FIR deserializer: use annotation info from enclosing class for companion object

compiler/fir/analysis-tests/testData/loadCompiledKotlin/annotations/classMembers/ClassObjectPropertyField.txt

@@ -7,7 +7,7 @@ public final class Class : R|kotlin/Any| {
     public constructor(): R|test/Class|
 
     public final companion object Companion : R|kotlin/Any| {
-        public final var property: R|kotlin/Int|
+        @FIELD:R|test/Anno|() public final var property: R|kotlin/Int|
             public get(): R|kotlin/Int|
             public set(value: R|kotlin/Int|): R|kotlin/Unit|
 

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/deserialization/JvmBinaryAnnotationDeserializer.kt

@@ -30,12 +30,16 @@ class JvmBinaryAnnotationDeserializer(
     kotlinBinaryClass: KotlinJvmBinaryClass,
     byteContent: ByteArray?
 ) : AbstractAnnotationDeserializer(session) {
-    // TODO: In order to properly load annotations on fields inside a companion object,
-    //  we need binary classes for both the companion class and the enclosing class.
     private val annotationInfo by lazy(LazyThreadSafetyMode.PUBLICATION) {
         session.loadMemberAnnotations(kotlinBinaryClass, byteContent)
     }
 
+    override fun inheritAnnotationInfo(parent: AbstractAnnotationDeserializer) {
+        if (parent is JvmBinaryAnnotationDeserializer) {
+            annotationInfo.memberAnnotations.putAll(parent.annotationInfo.memberAnnotations)
+        }
+    }
+
     override fun loadTypeAnnotations(typeProto: ProtoBuf.Type, nameResolver: NameResolver): List<FirAnnotationCall> {
         val annotations = typeProto.getExtension(JvmProtoBuf.typeAnnotation).orEmpty()
         return annotations.map { deserializeAnnotation(it, nameResolver) }
@@ -244,7 +248,7 @@ class JvmBinaryAnnotationDeserializer(
 }
 
 // TODO: Rename this once property constants are recorded as well
-private data class MemberAnnotations(val memberAnnotations: Map<MemberSignature, MutableList<FirAnnotationCall>>)
+private data class MemberAnnotations(val memberAnnotations: MutableMap<MemberSignature, MutableList<FirAnnotationCall>>)
 
 // TODO: better to be in KotlinDeserializedJvmSymbolsProvider?
 private fun FirSession.loadMemberAnnotations(kotlinBinaryClass: KotlinJvmBinaryClass, byteContent: ByteArray?): MemberAnnotations {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/deserialization/AbstractAnnotationDeserializer.kt

@@ -42,6 +42,9 @@ abstract class AbstractAnnotationDeserializer(
 ) {
     protected val protocol = BuiltInSerializerProtocol
 
+    open fun inheritAnnotationInfo(parent: AbstractAnnotationDeserializer) {
+    }
+
     enum class CallableKind {
         PROPERTY,
         PROPERTY_GETTER,

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/deserialization/ClassDeserialization.kt

@@ -89,6 +89,11 @@ fun deserializeClassToSymbol(
             FirConstDeserializer(session, (containerSource as? KotlinJvmBinarySourceElement)?.binaryClass),
             containerSource
         )
+    if (status.isCompanion) {
+        parentContext?.let {
+            context.annotationDeserializer.inheritAnnotationInfo(it.annotationDeserializer)
+        }
+    }
     buildRegularClass {
         this.session = session
         origin = FirDeclarationOrigin.Library