Store outer class in ProtoContainer instead of only its kind

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/kotlin/AbstractBinaryClassAnnotationAndConstantLoader.kt

@@ -215,10 +215,12 @@ abstract class AbstractBinaryClassAnnotationAndConstantLoader<A : Any, C : Any,
                 return kotlinClassFinder.findKotlinClass(implClassName)
             }
 
-            if (field && container.kind == ProtoBuf.Class.Kind.COMPANION_OBJECT &&
+            if (field && container.kind == ProtoBuf.Class.Kind.COMPANION_OBJECT) {
-                (container.outerClassKind == ClassKind.CLASS || container.outerClassKind == ClassKind.ENUM_CLASS)) {
+                val outerClass = container.outerClass
-                // Backing fields of properties of a companion object in a class are generated in the outer class
+                if (outerClass != null && (outerClass.kind == ProtoBuf.Class.Kind.CLASS || outerClass.kind == ProtoBuf.Class.Kind.ENUM_CLASS)) {
-                return kotlinClassFinder.findKotlinClass(container.classId.outerClassId)
+                    // Backing fields of properties of a companion object in a class are generated in the outer class
+                    return outerClass.toBinaryClass()
+                }
             }
 
             return containerBinaryClass

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/ProtoContainer.kt

@@ -16,7 +16,6 @@
 
 package org.jetbrains.kotlin.serialization.deserialization
 
-import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.SourceElement
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
@@ -33,7 +32,7 @@ sealed class ProtoContainer(
             nameResolver: NameResolver,
             typeTable: TypeTable,
             source: SourceElement?,
-            val outerClassKind: ClassKind?
+            val outerClass: ProtoContainer.Class?
     ) : ProtoContainer(nameResolver, typeTable, source) {
         val classId: ClassId = nameResolver.getClassId(classProto.fqName)
 

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/descriptors/DeserializedClassDescriptor.kt

@@ -73,8 +73,9 @@ class DeserializedClassDescriptor(
     private val constructors = c.storageManager.createLazyValue { computeConstructors() }
     private val companionObjectDescriptor = c.storageManager.createNullableLazyValue { computeCompanionObjectDescriptor() }
 
-    internal val thisAsProtoContainer = ProtoContainer.Class(
+    internal val thisAsProtoContainer: ProtoContainer.Class = ProtoContainer.Class(
-            classProto, c.nameResolver, c.typeTable, sourceElement, (containingDeclaration as? ClassDescriptor)?.kind
+            classProto, c.nameResolver, c.typeTable, sourceElement,
+            (containingDeclaration as? DeserializedClassDescriptor)?.thisAsProtoContainer
     )
 
     private val annotations =

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/stubBuilder/ClassClsStubBuilder.kt

@@ -37,7 +37,10 @@ import org.jetbrains.kotlin.psi.stubs.impl.KotlinObjectStubImpl
 import org.jetbrains.kotlin.psi.stubs.impl.KotlinPlaceHolderStubImpl
 import org.jetbrains.kotlin.serialization.Flags
 import org.jetbrains.kotlin.serialization.ProtoBuf
-import org.jetbrains.kotlin.serialization.deserialization.*
+import org.jetbrains.kotlin.serialization.deserialization.NameResolver
+import org.jetbrains.kotlin.serialization.deserialization.ProtoContainer
+import org.jetbrains.kotlin.serialization.deserialization.TypeTable
+import org.jetbrains.kotlin.serialization.deserialization.supertypes
 
 fun createClassStub(
         parent: StubElement<out PsiElement>,
@@ -58,9 +61,14 @@ private class ClassClsStubBuilder(
         private val source: SourceElement?,
         private val outerContext: ClsStubBuilderContext
 ) {
-    private val classKind = Flags.CLASS_KIND[classProto.flags]
+    private val thisAsProtoContainer = ProtoContainer.Class(
-    private val c = outerContext.child(classProto.typeParameterList, classKind, classId.shortClassName, nameResolver,
+            classProto, nameResolver, TypeTable(classProto.typeTable), source, outerContext.protoContainer
-                                       TypeTable(classProto.typeTable))
+    )
+    private val classKind = thisAsProtoContainer.kind
+
+    private val c = outerContext.child(
+            classProto.typeParameterList, classId.shortClassName, nameResolver, thisAsProtoContainer.typeTable, thisAsProtoContainer
+    )
     private val typeStubBuilder = TypeClsStubBuilder(c)
     private val supertypeIds = run {
         val supertypeIds = classProto.supertypes(c.typeTable).map { c.nameResolver.getClassId(it.className) }
@@ -76,10 +84,6 @@ private class ClassClsStubBuilder(
     private val companionObjectName =
             if (classProto.hasCompanionObjectName()) c.nameResolver.getName(classProto.companionObjectName) else null
 
-    private val thisAsProtoContainer = ProtoContainer.Class(
-            classProto, c.nameResolver, c.typeTable, source, outerContext.classKind?.let { Deserialization.classKind(it) }
-    )
-
     private val classOrObjectStub = createClassOrObjectStubAndModifierListStub()
 
     fun build() {

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/stubBuilder/ClsStubBuilderContext.kt

@@ -22,10 +22,7 @@ import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.serialization.ProtoBuf
-import org.jetbrains.kotlin.serialization.deserialization.AnnotationAndConstantLoader
+import org.jetbrains.kotlin.serialization.deserialization.*
-import org.jetbrains.kotlin.serialization.deserialization.ClassDataFinder
-import org.jetbrains.kotlin.serialization.deserialization.NameResolver
-import org.jetbrains.kotlin.serialization.deserialization.TypeTable
 
 data class ClassIdWithTarget(val classId: ClassId, val target: AnnotationUseSiteTarget?)
 
@@ -39,7 +36,7 @@ class ClsStubBuilderComponents(
             packageFqName: FqName,
             typeTable: TypeTable
     ): ClsStubBuilderContext {
-        return ClsStubBuilderContext(this, nameResolver, packageFqName, EmptyTypeParameters, typeTable, classKind = null)
+        return ClsStubBuilderContext(this, nameResolver, packageFqName, EmptyTypeParameters, typeTable, protoContainer = null)
     }
 }
 
@@ -70,15 +67,15 @@ class ClsStubBuilderContext(
         val containerFqName: FqName,
         val typeParameters: TypeParameters,
         val typeTable: TypeTable,
-        val classKind: ProtoBuf.Class.Kind?
+        val protoContainer: ProtoContainer.Class?
 )
 
 internal fun ClsStubBuilderContext.child(
         typeParameterList: List<ProtoBuf.TypeParameter>,
-        classKind: ProtoBuf.Class.Kind? = null,
         name: Name? = null,
         nameResolver: NameResolver = this.nameResolver,
-        typeTable: TypeTable = this.typeTable
+        typeTable: TypeTable = this.typeTable,
+        protoContainer: ProtoContainer.Class? = this.protoContainer
 ): ClsStubBuilderContext {
     return ClsStubBuilderContext(
             this.components,
@@ -86,6 +83,6 @@ internal fun ClsStubBuilderContext.child(
             if (name != null) this.containerFqName.child(name) else this.containerFqName,
             this.typeParameters.child(nameResolver, typeParameterList),
             typeTable,
-            classKind
+            protoContainer
     )
 }