[FIR] Extract language settings into a dedicated component

^KT-42080 Fixed

compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/session/ComponentsContainers.kt

@@ -34,6 +34,7 @@ fun FirSession.registerCommonComponents() {
     register(FirRegisteredPluginAnnotations::class, FirRegisteredPluginAnnotations.create(this))
     register(FirPredicateBasedProvider::class, FirPredicateBasedProvider.create(this))
     register(GeneratedClassIndex::class, GeneratedClassIndex.create())
+    register(FirLanguageSettingsComponent::class, FirLanguageSettingsComponent(this))
     register(InferenceComponents::class, InferenceComponents(this))
 }
 

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

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2010-2020 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
+
+import org.jetbrains.kotlin.config.LanguageVersionSettings
+import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl
+
+@NoMutableState
+class FirLanguageSettingsComponent(val session: FirSession) : FirSessionComponent {
+    val languageVersionSettings: LanguageVersionSettings =
+        LanguageVersionSettingsImpl.DEFAULT // TODO
+}
+
+val FirSession.languageSettingsComponent: FirLanguageSettingsComponent by FirSession.sessionComponentAccessor()
+
+val FirSession.languageVersionSettings: LanguageVersionSettings
+    get() = languageSettingsComponent.languageVersionSettings

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/ConstraintSystemCompleter.kt

@@ -30,10 +30,8 @@ import org.jetbrains.kotlin.utils.addIfNotNull
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 class ConstraintSystemCompleter(private val components: BodyResolveComponents) {
-    private val inferenceComponents
+    private val inferenceComponents = components.session.inferenceComponents
-        get() = components.session.inferenceComponents
+    val variableFixationFinder = inferenceComponents.variableFixationFinder
-    val variableFixationFinder
-        get() = inferenceComponents.variableFixationFinder
 
     fun complete(
         c: ConstraintSystemCompletionContext,

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/InferenceComponents.kt

@@ -5,11 +5,7 @@
 
 package org.jetbrains.kotlin.fir.resolve.inference
 
-import org.jetbrains.kotlin.config.LanguageVersionSettings
+import org.jetbrains.kotlin.fir.*
-import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl
-import org.jetbrains.kotlin.fir.FirSession
-import org.jetbrains.kotlin.fir.FirSessionComponent
-import org.jetbrains.kotlin.fir.NoMutableState
 import org.jetbrains.kotlin.fir.types.ConeInferenceContext
 import org.jetbrains.kotlin.fir.types.ConeTypeCheckerContext
 import org.jetbrains.kotlin.resolve.calls.inference.components.*
@@ -19,7 +15,6 @@ import org.jetbrains.kotlin.types.AbstractTypeApproximator
 @NoMutableState
 class InferenceComponents(val session: FirSession) : FirSessionComponent {
     val ctx: ConeTypeCheckerContext = ConeTypeCheckerContext(isErrorTypeEqualsToAnything = false, isStubTypeEqualsToAnything = false, session)
-    val languageVersionSettings: LanguageVersionSettings = LanguageVersionSettingsImpl.DEFAULT // TODO
 
     val approximator: AbstractTypeApproximator = object : AbstractTypeApproximator(ctx) {}
     val trivialConstraintTypeInferenceOracle = TrivialConstraintTypeInferenceOracle.create(ctx)
@@ -27,13 +22,13 @@ class InferenceComponents(val session: FirSession) : FirSessionComponent {
     private val injector = ConstraintInjector(
         incorporator,
         approximator,
-        languageVersionSettings,
+        session.languageVersionSettings,
     )
     val resultTypeResolver = ResultTypeResolver(approximator, trivialConstraintTypeInferenceOracle)
 
     val constraintSystemFactory = ConstraintSystemFactory()
 
-    val variableFixationFinder = VariableFixationFinder(trivialConstraintTypeInferenceOracle, languageVersionSettings)
+    val variableFixationFinder = VariableFixationFinder(trivialConstraintTypeInferenceOracle, session.languageVersionSettings)
 
     fun createConstraintSystem(): NewConstraintSystemImpl {
         return NewConstraintSystemImpl(injector, ctx)