Support array class literals in annotation serializer/deserializer

Note that this change brings an incompatibility: `Array<Foo>::class`
will be seen as `Foo::class` by the old deserializer. We consider this
OK because the compiler never had any logic that relied on reading class
literal arguments correctly (otherwise it wouldn't have worked because
it could only see `Array<*>::class` before this commit), and the support
of annotations on types in JVM reflection is only available in the
upcoming 1.3 release (KT-16795)

 #KT-22069 Fixed

compiler/serialization/src/org/jetbrains/kotlin/serialization/AnnotationSerializer.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.serialization
 
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationArgumentVisitor
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptor
@@ -99,11 +100,23 @@ class AnnotationSerializer(private val stringTable: DescriptorAwareStringTable)
             }
 
             override fun visitKClassValue(value: KClassValue, data: Unit) {
-                val descriptor = value.value.constructor.declarationDescriptor as? ClassDescriptor
-                ?: throw UnsupportedOperationException("Class literal annotation argument should be a class: $value")
+                var kotlinType = value.value
+                var arrayDimensions = 0
+                while (KotlinBuiltIns.isArray(kotlinType)) {
+                    // We only support invariant projections and non-null array element types, see KT-26568
+                    kotlinType = kotlinType.arguments.single().type
+                    arrayDimensions++
+                }
+
+                val descriptor = kotlinType.constructor.declarationDescriptor as? ClassDescriptor
+                    ?: throw UnsupportedOperationException("Class literal annotation argument should be a class: $value")
 
                 type = Type.CLASS
                 classId = stringTable.getFqNameIndex(descriptor)
+
+                if (arrayDimensions > 0) {
+                    arrayDimensionCount = arrayDimensions
+                }
             }
 
             override fun visitLongValue(value: LongValue, data: Unit) {