Simplify deserialization of annotations on backing/delegate fields

Instead of returning the list of targeted annotations in
loadCallableAnnotations, add two separate methods to load annotations on
the backing field and on the delegate field of the property

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/classFile/KotlinClsStubBuilder.kt

@@ -23,7 +23,6 @@ import com.intellij.psi.impl.compiled.ClassFileStubBuilder
 import com.intellij.psi.stubs.PsiFileStub
 import com.intellij.util.indexing.FileContent
 import org.jetbrains.kotlin.descriptors.SourceElement
-import org.jetbrains.kotlin.descriptors.annotations.AnnotationUseSiteTarget
 import org.jetbrains.kotlin.idea.caches.IDEKotlinBinaryClassCache
 import org.jetbrains.kotlin.idea.decompiler.stubBuilder.*
 import org.jetbrains.kotlin.load.kotlin.*
@@ -125,7 +124,7 @@ class AnnotationLoaderForClassFileStubBuilder(
         kotlinClassFinder: KotlinClassFinder,
         private val cachedFile: VirtualFile,
         private val cachedFileContent: ByteArray
-) : AbstractBinaryClassAnnotationAndConstantLoader<ClassId, Unit, ClassIdWithTarget>(LockBasedStorageManager.NO_LOCKS, kotlinClassFinder) {
+) : AbstractBinaryClassAnnotationAndConstantLoader<ClassId, Unit>(LockBasedStorageManager.NO_LOCKS, kotlinClassFinder) {
 
     override fun getCachedFileContent(kotlinClass: KotlinJvmBinaryClass): ByteArray? {
         if ((kotlinClass as? VirtualFileKotlinClass)?.file == cachedFile) {
@@ -147,13 +146,4 @@ class AnnotationLoaderForClassFileStubBuilder(
         result.add(annotationClassId)
         return null
     }
-
-    override fun loadPropertyAnnotations(
-            propertyAnnotations: List<ClassId>, fieldAnnotations: List<ClassId>, fieldUseSiteTarget: AnnotationUseSiteTarget
-    ): List<ClassIdWithTarget> {
-        return propertyAnnotations.map { ClassIdWithTarget(it, null) } +
-               fieldAnnotations.map { ClassIdWithTarget(it, fieldUseSiteTarget ) }
-    }
-
-    override fun transformAnnotations(annotations: List<ClassId>) = annotations.map { ClassIdWithTarget(it, null) }
 }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/common/AnnotationLoaderForStubBuilderImpl.kt

@@ -16,7 +16,6 @@
 
 package org.jetbrains.kotlin.idea.decompiler.common
 
-import org.jetbrains.kotlin.idea.decompiler.stubBuilder.ClassIdWithTarget
 import org.jetbrains.kotlin.metadata.ProtoBuf
 import org.jetbrains.kotlin.metadata.deserialization.NameResolver
 import org.jetbrains.kotlin.name.ClassId
@@ -30,7 +29,7 @@ import org.jetbrains.kotlin.types.KotlinType
 
 class AnnotationLoaderForStubBuilderImpl(
         private val protocol: SerializerExtensionProtocol
-) : AnnotationAndConstantLoader<ClassId, Unit, ClassIdWithTarget> {
+) : AnnotationAndConstantLoader<ClassId, Unit> {
 
     override fun loadClassAnnotations(container: ProtoContainer.Class): List<ClassId> =
          container.classProto.getExtension(protocol.classAnnotation).orEmpty().map { container.nameResolver.getClassId(it.id) }
@@ -39,18 +38,22 @@ class AnnotationLoaderForStubBuilderImpl(
             container: ProtoContainer,
             proto: MessageLite,
             kind: AnnotatedCallableKind
-    ): List<ClassIdWithTarget> {
+    ): List<ClassId> {
         val annotations = when (proto) {
             is ProtoBuf.Constructor -> proto.getExtension(protocol.constructorAnnotation)
             is ProtoBuf.Function -> proto.getExtension(protocol.functionAnnotation)
             is ProtoBuf.Property -> proto.getExtension(protocol.propertyAnnotation)
             else -> error("Unknown message: $proto")
         }.orEmpty()
-        return annotations.map {
-            ClassIdWithTarget(container.nameResolver.getClassId(it.id), null)
-        }
+        return annotations.map { container.nameResolver.getClassId(it.id) }
     }
 
+    override fun loadPropertyBackingFieldAnnotations(container: ProtoContainer, proto: ProtoBuf.Property): List<ClassId> =
+        emptyList()
+
+    override fun loadPropertyDelegateFieldAnnotations(container: ProtoContainer, proto: ProtoBuf.Property): List<ClassId> =
+        emptyList()
+
     override fun loadEnumEntryAnnotations(container: ProtoContainer, proto: ProtoBuf.EnumEntry): List<ClassId> =
             proto.getExtension(protocol.enumEntryAnnotation).orEmpty().map { container.nameResolver.getClassId(it.id) }
 

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

@@ -166,7 +166,7 @@ private class FunctionClsStubBuilder(
         val annotationIds = c.components.annotationLoader.loadCallableAnnotations(
                 protoContainer, functionProto, AnnotatedCallableKind.FUNCTION
         )
-        createTargetedAnnotationStubs(annotationIds, modifierListStubImpl)
+        createAnnotationStubs(annotationIds, modifierListStubImpl)
     }
 
     override fun doCreateCallableStub(parent: StubElement<out PsiElement>): StubElement<out PsiElement> {
@@ -219,10 +219,17 @@ private class PropertyClsStubBuilder(
                 listOf(VISIBILITY, LATEINIT, EXTERNAL_PROPERTY) + constModifier + modalityModifier
         )
 
-        val annotationIds = c.components.annotationLoader.loadCallableAnnotations(
-                protoContainer, propertyProto, AnnotatedCallableKind.PROPERTY
-        )
-        createTargetedAnnotationStubs(annotationIds, modifierListStubImpl)
+        val propertyAnnotations =
+            c.components.annotationLoader.loadCallableAnnotations(protoContainer, propertyProto, AnnotatedCallableKind.PROPERTY)
+        val backingFieldAnnotations =
+            c.components.annotationLoader.loadPropertyBackingFieldAnnotations(protoContainer, propertyProto)
+        val delegateFieldAnnotations =
+            c.components.annotationLoader.loadPropertyDelegateFieldAnnotations(protoContainer, propertyProto)
+        val allAnnotations =
+            propertyAnnotations.map { ClassIdWithTarget(it, null) } +
+                    backingFieldAnnotations.map { ClassIdWithTarget(it, AnnotationUseSiteTarget.FIELD) } +
+                    delegateFieldAnnotations.map { ClassIdWithTarget(it, AnnotationUseSiteTarget.PROPERTY_DELEGATE_FIELD) }
+        createTargetedAnnotationStubs(allAnnotations, modifierListStubImpl)
     }
 
     override fun doCreateCallableStub(parent: StubElement<out PsiElement>): StubElement<out PsiElement> {
@@ -268,7 +275,7 @@ private class ConstructorClsStubBuilder(
         val annotationIds = c.components.annotationLoader.loadCallableAnnotations(
                 protoContainer, constructorProto, AnnotatedCallableKind.FUNCTION
         )
-        createTargetedAnnotationStubs(annotationIds, modifierListStubImpl)
+        createAnnotationStubs(annotationIds, modifierListStubImpl)
     }
 
     override fun doCreateCallableStub(parent: StubElement<out PsiElement>): StubElement<out PsiElement> {

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

@@ -33,7 +33,7 @@ data class ClassIdWithTarget(val classId: ClassId, val target: AnnotationUseSite
 
 class ClsStubBuilderComponents(
         val classDataFinder: ClassDataFinder,
-        val annotationLoader: AnnotationAndConstantLoader<ClassId, Unit, ClassIdWithTarget>,
+        val annotationLoader: AnnotationAndConstantLoader<ClassId, Unit>,
         val virtualFileForDebug: VirtualFile
 ) {
     fun createContext(