[ULC] Fix invalid positive inheritor for self checking

Fixed #KT-43824

Author: igoriakovlev

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

@@ -264,19 +264,20 @@ abstract class KtLightClassForSourceDeclaration(
     override fun isValid(): Boolean = classOrObject.isValid
 
     override fun isInheritor(baseClass: PsiClass, checkDeep: Boolean): Boolean {
+        if (manager.areElementsEquivalent(baseClass, this)) return false
         LightClassInheritanceHelper.getService(project).isInheritor(this, baseClass, checkDeep).ifSure { return it }
 
         val qualifiedName: String? = if (baseClass is KtLightClassForSourceDeclaration) {
-            val baseDescriptor = baseClass.getDescriptor()
-            if (baseDescriptor != null) DescriptorUtils.getFqName(baseDescriptor).asString() else null
+            baseClass.getDescriptor()?.let(DescriptorUtils::getFqName)?.asString()
         } else {
             baseClass.qualifiedName
         }
 
         val thisDescriptor = getDescriptor()
 
         return if (qualifiedName != null && thisDescriptor != null) {
-            checkSuperTypeByFQName(thisDescriptor, qualifiedName, checkDeep)
+            qualifiedName != DescriptorUtils.getFqName(thisDescriptor).asString() &&
+                    checkSuperTypeByFQName(thisDescriptor, qualifiedName, checkDeep)
         } else {
             InheritanceImplUtil.isInheritor(this, baseClass, checkDeep)
         }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/lightClasses/IdeLightClassInheritanceHelper.kt

@@ -36,6 +36,7 @@ class IdeLightClassInheritanceHelper : LightClassInheritanceHelper {
         checkDeep: Boolean
     ): ImpreciseResolveResult {
         if (baseClass.project.isInDumbMode()) return NO_MATCH
+        if (lightClass.manager.areElementsEquivalent(baseClass, lightClass)) return NO_MATCH
 
         val classOrObject = lightClass.kotlinOrigin ?: return UNSURE
         val entries = classOrObject.superTypeListEntries

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/lightClasses/KtFakeLightClass.kt

@@ -12,6 +12,7 @@ import com.intellij.psi.impl.PsiClassImplUtil
 import com.intellij.psi.impl.light.AbstractLightClass
 import com.intellij.psi.impl.light.LightMethod
 import com.intellij.util.IncorrectOperationException
+import org.jetbrains.kotlin.asJava.ImpreciseResolveResult
 import org.jetbrains.kotlin.asJava.classes.KtLightClass
 import org.jetbrains.kotlin.asJava.classes.LightClassInheritanceHelper
 import org.jetbrains.kotlin.asJava.elements.KtLightElement
@@ -48,11 +49,17 @@ class KtFakeLightClass(override val kotlinOrigin: KtClassOrObject) :
     override fun getUseScope() = kotlinOrigin.useScope
 
     override fun isInheritor(baseClass: PsiClass, checkDeep: Boolean): Boolean {
+        if (manager.areElementsEquivalent(baseClass, this)) return false
         LightClassInheritanceHelper.getService(project).isInheritor(this, baseClass, checkDeep).ifSure { return it }
 
         val baseKtClass = (baseClass as? KtLightClass)?.kotlinOrigin ?: return false
         val baseDescriptor = baseKtClass.resolveToDescriptorIfAny() ?: return false
         val thisDescriptor = kotlinOrigin.resolveToDescriptorIfAny() ?: return false
+
+        val thisFqName = DescriptorUtils.getFqName(thisDescriptor).asString()
+        val baseFqName = DescriptorUtils.getFqName(baseDescriptor).asString()
+        if (thisFqName == baseFqName) return false
+
         return if (checkDeep)
             DescriptorUtils.isSubclass(thisDescriptor, baseDescriptor)
         else

idea/tests/org/jetbrains/kotlin/asJava/KotlinLightClassInheritorTest.kt

@@ -38,12 +38,16 @@ class KotlinLightClassInheritorTest : KotlinLightCodeInsightFixtureTestCase() {
         doTestInheritorByText("abstract class A<T> : List<T>", "java.lang.Object", true)
     }
 
-    private fun doTestInheritorByText(text: String, superQName: String, checkDeep: Boolean) {
+    fun testClassOnSelfDeep() {
+        doTestInheritorByText("class A", "A", checkDeep = true, result = false)
+    }
+
+    private fun doTestInheritorByText(text: String, superQName: String, checkDeep: Boolean, result: Boolean = true) {
         val file = myFixture.configureByText("A.kt", text) as KtFile
         val jetClass = file.declarations.filterIsInstance<KtClass>().single()
         val psiClass = KotlinAsJavaSupport.getInstance(project).getLightClass(jetClass)!!
         val baseClass = JavaPsiFacade.getInstance(project).findClass(superQName, GlobalSearchScope.allScope(project))!!
-        Assert.assertTrue(psiClass.isInheritor(baseClass, checkDeep))
+        Assert.assertEquals(psiClass.isInheritor(baseClass, checkDeep), result)
     }
 
     override fun getProjectDescriptor(): LightProjectDescriptor = KotlinLightProjectDescriptor.INSTANCE