LC: introduce light class interface for facade

so that FIR-based light class for facade can work well in LC utils

compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/FacadeCache.kt

@@ -17,7 +17,7 @@ import org.jetbrains.kotlin.name.FqName
 
 private data class FacadeCacheKey(val fqName: FqName, val searchScope: GlobalSearchScope)
 
-private data class ValueWrapper(val value: KtLightClassForFacadeImpl?) {
+private data class ValueWrapper(val value: KtLightClassForFacade?) {
     companion object {
         val Null = ValueWrapper(null)
     }
@@ -42,7 +42,7 @@ class FacadeCache(private val project: Project) {
         }, false
     )
 
-    operator fun get(qualifiedName: FqName, searchScope: GlobalSearchScope): KtLightClassForFacadeImpl? {
+    operator fun get(qualifiedName: FqName, searchScope: GlobalSearchScope): KtLightClassForFacade? {
         synchronized(cachedValue) {
             return cachedValue.value.cache.get(FacadeCacheKey(qualifiedName, searchScope)).value
         }

compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/KtLightClassForFacade.kt

@@ -0,0 +1,16 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.asJava.classes
+
+import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.psi.KtFile
+
+interface KtLightClassForFacade : KtLightClass {
+    val facadeClassFqName: FqName
+    val files: Collection<KtFile>
+
+    override fun getName() = facadeClassFqName.shortName().asString()
+}

compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/KtLightClassForFacadeImpl.kt

@@ -47,10 +47,10 @@ import javax.swing.Icon
 
 open class KtLightClassForFacadeImpl constructor(
     manager: PsiManager,
-    protected val facadeClassFqName: FqName,
+    override val facadeClassFqName: FqName,
     myLightClassDataCache: CachedValue<LightClassDataHolder.ForFacade>,
-    files: Collection<KtFile>
-) : KtLazyLightClass(manager) {
+    override val files: Collection<KtFile>
+) : KtLazyLightClass(manager), KtLightClassForFacade {
 
     protected open val lightClassDataCache: CachedValue<LightClassDataHolder.ForFacade> = myLightClassDataCache
 
@@ -60,8 +60,6 @@ open class KtLightClassForFacadeImpl constructor(
     override val lightClassData
         get() = lightClassDataCache.value.findDataForFacade(facadeClassFqName)
 
-    val files: Collection<KtFile> = files.toSet()
-
     private val firstFileInFacade by lazyPub { files.iterator().next() }
 
     private val hashCode: Int =
@@ -138,7 +136,7 @@ open class KtLightClassForFacadeImpl constructor(
 
     override fun getRBrace(): PsiElement? = null
 
-    override fun getName() = facadeClassFqName.shortName().asString()
+    override fun getName() = super<KtLightClassForFacade>.getName()
 
     override fun setName(name: String): PsiElement? {
         for (file in files) {
@@ -184,13 +182,14 @@ open class KtLightClassForFacadeImpl constructor(
 
     override fun isValid() = files.all { it.isValid && it.hasTopLevelCallables() && facadeClassFqName == it.javaFileFacadeFqName }
 
-    override fun copy() = KtLightClassForFacadeImpl(manager, facadeClassFqName, lightClassDataCache, files)
+    override fun copy(): KtLightClassForFacade =
+        KtLightClassForFacadeImpl(manager, facadeClassFqName, lightClassDataCache, files)
 
     override fun getNavigationElement() = firstFileInFacade
 
     override fun isEquivalentTo(another: PsiElement?): Boolean =
         equals(another) ||
-                (another is KtLightClassForFacadeImpl && another.facadeClassFqName == facadeClassFqName)
+                (another is KtLightClassForFacade && another.facadeClassFqName == facadeClassFqName)
 
     override fun getElementIcon(flags: Int): Icon? = throw UnsupportedOperationException("This should be done by JetIconProvider")
 
@@ -254,7 +253,7 @@ open class KtLightClassForFacadeImpl constructor(
 
     companion object {
 
-        fun createForFacadeNoCache(fqName: FqName, searchScope: GlobalSearchScope, project: Project): KtLightClassForFacadeImpl? {
+        fun createForFacadeNoCache(fqName: FqName, searchScope: GlobalSearchScope, project: Project): KtLightClassForFacade? {
 
             val sources = KotlinAsJavaSupport.getInstance(project).findFilesForFacade(fqName, searchScope)
                 .filterNot { it.isCompiled }
@@ -278,7 +277,7 @@ open class KtLightClassForFacadeImpl constructor(
             manager: PsiManager,
             facadeClassFqName: FqName,
             searchScope: GlobalSearchScope
-        ): KtLightClassForFacadeImpl? {
+        ): KtLightClassForFacade? {
             return FacadeCache.getInstance(manager.project)[facadeClassFqName, searchScope]
         }
 
@@ -286,7 +285,7 @@ open class KtLightClassForFacadeImpl constructor(
             manager: PsiManager,
             facadeClassFqName: FqName,
             file: KtFile
-        ): KtLightClassForFacadeImpl {
+        ): KtLightClassForFacade {
             // TODO: refactor, using cached value doesn't make sense for this case
             val cachedValue = CachedValuesManager.getManager(manager.project).createCachedValue(
                 LightClassDataProviderForFileFacade.ByFile(manager.project, facadeClassFqName, file), false

compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/KtLightClassForLocalDeclaration.kt

@@ -41,8 +41,8 @@ open class KtLightClassForLocalDeclaration(
 
                 var createWrapper = forceMethodWrapping
                 // Use PsiClass wrapper instead of package light class to avoid names like "FooPackage" in Type Hierarchy and related views
-                if (containingClass is KtLightClassForFacadeImpl) {
-                    containingClass = object : LightClass(containingClass as KtLightClassForFacadeImpl, KotlinLanguage.INSTANCE) {
+                if (containingClass is KtLightClassForFacade) {
+                    containingClass = object : LightClass(containingClass as KtLightClassForFacade, KotlinLanguage.INSTANCE) {
                         override fun getName(): String? = currentFileName
                     }
                     createWrapper = true

compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/ultraKtLightClassForFacade.kt

@@ -147,6 +147,6 @@ class KtUltraLightClassForFacade(
 
     override fun getOwnMethods() = _ownMethods
 
-    override fun copy(): KtLightClassForFacadeImpl =
+    override fun copy(): KtLightClassForFacade =
         KtUltraLightClassForFacade(manager, facadeClassFqName, lightClassDataCache, files, filesWithSupports)
 }

compiler/light-classes/src/org/jetbrains/kotlin/asJava/elements/FakeFileForLightClass.kt

@@ -35,7 +35,7 @@ import com.intellij.psi.util.PsiUtil
 import com.intellij.reference.SoftReference
 import com.intellij.util.AstLoadingFilter
 import org.jetbrains.kotlin.asJava.classes.KtLightClass
-import org.jetbrains.kotlin.asJava.classes.KtLightClassForFacadeImpl
+import org.jetbrains.kotlin.asJava.classes.KtLightClassForFacade
 import org.jetbrains.kotlin.asJava.classes.KtLightClassForSourceDeclaration
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.KtFile
@@ -127,7 +127,7 @@ open class FakeFileForLightClass(
     override fun isEquivalentTo(another: PsiElement?) = this == another
 
     override fun setPackageName(packageName: String) {
-        if (lightClass() is KtLightClassForFacadeImpl) {
+        if (lightClass() is KtLightClassForFacade) {
             ktFile.packageDirective?.fqName = FqName(packageName)
         } else {
             super.setPackageName(packageName)

compiler/light-classes/src/org/jetbrains/kotlin/asJava/lightClassUtils.kt

@@ -56,7 +56,7 @@ fun KtClassOrObject.toFakeLightClass(): KtFakeLightClass = KotlinAsJavaSupport.g
 fun KtFile.findFacadeClass(): KtLightClass? {
     return KotlinAsJavaSupport.getInstance(project)
             .getFacadeClassesInPackage(packageFqName, this.useScope as? GlobalSearchScope ?: GlobalSearchScope.projectScope(project))
-            .firstOrNull { it is KtLightClassForFacadeImpl && this in it.files } as? KtLightClass
+            .firstOrNull { it is KtLightClassForFacade && this in it.files } as? KtLightClass
 }
 
 fun KtScript.toLightClass(): KtLightClass? = KotlinAsJavaSupport.getInstance(project).getLightClassForScript(this)