Refactor skipMetadataVersionCheck flag

To make addition of other flags easier in the future, provide a more
abstract 'isFlagEnabled' in LanguageVersionSettings

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

@@ -279,15 +279,10 @@ public abstract class CLICompiler<A extends CommonCompilerArguments> {
             extraLanguageFeatures.put(LanguageFeature.Coroutines, coroutinesState);
         }
 
-        CommonConfigurationKeysKt.setLanguageVersionSettings(
-                configuration,
-                new LanguageVersionSettingsImpl(
-                        languageVersion,
-                        ApiVersion.createByLanguageVersion(apiVersion),
-                        arguments.skipMetadataVersionCheck,
-                        extraLanguageFeatures
-                )
-        );
+        LanguageVersionSettingsImpl settings =
+                new LanguageVersionSettingsImpl(languageVersion, ApiVersion.createByLanguageVersion(apiVersion), extraLanguageFeatures);
+        settings.switchFlag(AnalysisFlags.getSkipMetadataVersionCheck(), arguments.skipMetadataVersionCheck);
+        CommonConfigurationKeysKt.setLanguageVersionSettings(configuration, settings);
     }
 
     @Nullable

compiler/daemon/src/org/jetbrains/kotlin/daemon/KotlinRemoteReplService.kt

@@ -53,7 +53,9 @@ open class KotlinJvmReplService(
         addJvmClasspathRoots(templateClasspath)
         put(CommonConfigurationKeys.MODULE_NAME, "kotlin-script")
         put(CommonConfigurationKeys.LANGUAGE_VERSION_SETTINGS,
-            LanguageVersionSettingsImpl(LanguageVersion.LATEST, ApiVersion.LATEST, skipMetadataVersionCheck = true))
+            LanguageVersionSettingsImpl(LanguageVersion.LATEST, ApiVersion.LATEST).apply {
+                switchFlag(AnalysisFlags.skipMetadataVersionCheck, true)
+            })
     }
 
     protected fun makeScriptDefinition(templateClasspath: List<File>, templateClassName: String): KotlinScriptDefinition? {

compiler/frontend/src/org/jetbrains/kotlin/resolve/CompilerDeserializationConfiguration.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.resolve
 
+import org.jetbrains.kotlin.config.AnalysisFlags
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.serialization.deserialization.DeserializationConfiguration
@@ -23,5 +24,5 @@ import org.jetbrains.kotlin.serialization.deserialization.DeserializationConfigu
 class CompilerDeserializationConfiguration(languageVersionSettings: LanguageVersionSettings) : DeserializationConfiguration {
     override val typeAliasesAllowed = languageVersionSettings.supportsFeature(LanguageFeature.TypeAliases)
 
-    override val skipMetadataVersionCheck = languageVersionSettings.skipMetadataVersionCheck
+    override val skipMetadataVersionCheck = languageVersionSettings.isFlagEnabled(AnalysisFlags.skipMetadataVersionCheck)
 }

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

@@ -108,7 +108,7 @@ abstract class BaseDiagnosticsTest : KotlinMultiFileTestWithJava<TestModule, Tes
         override fun getFeatureSupport(feature: LanguageFeature): LanguageFeature.State =
                 languageFeatures[feature] ?: delegate.getFeatureSupport(feature)
 
-        override val skipMetadataVersionCheck: Boolean get() = false
+        override fun isFlagEnabled(flag: AnalysisFlag): Boolean = false
     }
 
     inner class TestFile(

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

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.config
+
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+class AnalysisFlag internal constructor(private val name: String) {
+    override fun equals(other: Any?): Boolean = other is AnalysisFlag && other.name == name
+
+    override fun hashCode(): Int = name.hashCode()
+
+    override fun toString(): String = name
+
+    companion object
+}
+
+private operator fun AnalysisFlag.Companion.provideDelegate(instance: Any?, property: KProperty<*>) =
+        object : ReadOnlyProperty<Any?, AnalysisFlag> {
+            private val flag = AnalysisFlag(property.name)
+
+            override fun getValue(thisRef: Any?, property: KProperty<*>): AnalysisFlag = flag
+        }
+
+object AnalysisFlags {
+    @JvmStatic
+    val skipMetadataVersionCheck by AnalysisFlag
+}

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

@@ -106,20 +106,32 @@ interface LanguageVersionSettings {
     fun supportsFeature(feature: LanguageFeature): Boolean =
             getFeatureSupport(feature).let { it == LanguageFeature.State.ENABLED || it == LanguageFeature.State.ENABLED_WITH_WARNING }
 
+    fun isFlagEnabled(flag: AnalysisFlag): Boolean
+
     val apiVersion: ApiVersion
 
     // Please do not use this to enable/disable specific features/checks. Instead add a new LanguageFeature entry and call supportsFeature
     val languageVersion: LanguageVersion
-
-    val skipMetadataVersionCheck: Boolean
 }
 
 class LanguageVersionSettingsImpl @JvmOverloads constructor(
         override val languageVersion: LanguageVersion,
         override val apiVersion: ApiVersion,
-        override val skipMetadataVersionCheck: Boolean = false,
         private val specificFeatures: Map<LanguageFeature, LanguageFeature.State> = emptyMap()
 ) : LanguageVersionSettings {
+    private val enabledFlags = hashSetOf<AnalysisFlag>()
+
+    override fun isFlagEnabled(flag: AnalysisFlag): Boolean = flag in enabledFlags
+
+    fun switchFlag(flag: AnalysisFlag, enable: Boolean) {
+        if (enable) {
+            enabledFlags.add(flag)
+        }
+        else {
+            enabledFlags.remove(flag)
+        }
+    }
+
     override fun getFeatureSupport(feature: LanguageFeature): LanguageFeature.State {
         specificFeatures[feature]?.let { return it }
 

idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/Platform.kt

@@ -90,12 +90,9 @@ fun Project.getLanguageVersionSettings(contextModule: Module? = null): LanguageV
             compilerSettings,
             null
     )
-    return LanguageVersionSettingsImpl(
-            languageVersion,
-            apiVersion,
-            arguments.skipMetadataVersionCheck,
-            extraLanguageFeatures
-    )
+    return LanguageVersionSettingsImpl(languageVersion, apiVersion, extraLanguageFeatures).apply {
+        switchFlag(AnalysisFlags.skipMetadataVersionCheck, arguments.skipMetadataVersionCheck)
+    }
 }
 
 val Module.languageVersionSettings: LanguageVersionSettings
@@ -112,12 +109,9 @@ val Module.languageVersionSettings: LanguageVersionSettings
                 this
         )
 
-        return LanguageVersionSettingsImpl(
-                languageVersion,
-                ApiVersion.createByLanguageVersion(apiVersion),
-                facetSettings.skipMetadataVersionCheck,
-                extraLanguageFeatures
-        )
+        return LanguageVersionSettingsImpl(languageVersion, ApiVersion.createByLanguageVersion(apiVersion), extraLanguageFeatures).apply {
+            switchFlag(AnalysisFlags.skipMetadataVersionCheck, facetSettings.skipMetadataVersionCheck)
+        }
     }
 
 val Module.targetPlatform: TargetPlatformKind<*>?