Quick Fixes: Implement quick-fix for increasing module language level to enable unsupported language features

#KT-15205 Fixed

ChangeLog.md

@@ -126,6 +126,9 @@
 
 ### IDE
 
+- [`KT-15205`](https://youtrack.jetbrains.com/issue/KT-15205) Implement quick-fix for increasing module language level to enable unsupported language features
+
+###### Issues fixed
 - [`KT-14693`](https://youtrack.jetbrains.com/issue/KT-14693) Introduce Type Alias: Do not suggest type qualifiers
 - [`KT-14696`](https://youtrack.jetbrains.com/issue/KT-14696) Introduce Type Alias: Fix NPE during dialog repaint
 - [`KT-14685`](https://youtrack.jetbrains.com/issue/KT-14685) Introduce Type Alias: Replace type usages in constructor calls

idea/src/org/jetbrains/kotlin/idea/quickfix/EnableUnsupportedFeatureFix.kt

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2010-2016 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.idea.quickfix
+
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.module.ModuleUtilCore
+import com.intellij.openapi.project.Project
+import com.intellij.openapi.roots.ModuleRootModificationUtil
+import com.intellij.openapi.roots.ex.ProjectRootManagerEx
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.config.LanguageVersion
+import org.jetbrains.kotlin.diagnostics.Diagnostic
+import org.jetbrains.kotlin.diagnostics.Errors
+import org.jetbrains.kotlin.idea.KotlinPluginUtil
+import org.jetbrains.kotlin.idea.compiler.configuration.KotlinCommonCompilerArgumentsHolder
+import org.jetbrains.kotlin.idea.facet.KotlinFacet
+import org.jetbrains.kotlin.psi.KtFile
+
+sealed class EnableUnsupportedFeatureFix(
+        element: PsiElement,
+        protected val targetVersion: LanguageVersion
+) : KotlinQuickFixAction<PsiElement>(element) {
+    class InModule(element: PsiElement, targetVersion: LanguageVersion) : EnableUnsupportedFeatureFix(element, targetVersion) {
+        override fun getFamilyName() = "Increase module language level"
+
+        override fun getText() = "Set module language level to ${targetVersion.versionString}"
+
+        override fun invoke(project: Project, editor: Editor?, file: KtFile) {
+            val module = ModuleUtilCore.findModuleForPsiElement(file) ?: return
+            val facetSettings = KotlinFacet.get(module)?.configuration?.settings ?: return
+            ModuleRootModificationUtil.updateModel(module) {
+                facetSettings.versionInfo.languageLevel = targetVersion
+            }
+        }
+    }
+
+    class InProject(element: PsiElement, targetVersion: LanguageVersion) : EnableUnsupportedFeatureFix(element, targetVersion) {
+        override fun getFamilyName() = "Increase project language level"
+
+        override fun getText() = "Set project language level to ${targetVersion.versionString}"
+
+        override fun invoke(project: Project, editor: Editor?, file: KtFile) {
+            KotlinCommonCompilerArgumentsHolder.getInstance(project).settings.languageVersion = targetVersion.versionString
+            ProjectRootManagerEx.getInstanceEx(project).makeRootsChange({}, false, true)
+        }
+    }
+
+    companion object : KotlinSingleIntentionActionFactory() {
+        override fun createAction(diagnostic: Diagnostic): EnableUnsupportedFeatureFix? {
+            val targetVersion = Errors.UNSUPPORTED_FEATURE.cast(diagnostic).a.sinceVersion ?: return null
+            val module = ModuleUtilCore.findModuleForPsiElement(diagnostic.psiElement) ?: return null
+            if (KotlinPluginUtil.isGradleModule(module) || KotlinPluginUtil.isMavenModule(module)) return null
+            val facetSettings = KotlinFacet.get(module)?.configuration?.settings
+            if (facetSettings == null || facetSettings.useProjectSettings) return InProject(diagnostic.psiElement, targetVersion)
+            return InModule(diagnostic.psiElement, targetVersion)
+        }
+    }
+}

idea/src/org/jetbrains/kotlin/idea/quickfix/QuickFixRegistrar.kt

@@ -467,5 +467,7 @@ class QuickFixRegistrar : QuickFixContributor {
         CAST_NEVER_SUCCEEDS.registerFactory(ReplacePrimitiveCastWithNumberConversionFix)
 
         ErrorsJs.WRONG_EXTERNAL_DECLARATION.registerFactory(MigrateExternalExtensionFix)
+
+        UNSUPPORTED_FEATURE.registerFactory(EnableUnsupportedFeatureFix)
     }
 }