K2: move -Xuse-k2 VS language version checks to CommonCompilerArguments

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/CommonCompilerArguments.kt

@@ -602,10 +602,7 @@ abstract class CommonCompilerArguments : CommonToolArguments() {
         collector: MessageCollector,
         additionalAnalysisFlags: Map<AnalysisFlag<*>, Any>
     ): LanguageVersionSettings {
-        // If only "-api-version" is specified, language version is assumed to be the latest stable
+        val languageVersion = parseOrConfigureLanguageVersion(collector)
-        val languageVersion = parseVersion(collector, languageVersion, "language")
-            ?: defaultLanguageVersion(collector)
-
         // If only "-language-version" is specified, API version is assumed to be equal to the language version
         // (API version cannot be greater than the language version)
         val apiVersion = ApiVersion.createByLanguageVersion(parseVersion(collector, apiVersion, "API") ?: languageVersion)
@@ -709,6 +706,37 @@ abstract class CommonCompilerArguments : CommonToolArguments() {
         LANGUAGE("Language"), API("API")
     }
 
+    private fun parseOrConfigureLanguageVersion(collector: MessageCollector): LanguageVersion {
+        // If only "-api-version" is specified, language version is assumed to be the latest stable (or 2.0 with -Xuse-k2)
+        val explicitVersion = parseVersion(collector, languageVersion, "language")
+        val explicitOrDefaultVersion = explicitVersion ?: defaultLanguageVersion(collector)
+        if (useK2) {
+            when {
+                explicitVersion?.usesK2 == true -> {
+                    collector.report(
+                        CompilerMessageSeverity.STRONG_WARNING,
+                        "Compiler flag -Xuse-k2 is redundant, the \"-language-version 2.0\" is used instead"
+                    )
+                }
+                explicitVersion != null -> {
+                    collector.report(
+                        CompilerMessageSeverity.STRONG_WARNING,
+                        "With -Xuse-k2 compiler flag \"-language-version $explicitVersion\" has no effect," +
+                                " please remove -Xuse-k2 flag and use \"-language-version 2.0\" instead"
+                    )
+                }
+                else -> {
+                    collector.report(
+                        CompilerMessageSeverity.STRONG_WARNING,
+                        "Compiler flag -Xuse-k2 is deprecated, please use \"-language-version 2.0\" instead"
+                    )
+                }
+            }
+        }
+        return if (useK2 && !explicitOrDefaultVersion.usesK2) LanguageVersion.KOTLIN_2_0
+        else explicitOrDefaultVersion
+    }
+
     private fun parseVersion(collector: MessageCollector, value: String?, versionOf: String): LanguageVersion? =
         if (value == null) null
         else LanguageVersion.fromVersionString(value)

compiler/cli/src/org/jetbrains/kotlin/cli/common/CLICompiler.kt

@@ -97,36 +97,6 @@ abstract class CLICompiler<A : CommonCompilerArguments> : CLITool<A>() {
             try {
                 setIdeaIoUseFallback()
 
-                val useK2FromFlag = arguments.useK2
-                val languageVersion = configuration.languageVersionSettings.languageVersion
-                if (useK2FromFlag) {
-                    when {
-                        arguments.languageVersion == null -> {
-                            messageCollector.report(
-                                STRONG_WARNING,
-                                "Compiler flag -Xuse-k2 is deprecated, please use \"-language-version 2.0\" instead"
-                            )
-                        }
-                        languageVersion.usesK2 -> {
-                            messageCollector.report(
-                                STRONG_WARNING,
-                                "Compiler flag -Xuse-k2 is redundant, the \"-language-version 2.0\" is used instead"
-                            )
-                        }
-                        else -> {
-                            messageCollector.report(
-                                STRONG_WARNING,
-                                "With -Xuse-k2 compiler flag \"-language-version $languageVersion\" has no effect, please remove -Xuse-k2 flag and use \"-language-version 2.0\" instead"
-                            )
-                        }
-                    }
-                    if (!languageVersion.usesK2) {
-                        val languageVersionSettings = configuration.languageVersionSettings
-                        configuration.languageVersionSettings = languageVersionSettings.copy(LanguageVersion.KOTLIN_2_0)
-                        arguments.checkLanguageVersionIsStable(LanguageVersion.KOTLIN_2_0, messageCollector)
-                    }
-                }
-
                 val code = doExecute(arguments, configuration, rootDisposable, paths)
 
                 performanceManager.notifyCompilationFinished()

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

@@ -108,8 +108,6 @@ object FirSessionFactoryHelper {
 
                     override fun <T> getFlag(flag: AnalysisFlag<T>): T = stub()
 
-                    override fun copy(languageVersion: LanguageVersion): LanguageVersionSettings = this
-
                     override val apiVersion: ApiVersion
                         get() = stub()
                     override val languageVersion: LanguageVersion

compiler/tests-common/tests/org/jetbrains/kotlin/checkers/CompilerTestLanguageVersionSettings.kt

@@ -39,10 +39,6 @@ data class CompilerTestLanguageVersionSettings(
 
     override fun isPreRelease(): Boolean = false
 
-    override fun copy(languageVersion: LanguageVersion): LanguageVersionSettings {
-        return CompilerTestLanguageVersionSettings(initialLanguageFeatures, apiVersion, languageVersion, analysisFlags)
-    }
-
     @Suppress("UNCHECKED_CAST")
     override fun <T> getFlag(flag: AnalysisFlag<T>): T = analysisFlags[flag] as T? ?: flag.defaultValue
 }

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

@@ -507,8 +507,6 @@ 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"
     }
@@ -557,9 +555,6 @@ 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)