K2: report DUPLICATE_CLASS_NAMES error in JVM backend

It was already reported in the K2+PSI mode, but not LT because
BuilderFactoryForDuplicateClassNameDiagnostics relied on PSI, and did
not do anything if PSI was missing.

No tests were added because it fixes the already existing test
`compiler/testData/cli/jvm/fileClassClashMultipleFiles` after the
project is migrated to 2.0.

 #KT-59586

compiler/backend/src/org/jetbrains/kotlin/codegen/state/BuilderFactoryForDuplicateClassNameDiagnostics.kt

@@ -18,34 +18,33 @@ package org.jetbrains.kotlin.codegen.state
 
 import org.jetbrains.kotlin.codegen.ClassBuilderFactory
 import org.jetbrains.kotlin.codegen.ClassNameCollectionClassBuilderFactory
-import org.jetbrains.kotlin.diagnostics.DiagnosticSink
 import org.jetbrains.kotlin.renderer.DescriptorRenderer
-import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmDeclarationOrigin
 import java.util.concurrent.ConcurrentHashMap
 
-
 class BuilderFactoryForDuplicateClassNameDiagnostics(
-        builderFactory: ClassBuilderFactory,
-        private val diagnostics: DiagnosticSink
+    builderFactory: ClassBuilderFactory,
+    private val state: GenerationState,
 ) : ClassNameCollectionClassBuilderFactory(builderFactory) {
 
     private val className = ConcurrentHashMap<String, JvmDeclarationOrigin>()
 
     override fun handleClashingNames(internalName: String, origin: JvmDeclarationOrigin) {
-        val another = className.getOrPut(internalName, { origin })
-        //workaround for inlined anonymous objects
-        if (origin.element != another.element) {
+        val another = className.getOrPut(internalName) { origin }
+        // Allow clashing classes if they are originated from the same source element. For example, this happens during inlining anonymous
+        // objects. In JVM IR, this also happens for anonymous classes in default arguments of tailrec functions, because default arguments
+        // are deep-copied (see JvmTailrecLowering).
+        if (origin.originalSourceElement != another.originalSourceElement) {
             reportError(internalName, origin, another)
         }
     }
 
     private fun reportError(internalName: String, vararg another: JvmDeclarationOrigin) {
-        val fromString = another.mapNotNull { it.descriptor }.
-                joinToString { DescriptorRenderer.ONLY_NAMES_WITH_SHORT_TYPES.render(it) }
+        val duplicateClasses =
+            another.mapNotNull { it.descriptor }.joinToString { DescriptorRenderer.ONLY_NAMES_WITH_SHORT_TYPES.render(it) }
 
-        another.mapNotNull { it.element }.forEach {
-            diagnostics.report(ErrorsJvm.DUPLICATE_CLASS_NAMES.on(it, internalName, fromString))
+        for (origin in another) {
+            state.reportDuplicateClassNameError(origin, internalName, duplicateClasses)
         }
     }
-}
+}

compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt

@@ -46,6 +46,7 @@ import org.jetbrains.kotlin.resolve.diagnostics.Diagnostics
 import org.jetbrains.kotlin.resolve.diagnostics.OnDemandSuppressCache
 import org.jetbrains.kotlin.resolve.jvm.JvmClassName
 import org.jetbrains.kotlin.resolve.jvm.JvmCompilerDeserializationConfiguration
+import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmDeclarationOrigin
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmDeclarationOriginKind.*
 import org.jetbrains.kotlin.serialization.deserialization.DeserializationConfiguration
@@ -291,6 +292,12 @@ class GenerationState private constructor(
 
     var multiFieldValueClassUnboxInfo: (ClassDescriptor) -> MultiFieldValueClassUnboxInfo? = { null }
 
+    var reportDuplicateClassNameError: (JvmDeclarationOrigin, String, String) -> Unit = { origin, internalName, duplicateClasses ->
+        origin.element?.let {
+            diagnostics.report(ErrorsJvm.DUPLICATE_CLASS_NAMES.on(it, internalName, duplicateClasses))
+        }
+    }
+
     val typeApproximator: TypeApproximator? =
         if (languageVersionSettings.supportsFeature(LanguageFeature.NewInference))
             TypeApproximator(module.builtIns, languageVersionSettings)
@@ -308,7 +315,7 @@ class GenerationState private constructor(
                 },
                 {
                     // In IR backend, we have more precise information about classes and methods we are going to generate,
-                    // and report signature conflict errors in JvmSignatureClashTracker.
+                    // and report signature conflict errors in JvmSignatureClashDetector.
                     if (isIrBackend)
                         it
                     else
@@ -318,7 +325,7 @@ class GenerationState private constructor(
                             shouldGenerate = { origin -> !shouldOnlyCollectSignatures(origin) },
                         ).apply { duplicateSignatureFactory = this }
                 },
-                { BuilderFactoryForDuplicateClassNameDiagnostics(it, diagnostics) },
+                { BuilderFactoryForDuplicateClassNameDiagnostics(it, this) },
                 {
                     configuration.get(JVMConfigurationKeys.DECLARATIONS_JSON_PATH)
                         ?.let { destination -> SignatureDumpingBuilderFactory(it, File(destination)) } ?: it

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/diagnostics/JvmBackendErrors.kt

@@ -39,6 +39,8 @@ object JvmBackendErrors {
 
     val NOT_ALL_MULTIFILE_CLASS_PARTS_ARE_JVM_SYNTHETIC by error0<PsiElement>()
 
+    val DUPLICATE_CLASS_NAMES by error2<PsiElement, String, String>()
+
     init {
         RootDiagnosticRendererFactory.registerFactory(KtDefaultJvmErrorMessages)
     }
@@ -78,5 +80,7 @@ object KtDefaultJvmErrorMessages : BaseDiagnosticRendererFactory() {
             JvmBackendErrors.NOT_ALL_MULTIFILE_CLASS_PARTS_ARE_JVM_SYNTHETIC,
             "All of multi-file class parts should be annotated with @JvmSynthetic if at least one of them is"
         )
+
+        map.put(JvmBackendErrors.DUPLICATE_CLASS_NAMES, "Duplicate JVM class name ''{0}'' generated from: {1}", STRING, STRING)
     }
 }

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/diagnostics/JvmDeclarationOrigin.kt

@@ -25,6 +25,11 @@ open class JvmDeclarationOrigin(
     val descriptor: DeclarationDescriptor?,
     val parametersForJvmOverload: List<KtParameter?>? = null
 ) {
+    // This property is used to get the original element in the sources, from which this declaration was generated.
+    // In the old JVM backend, it is just the PSI element. In JVM IR, it is the original IR element (before any deep copy).
+    open val originalSourceElement: Any?
+        get() = element
+
     override fun toString(): String =
         if (this == NO_ORIGIN) "NO_ORIGIN" else "origin=$originKind element=${element?.javaClass?.simpleName} descriptor=$descriptor"
 

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmBackendContext.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.backend.jvm.MemoizedMultiFieldValueClassReplacements
 import org.jetbrains.kotlin.backend.jvm.MemoizedMultiFieldValueClassReplacements.RemappedParameter.RegularMapping
 import org.jetbrains.kotlin.backend.jvm.caches.BridgeLoweringCache
 import org.jetbrains.kotlin.backend.jvm.caches.CollectionStubComputer
+import org.jetbrains.kotlin.backend.jvm.extensions.JvmIrDeclarationOrigin
 import org.jetbrains.kotlin.backend.jvm.mapping.IrTypeMapper
 import org.jetbrains.kotlin.backend.jvm.mapping.MethodSignatureMapper
 import org.jetbrains.kotlin.codegen.inline.SMAP
@@ -40,6 +41,7 @@ import org.jetbrains.kotlin.ir.types.defaultType
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.resolve.jvm.JvmClassName
+import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmBackendErrors
 import org.jetbrains.org.objectweb.asm.Type
 import java.util.concurrent.ConcurrentHashMap
 
@@ -205,6 +207,13 @@ class JvmBackendContext(
                 node.leaves.map { Triple(defaultTypeMapper.mapType(it.type), it.fullMethodName.asString(), it.fullFieldName.asString()) }
             GenerationState.MultiFieldValueClassUnboxInfo(leavesInfo)
         }
+
+        state.reportDuplicateClassNameError = { origin, internalName, duplicateClasses ->
+            val declaration = (origin as JvmIrDeclarationOrigin).declaration
+            if (declaration != null) {
+                ktDiagnosticReporter.at(declaration).report(JvmBackendErrors.DUPLICATE_CLASS_NAMES, internalName, duplicateClasses)
+            }
+        }
     }
 
     fun referenceClass(descriptor: ClassDescriptor): IrClassSymbol =

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/extensions/JvmIrDeclarationOrigin.kt

@@ -20,7 +20,10 @@ class JvmIrDeclarationOrigin(
     originKind: JvmDeclarationOriginKind,
     element: PsiElement?,
     val declaration: IrDeclaration?,
-) : JvmDeclarationOrigin(originKind, element, declaration?.toIrBasedDescriptor(), null)
+) : JvmDeclarationOrigin(originKind, element, declaration?.toIrBasedDescriptor(), null) {
+    override val originalSourceElement: Any?
+        get() = (declaration as? IrAttributeContainer)?.attributeOwnerId
+}
 
 val IrDeclaration.descriptorOrigin: JvmIrDeclarationOrigin
     get() {