Support "-language-version" CLI option for compatibility with older releases

Introduce LanguageFeatureSettings, instance of which should be injected by the
container and be accessible everywhere during the compilation (front-end and
back-end).

Parameters of LanguageFeatureSettings are unused in this commit, will be used
later

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

@@ -25,6 +25,10 @@ import java.util.List;
 public abstract class CommonCompilerArguments {
     public static final String PLUGIN_OPTION_FORMAT = "plugin:<pluginId>:<optionName>=<value>";
 
+    @Argument(value = "language-version", description = "Provide source compatibility with specified language version")
+    @ValueDescription("<version>")
+    public String languageVersion;
+
     @Argument(value = "nowarn", description = "Generate no warnings")
     public boolean suppressWarnings;
 

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

@@ -34,6 +34,7 @@ import org.jetbrains.kotlin.cli.jvm.compiler.CompileEnvironmentException;
 import org.jetbrains.kotlin.cli.jvm.compiler.CompilerJarLocator;
 import org.jetbrains.kotlin.config.CommonConfigurationKeys;
 import org.jetbrains.kotlin.config.CompilerConfiguration;
+import org.jetbrains.kotlin.config.LanguageFeatureSettings;
 import org.jetbrains.kotlin.config.Services;
 import org.jetbrains.kotlin.progress.CompilationCanceledException;
 import org.jetbrains.kotlin.progress.CompilationCanceledStatus;
@@ -242,6 +243,13 @@ public abstract class CLICompiler<A extends CommonCompilerArguments> {
         if (locator != null) {
             configuration.put(CLIConfigurationKeys.COMPILER_JAR_LOCATOR, locator);
         }
+
+        if (arguments.languageVersion != null) {
+            configuration.put(
+                    CommonConfigurationKeys.LANGUAGE_FEATURE_SETTINGS,
+                    LanguageFeatureSettings.fromLanguageVersion(arguments.languageVersion)
+            );
+        }
     }
 
     protected abstract void setupPlatformSpecificArgumentsAndServices(

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/repl/di/injection.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.cli.jvm.repl.di
 
 import com.intellij.psi.search.GlobalSearchScope
+import org.jetbrains.kotlin.config.LanguageFeatureSettings
 import org.jetbrains.kotlin.container.*
 import org.jetbrains.kotlin.context.ModuleContext
 import org.jetbrains.kotlin.descriptors.PackagePartProvider
@@ -43,7 +44,7 @@ fun createContainerForReplWithJava(
 ): ContainerForReplWithJava = createContainer("ReplWithJava") {
     useInstance(packagePartProvider)
     configureModule(moduleContext, JvmPlatform, bindingTrace)
-    configureJavaTopDownAnalysis(moduleContentScope, moduleContext.project, LookupTracker.DO_NOTHING)
+    configureJavaTopDownAnalysis(moduleContentScope, moduleContext.project, LookupTracker.DO_NOTHING, LanguageFeatureSettings.LATEST)
 
     useInstance(declarationProviderFactory)