Remove obsolete check for language version and IR backends

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

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity
 import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity.WARNING
 import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.config.*
-import java.util.*
 
 @SuppressWarnings("WeakerAccess")
 abstract class CommonCompilerArguments : CommonToolArguments() {
@@ -563,8 +562,6 @@ abstract class CommonCompilerArguments : CommonToolArguments() {
             checkLanguageVersionIsStable(languageVersion, collector)
             checkOutdatedVersions(languageVersion, apiVersion, collector)
             checkProgressiveMode(languageVersion, collector)
-
-            checkIrSupport(languageVersionSettings, collector)
         }
 
         return languageVersionSettings
@@ -635,10 +632,6 @@ abstract class CommonCompilerArguments : CommonToolArguments() {
         }
     }
 
-    protected open fun checkIrSupport(languageVersionSettings: LanguageVersionSettings, collector: MessageCollector) {
-        // backend-specific
-    }
-
     private enum class VersionKind(val text: String) {
         LANGUAGE("Language"), API("API")
     }

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JSCompilerArguments.kt

@@ -6,12 +6,8 @@
 package org.jetbrains.kotlin.cli.common.arguments
 
 import org.jetbrains.kotlin.cli.common.arguments.K2JsArgumentConstants.*
-import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity
 import org.jetbrains.kotlin.cli.common.messages.MessageCollector
-import org.jetbrains.kotlin.config.ApiVersion
 import org.jetbrains.kotlin.config.LanguageFeature
-import org.jetbrains.kotlin.config.LanguageVersion
-import org.jetbrains.kotlin.config.LanguageVersionSettings
 
 class K2JSCompilerArguments : CommonCompilerArguments() {
     companion object {
@@ -236,19 +232,6 @@ class K2JSCompilerArguments : CommonCompilerArguments() {
     @Argument(value = "-Xwasm", description = "Use experimental WebAssembly compiler backend")
     var wasm: Boolean by FreezableVar(false)
 
-    override fun checkIrSupport(languageVersionSettings: LanguageVersionSettings, collector: MessageCollector) {
-        if (!isIrBackendEnabled()) return
-
-        if (languageVersionSettings.languageVersion < LanguageVersion.KOTLIN_1_4
-            || languageVersionSettings.apiVersion < ApiVersion.KOTLIN_1_4
-        ) {
-            collector.report(
-                CompilerMessageSeverity.ERROR,
-                "IR backend cannot be used with language or API version below 1.4"
-            )
-        }
-    }
-
     override fun configureLanguageFeatures(collector: MessageCollector): MutableMap<LanguageFeature, LanguageFeature.State> {
         return super.configureLanguageFeatures(collector).apply {
             if (extensionFunctionsInExternals) {

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JVMCompilerArguments.kt

@@ -557,18 +557,4 @@ default: `indy-with-constants` for JVM target 9 or greater, `inline` otherwise""
         }
         return result
     }
-
-    override fun checkIrSupport(languageVersionSettings: LanguageVersionSettings, collector: MessageCollector) {
-        if (!useIR || useOldBackend) return
-
-        if (languageVersionSettings.languageVersion < LanguageVersion.KOTLIN_1_3
-            || languageVersionSettings.apiVersion < ApiVersion.KOTLIN_1_3
-        ) {
-            collector.report(
-                CompilerMessageSeverity.STRONG_WARNING,
-                "IR backend does not support language or API version lower than 1.3. " +
-                        "This can lead to unexpected behavior or compilation failures"
-            )
-        }
-    }
 }

kotlin-native/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt

@@ -358,17 +358,6 @@ class K2NativeCompilerArguments : CommonCompilerArguments() {
                 if (printIr)
                     phasesToDumpAfter = arrayOf("ALL")
             }
-
-    override fun checkIrSupport(languageVersionSettings: LanguageVersionSettings, collector: MessageCollector) {
-        if (languageVersionSettings.languageVersion < LanguageVersion.KOTLIN_1_4
-                || languageVersionSettings.apiVersion < ApiVersion.KOTLIN_1_4
-        ) {
-            collector.report(
-                    severity = CompilerMessageSeverity.ERROR,
-                    message = "Native backend cannot be used with language or API version below 1.4"
-            )
-        }
-    }
 }
 
 const val EMBED_BITCODE_FLAG = "-Xembed-bitcode"