Introduce language version 2.0 and associate K2 compiler with it

compiler/util/src/org/jetbrains/kotlin/config/ApiVersion.kt

@@ -63,6 +63,9 @@ class ApiVersion private constructor(
         @JvmField
         val KOTLIN_1_9 = createByLanguageVersion(LanguageVersion.KOTLIN_1_9)
 
+        @JvmField
+        val KOTLIN_2_0 = createByLanguageVersion(LanguageVersion.KOTLIN_2_0)
+
         @JvmField
         val LATEST: ApiVersion = createByLanguageVersion(LanguageVersion.values().last())
 

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -282,6 +282,11 @@ enum class LanguageFeature(
     ValueClassesSecondaryConstructorWithBody(sinceVersion = KOTLIN_1_9, kind = UNSTABLE_FEATURE), // KT-55333
     NativeJsProhibitLateinitIsInitalizedIntrinsicWithoutPrivateAccess(KOTLIN_1_9, kind = BUG_FIX), // KT-27002
 
+    // End of 1.* language features --------------------------------------------------
+
+    // 2.0
+
+    // End of 2.* language features --------------------------------------------------
 
     // This feature effectively might be removed because we decided to disable it until K2 and there it will be unconditionally enabled.
     // But we leave it here just to minimize the changes in K1 and also to allow use the feature once somebody needs it.
@@ -414,11 +419,16 @@ enum class LanguageVersion(val major: Int, val minor: Int) : DescriptionAware, L
     KOTLIN_1_7(1, 7),
     KOTLIN_1_8(1, 8),
     KOTLIN_1_9(1, 9),
+
+    KOTLIN_2_0(2, 0),
     ;
 
     override val isStable: Boolean
         get() = this <= LATEST_STABLE
 
+    val usesK2: Boolean
+        get() = this >= KOTLIN_2_0
+
     override val isDeprecated: Boolean
         get() = FIRST_SUPPORTED <= this && this < FIRST_NON_DEPRECATED
 
@@ -498,6 +508,8 @@ interface LanguageVersionSettings {
     // Please do not use this to enable/disable specific features/checks. Instead add a new LanguageFeature entry and call supportsFeature
     val languageVersion: LanguageVersion
 
+    fun copy(languageVersion: LanguageVersion): LanguageVersionSettings = this
+
     companion object {
         const val RESOURCE_NAME_TO_ALLOW_READING_FROM_ENVIRONMENT = "META-INF/allow-configuring-from-environment"
     }
@@ -546,6 +558,9 @@ class LanguageVersionSettingsImpl @JvmOverloads constructor(
                 state == LanguageFeature.State.ENABLED && feature.forcesPreReleaseBinariesIfEnabled()
             }
 
+    override fun copy(languageVersion: LanguageVersion): LanguageVersionSettings =
+        LanguageVersionSettingsImpl(languageVersion, apiVersion, analysisFlags, specificFeatures)
+
     companion object {
         @JvmField
         val DEFAULT = LanguageVersionSettingsImpl(LanguageVersion.LATEST_STABLE, ApiVersion.LATEST_STABLE)