List<FirScope>,
     private val localScopes: List<FirScope>,
     private val implicitReceiverStack: List<ImplicitReceiverValue>,
-    private val qualifiedResolver: FirQualifiedNameResolver
+    private val qualifiedResolver: FirQualifiedNameResolver,
+    private val resolutionStageRunner: ResolutionStageRunner
 ) : BodyResolveComponents by transformer {
 
     fun resolveCallAndSelectCandidate(functionCall: FirFunctionCall, expectedTypeRef: FirTypeRef?, file: FirFile): FirFunctionCall {
@@ -66,7 +67,7 @@ class FirCallResolver(
             file,
             transformer.container
         ) { it.resultType }
-        val resolver = CallResolver(returnTypeCalculator, inferenceComponents)
+        val resolver = CallResolver(returnTypeCalculator, inferenceComponents, resolutionStageRunner)
         resolver.callInfo = info
         resolver.scopes = (scopes + localScopes).asReversed()
 
@@ -156,7 +157,7 @@ class FirCallResolver(
             file,
             transformer.container
         ) { it.resultType }
-        val resolver = CallResolver(returnTypeCalculator, inferenceComponents)
+        val resolver = CallResolver(returnTypeCalculator, inferenceComponents, resolutionStageRunner)
         resolver.callInfo = info
         resolver.scopes = (scopes + localScopes).asReversed()
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CallResolver.kt

@@ -14,7 +14,11 @@ enum class TowerDataKind {
     TOWER_LEVEL
 }
 
-class CallResolver(val typeCalculator: ReturnTypeCalculator, val components: InferenceComponents) {
+class CallResolver(
+    val typeCalculator: ReturnTypeCalculator,
+    val components: InferenceComponents,
+    val resolutionStageRunner: ResolutionStageRunner
+) {
     var callInfo: CallInfo? = null
     var scopes: List<FirScope>? = null
 
@@ -51,7 +55,7 @@ class CallResolver(val typeCalculator: ReturnTypeCalculator, val components: Inf
         return group
     }
 
-    val collector by lazy { CandidateCollector(components) }
+    val collector by lazy { CandidateCollector(components, resolutionStageRunner) }
     lateinit var towerDataConsumer: TowerDataConsumer
     private lateinit var implicitReceiverValues: List<ImplicitReceiverValue>
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CandidateCollector.kt

@@ -9,14 +9,11 @@ import org.jetbrains.kotlin.fir.expressions.impl.FirQualifiedAccessExpressionImp
 import org.jetbrains.kotlin.fir.resolve.transformers.firUnsafe
 import org.jetbrains.kotlin.fir.symbols.ConeCallableSymbol
 import org.jetbrains.kotlin.util.OperatorNameConventions
-import kotlin.coroutines.Continuation
-import kotlin.coroutines.CoroutineContext
-import kotlin.coroutines.EmptyCoroutineContext
-import kotlin.coroutines.intrinsics.createCoroutineUnintercepted
-import kotlin.coroutines.resume
-
-open class CandidateCollector(val components: InferenceComponents) {
 
+open class CandidateCollector(
+    val components: InferenceComponents,
+    val resolutionStageRunner: ResolutionStageRunner
+) {
     val groupNumbers = mutableListOf<Int>()
     val candidates = mutableListOf<Candidate>()
 
@@ -28,37 +25,8 @@ open class CandidateCollector(val components: InferenceComponents) {
         currentApplicability = CandidateApplicability.HIDDEN
     }
 
-    private fun getApplicability(
-        group: Int,
-        candidate: Candidate
-    ): CandidateApplicability {
-        val sink = CheckerSinkImpl(components)
-        var finished = false
-        sink.continuation = suspend {
-            for (stage in candidate.callInfo.callKind.sequence()) {
-                stage.check(candidate, sink, candidate.callInfo)
-            }
-        }.createCoroutineUnintercepted(completion = object : Continuation<Unit> {
-            override val context: CoroutineContext
-                get() = EmptyCoroutineContext
-
-            override fun resumeWith(result: Result<Unit>) {
-                result.exceptionOrNull()?.let { throw it }
-                finished = true
-            }
-        })
-
-        while (!finished) {
-            sink.continuation!!.resume(Unit)
-            if (sink.current < CandidateApplicability.SYNTHETIC_RESOLVED) {
-                break
-            }
-        }
-        return sink.current
-    }
-
     open fun consumeCandidate(group: Int, candidate: Candidate): CandidateApplicability {
-        val applicability = getApplicability(group, candidate)
+        val applicability = resolutionStageRunner.processCandidate(candidate)
 
         if (applicability > currentApplicability) {
             groupNumbers.clear()
@@ -103,8 +71,9 @@ class InvokeReceiverCandidateCollector(
     val callResolver: CallResolver,
     val invokeCallInfo: CallInfo,
     components: InferenceComponents,
-    val invokeConsumer: AccumulatingTowerDataConsumer
+    val invokeConsumer: AccumulatingTowerDataConsumer,
-) : CandidateCollector(components) {
+    resolutionStageRunner: ResolutionStageRunner
+) : CandidateCollector(components, resolutionStageRunner) {
     override fun consumeCandidate(group: Int, candidate: Candidate): CandidateApplicability {
         val applicability = super.consumeCandidate(group, candidate)
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConsumerFactories.kt

@@ -94,7 +94,8 @@ fun createFunctionConsumer(
                     callResolver,
                     invokeCallInfo = callInfo,
                     components = inferenceComponents,
-                    invokeConsumer = this
+                    invokeConsumer = this,
+                    resolutionStageRunner = resultCollector.resolutionStageRunner
                 )
             )
         }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ResolutionStageRunner.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.fir.resolve.calls
+
+import kotlin.coroutines.Continuation
+import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.EmptyCoroutineContext
+import kotlin.coroutines.intrinsics.createCoroutineUnintercepted
+import kotlin.coroutines.resume
+
+class ResolutionStageRunner(val components: InferenceComponents) {
+    fun processCandidate(candidate: Candidate): CandidateApplicability {
+        val sink = CheckerSinkImpl(components)
+        var finished = false
+        sink.continuation = suspend {
+            for (stage in candidate.callInfo.callKind.sequence()) {
+                stage.check(candidate, sink, candidate.callInfo)
+            }
+        }.createCoroutineUnintercepted(completion = object : Continuation<Unit> {
+            override val context: CoroutineContext
+                get() = EmptyCoroutineContext
+
+            override fun resumeWith(result: Result<Unit>) {
+                result.exceptionOrNull()?.let { throw it }
+                finished = true
+            }
+        })
+
+        while (!finished) {
+            sink.continuation!!.resume(Unit)
+            if (sink.current < CandidateApplicability.SYNTHETIC_RESOLVED) {
+                break
+            }
+        }
+        return sink.current
+    }
+}

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirBodyResolveTransformer.kt

@@ -71,7 +71,16 @@ open class FirBodyResolveTransformer(
 
     private val callCompleter: FirCallCompleter = FirCallCompleter(this, inferenceComponents)
     private val qualifiedResolver: FirQualifiedNameResolver = FirQualifiedNameResolver(this)
-    private val callResolver: FirCallResolver = FirCallResolver(this, inferenceComponents, scopes, localScopes, implicitReceiverStack, qualifiedResolver)
+    private val resolutionStageRunner: ResolutionStageRunner = ResolutionStageRunner(inferenceComponents)
+    private val callResolver: FirCallResolver = FirCallResolver(
+        this,
+        inferenceComponents,
+        scopes,
+        localScopes,
+        implicitReceiverStack,
+        qualifiedResolver,
+        resolutionStageRunner
+    )
 
     override fun transformFile(file: FirFile, data: Any?): CompositeTransformResult<FirFile> {
         packageFqName = file.packageFqName