181: FakeFileForLightClass made return "virtualFile" from "ktFile"

compiler/light-classes/src/org/jetbrains/kotlin/asJava/elements/FakeFileForLightClass.kt.181

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.asJava.elements
 
+import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.pom.java.LanguageLevel
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiElementVisitor
@@ -33,6 +34,10 @@ open class FakeFileForLightClass(
         private val stub: () -> PsiClassHolderFileStub<*>,
         private val packageFqName: FqName = ktFile.packageFqName
 ) : ClsFileImpl(ktFile.viewProvider) {
+
+    override fun getVirtualFile(): VirtualFile =
+        ktFile.virtualFile ?: ktFile.originalFile.virtualFile ?: super.getVirtualFile()
+
     override fun getPackageName() = packageFqName.asString()
 
     override fun getStub() = stub()

idea/tests/org/jetbrains/kotlin/asJava/KtFileLightClassTest.kt.181

@@ -17,9 +17,13 @@
 package org.jetbrains.kotlin.asJava
 
 import com.intellij.injected.editor.EditorWindow
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiFile
 import com.intellij.psi.search.GlobalSearchScope
 import com.intellij.testFramework.LightProjectDescriptor
-import org.intellij.lang.annotations.Language
+import junit.framework.TestCase
+import org.jetbrains.kotlin.asJava.elements.KtLightElement
+import org.jetbrains.kotlin.idea.core.copied
 import org.jetbrains.kotlin.idea.test.KotlinLightCodeInsightFixtureTestCase
 import org.jetbrains.kotlin.idea.test.KotlinLightProjectDescriptor
 import org.jetbrains.kotlin.idea.test.PluginTestCaseBase
@@ -92,4 +96,40 @@ class KtFileLightClassTest : KotlinLightCodeInsightFixtureTestCase() {
         assertEquals("Injected class should be `A`", "A", (injectedFile as KtFile).classes.single().name)
     }
 
+
+    fun testSameVirtualFileForLightElement() {
+
+        val psiFile = myFixture.addFileToProject(
+            "pkg/AnnotatedClass.kt", """
+            package pkg
+
+            class AnnotatedClass {
+                    @Deprecated("a")
+                    fun bar(param: String) = null
+            }
+        """.trimIndent()
+        )
+
+        fun lightElement(file: PsiFile): PsiElement = (file as KtFile).classes.single()
+            .methods.first { it.name == "bar" }
+            .annotations.first { it.qualifiedName == "kotlin.Deprecated" }.also {
+            // Otherwise following asserts have no sense
+            TestCase.assertTrue("psi element should be light ", it is KtLightElement<*, *>)
+        }
+
+
+        val copied = psiFile.copied()
+        TestCase.assertNull("virtual file for copy should be null", copied.virtualFile)
+        TestCase.assertNotNull("psi element in copy", lightElement(copied))
+        TestCase.assertSame("copy.originalFile should be psiFile", copied.originalFile, psiFile)
+
+        // virtual files should be the same for light and non-light element,
+        // otherwise we will not be able to find proper module by file from light element
+        TestCase.assertSame(
+            "virtualFiles of element and file itself should be the same",
+            lightElement(copied).containingFile.originalFile.virtualFile,
+            copied.originalFile.virtualFile
+        )
+    }
+
 }