diff --git a/redwood-protocol-compose/src/commonMain/kotlin/app/cash/redwood/protocol/compose/ProtocolWidgetChildren.kt b/redwood-protocol-compose/src/commonMain/kotlin/app/cash/redwood/protocol/compose/ProtocolWidgetChildren.kt
index 55c068fb7c..36ad28dfca 100644
--- a/redwood-protocol-compose/src/commonMain/kotlin/app/cash/redwood/protocol/compose/ProtocolWidgetChildren.kt
+++ b/redwood-protocol-compose/src/commonMain/kotlin/app/cash/redwood/protocol/compose/ProtocolWidgetChildren.kt
@@ -36,7 +36,7 @@ internal class ProtocolWidgetChildren(
 
   override fun remove(index: Int, count: Int) {
     val removingIds = ids.subList(index, index + count)
-    val removedIds = removingIds.toList()
+    val removedIds = removingIds.toTypedArray()
     removingIds.clear()
 
     for (removedId in removedIds) {
diff --git a/redwood-protocol-compose/src/commonTest/kotlin/app/cash/redwood/protocol/compose/GeneratedProtocolBridgeTest.kt b/redwood-protocol-compose/src/commonTest/kotlin/app/cash/redwood/protocol/compose/GeneratedProtocolBridgeTest.kt
index 1c03c772a1..29878df56a 100644
--- a/redwood-protocol-compose/src/commonTest/kotlin/app/cash/redwood/protocol/compose/GeneratedProtocolBridgeTest.kt
+++ b/redwood-protocol-compose/src/commonTest/kotlin/app/cash/redwood/protocol/compose/GeneratedProtocolBridgeTest.kt
@@ -76,7 +76,7 @@ class GeneratedProtocolBridgeTest {
       Create(Id(1), WidgetTag(4)),
       ModifierChange(
         Id(1),
-        listOf(
+        arrayOf(
           ModifierElement(
             ModifierTag(3),
             buildJsonObject {
@@ -106,7 +106,7 @@ class GeneratedProtocolBridgeTest {
       Create(Id(1), WidgetTag(4)),
       ModifierChange(
         Id(1),
-        listOf(
+        arrayOf(
           ModifierElement(
             ModifierTag(5),
             buildJsonObject {
@@ -135,7 +135,7 @@ class GeneratedProtocolBridgeTest {
       argument = it
     }
 
-    protocolWidget.sendEvent(Event(Id(1), EventTag(4), listOf(JsonPrimitive("PT10S"))))
+    protocolWidget.sendEvent(Event(Id(1), EventTag(4), arrayOf(JsonPrimitive("PT10S"))))
 
     assertThat(argument).isEqualTo(10.seconds)
   }
diff --git a/redwood-protocol-widget/src/commonMain/kotlin/app/cash/redwood/protocol/widget/ProtocolBridge.kt b/redwood-protocol-widget/src/commonMain/kotlin/app/cash/redwood/protocol/widget/ProtocolBridge.kt
index ac51de2f3b..16bf17ff35 100644
--- a/redwood-protocol-widget/src/commonMain/kotlin/app/cash/redwood/protocol/widget/ProtocolBridge.kt
+++ b/redwood-protocol-widget/src/commonMain/kotlin/app/cash/redwood/protocol/widget/ProtocolBridge.kt
@@ -123,8 +123,8 @@ public class ProtocolBridge<W : Any>(
 private class RootProtocolNode<W : Any>(
   private val children: Widget.Children<W>,
 ) : ProtocolNode<W>, Widget<W> {
-  override fun updateModifier(elements: List<ModifierElement>) {
-    throw AssertionError("unexpected: $elements")
+  override fun updateModifier(elements: Array<ModifierElement>) {
+    throw AssertionError("unexpected: ${elements.contentToString()}")
   }
 
   override fun apply(change: PropertyChange, eventSink: EventSink) {
diff --git a/redwood-protocol-widget/src/commonMain/kotlin/app/cash/redwood/protocol/widget/ProtocolNode.kt b/redwood-protocol-widget/src/commonMain/kotlin/app/cash/redwood/protocol/widget/ProtocolNode.kt
index cc0fe55f14..c88d88ae81 100644
--- a/redwood-protocol-widget/src/commonMain/kotlin/app/cash/redwood/protocol/widget/ProtocolNode.kt
+++ b/redwood-protocol-widget/src/commonMain/kotlin/app/cash/redwood/protocol/widget/ProtocolNode.kt
@@ -41,7 +41,7 @@ public interface ProtocolNode<W : Any> {
 
   public fun apply(change: PropertyChange, eventSink: EventSink)
 
-  public fun updateModifier(elements: List<ModifierElement>)
+  public fun updateModifier(elements: Array<ModifierElement>)
 
   /**
    * Return one of this node's children groups by its [tag].
diff --git a/redwood-protocol-widget/src/commonTest/kotlin/app/cash/redwood/protocol/widget/ProtocolBridgeTest.kt b/redwood-protocol-widget/src/commonTest/kotlin/app/cash/redwood/protocol/widget/ProtocolBridgeTest.kt
index 21bb540978..1aceb25ab8 100644
--- a/redwood-protocol-widget/src/commonTest/kotlin/app/cash/redwood/protocol/widget/ProtocolBridgeTest.kt
+++ b/redwood-protocol-widget/src/commonTest/kotlin/app/cash/redwood/protocol/widget/ProtocolBridgeTest.kt
@@ -118,7 +118,7 @@ class ProtocolBridgeTest {
           tag = ChildrenTag.Root,
           index = 0,
           count = 1,
-          removedIds = listOf(Id(1)),
+          removedIds = arrayOf(Id(1)),
         ),
       ),
     )
diff --git a/redwood-protocol-widget/src/commonTest/kotlin/app/cash/redwood/protocol/widget/ProtocolNodeFactoryTest.kt b/redwood-protocol-widget/src/commonTest/kotlin/app/cash/redwood/protocol/widget/ProtocolNodeFactoryTest.kt
index b3589d869c..4888905dbd 100644
--- a/redwood-protocol-widget/src/commonTest/kotlin/app/cash/redwood/protocol/widget/ProtocolNodeFactoryTest.kt
+++ b/redwood-protocol-widget/src/commonTest/kotlin/app/cash/redwood/protocol/widget/ProtocolNodeFactoryTest.kt
@@ -97,7 +97,7 @@ class ProtocolNodeFactoryTest {
     val textInput = factory.create(WidgetTag(5))!!
 
     textInput.updateModifier(
-      listOf(
+      arrayOf(
         ModifierElement(
           tag = ModifierTag(3),
           value = buildJsonObject {
@@ -132,7 +132,7 @@ class ProtocolNodeFactoryTest {
     val textInput = factory.create(WidgetTag(5))!!
 
     textInput.updateModifier(
-      listOf(
+      arrayOf(
         ModifierElement(
           tag = ModifierTag(5),
           value = buildJsonObject {
@@ -164,7 +164,7 @@ class ProtocolNodeFactoryTest {
 
     val t = assertFailsWith<IllegalArgumentException> {
       button.updateModifier(
-        listOf(
+        arrayOf(
           ModifierElement(
             tag = ModifierTag(345432),
             value = JsonObject(mapOf()),
@@ -197,7 +197,7 @@ class ProtocolNodeFactoryTest {
 
     val textInput = factory.create(WidgetTag(5))!!
     textInput.updateModifier(
-      listOf(
+      arrayOf(
         ModifierElement(
           tag = ModifierTag(345432),
           value = buildJsonArray {
@@ -342,7 +342,7 @@ class ProtocolNodeFactoryTest {
     recordingTextInput.onChangeCustomType!!.invoke(10.seconds)
 
     assertThat(eventSink.events.single())
-      .isEqualTo(Event(Id(1), EventTag(4), listOf(JsonPrimitive("PT10S"))))
+      .isEqualTo(Event(Id(1), EventTag(4), arrayOf(JsonPrimitive("PT10S"))))
   }
 
   class RecordingTextInput : TextInput<Nothing> {
diff --git a/redwood-protocol/src/commonMain/kotlin/app/cash/redwood/protocol/protocol.kt b/redwood-protocol/src/commonMain/kotlin/app/cash/redwood/protocol/protocol.kt
index ed57d7c873..4ec345ef9f 100644
--- a/redwood-protocol/src/commonMain/kotlin/app/cash/redwood/protocol/protocol.kt
+++ b/redwood-protocol/src/commonMain/kotlin/app/cash/redwood/protocol/protocol.kt
@@ -15,14 +15,21 @@
  */
 package app.cash.redwood.protocol
 
+import dev.drewhamilton.poko.ArrayContentBased
+import dev.drewhamilton.poko.ArrayContentSupport
 import dev.drewhamilton.poko.Poko
+import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import kotlinx.serialization.builtins.ArraySerializer
+import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.descriptors.buildClassSerialDescriptor
 import kotlinx.serialization.descriptors.element
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.encoding.decodeStructure
+import kotlinx.serialization.encoding.encodeStructure
 import kotlinx.serialization.json.JsonDecoder
 import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.JsonEncoder
@@ -32,16 +39,69 @@ import kotlinx.serialization.json.buildJsonArray
 import kotlinx.serialization.json.jsonArray
 import kotlinx.serialization.json.jsonPrimitive
 
-@Serializable
+@OptIn(ArrayContentSupport::class)
+@Serializable(EventSerializer::class)
 @Poko
 public class Event(
   /** Identifier for the widget from which this event originated. */
   public val id: Id,
   /** Identifies which event occurred on the widget with [id]. */
   public val tag: EventTag,
-  public val args: List<JsonElement> = emptyList(),
+  @ArrayContentBased public val args: Array<JsonElement> = emptyArray(),
 )
 
+private object EventSerializer : KSerializer<Event> {
+  private val argsSerializer: KSerializer<Array<JsonElement>> =
+    @OptIn(ExperimentalSerializationApi::class)
+    ArraySerializer(JsonElement.serializer())
+
+  override val descriptor: SerialDescriptor = buildClassSerialDescriptor(
+    serialName = "app.cash.redwood.protocol.Event",
+  ) {
+      element<Id>("id")
+      element<EventTag>("tag")
+      element(
+        elementName = "args",
+        descriptor = argsSerializer.descriptor,
+        isOptional = true,
+      )
+    }
+
+  override fun deserialize(decoder: Decoder): Event {
+    return decoder.decodeStructure(descriptor) {
+      var id: Id? = null
+      var tag: EventTag? = null
+      var args: Array<JsonElement> = emptyArray()
+
+      var nextIndex = decodeElementIndex(descriptor)
+      while (nextIndex >= 0) {
+        when (nextIndex) {
+          0 -> id = decodeSerializableElement(descriptor, 0, Id.serializer())
+          1 -> tag = decodeSerializableElement(descriptor, 1, EventTag.serializer())
+          2 -> args = decodeSerializableElement(descriptor, 2, argsSerializer)
+          else -> throw IllegalStateException("Invalid index $nextIndex")
+        }
+        nextIndex = decodeElementIndex(descriptor)
+      }
+      Event(
+        id = checkNotNull(id),
+        tag = checkNotNull(tag),
+        args = args,
+      )
+    }
+  }
+
+  override fun serialize(encoder: Encoder, value: Event) {
+    encoder.encodeStructure(descriptor) {
+      encodeSerializableElement(descriptor, 0, Id.serializer(), value.id)
+      encodeSerializableElement(descriptor, 1, EventTag.serializer(), value.tag)
+      if (value.args.isNotEmpty()) {
+        encodeSerializableElement(descriptor, 2, argsSerializer, value.args)
+      }
+    }
+  }
+}
+
 @Serializable
 public sealed interface Change {
   /** Identifier for the widget which is the subject of this change. */
@@ -68,12 +128,13 @@ public class PropertyChange(
   public val value: JsonElement = JsonNull,
 ) : ValueChange
 
+@OptIn(ArrayContentSupport::class)
 @Serializable
 @SerialName("modifier")
 @Poko
 public class ModifierChange(
   override val id: Id,
-  public val elements: List<ModifierElement> = emptyList(),
+  @ArrayContentBased public val elements: Array<ModifierElement> = emptyArray(),
 ) : ValueChange
 
 @Serializable(with = ModifierElementSerializer::class)
@@ -143,6 +204,7 @@ public sealed interface ChildrenChange : Change {
     public val count: Int,
   ) : ChildrenChange
 
+  @OptIn(ArrayContentSupport::class)
   @Serializable
   @SerialName("remove")
   @Poko
@@ -151,7 +213,7 @@ public sealed interface ChildrenChange : Change {
     override val tag: ChildrenTag,
     public val index: Int,
     public val count: Int,
-    public val removedIds: List<Id>,
+    @ArrayContentBased public val removedIds: Array<Id>,
   ) : ChildrenChange {
     init {
       require(count == removedIds.size) {
diff --git a/redwood-protocol/src/commonTest/kotlin/app/cash/redwood/protocol/ProtocolTest.kt b/redwood-protocol/src/commonTest/kotlin/app/cash/redwood/protocol/ProtocolTest.kt
index 878ac4e4db..37cef90122 100644
--- a/redwood-protocol/src/commonTest/kotlin/app/cash/redwood/protocol/ProtocolTest.kt
+++ b/redwood-protocol/src/commonTest/kotlin/app/cash/redwood/protocol/ProtocolTest.kt
@@ -41,13 +41,13 @@ class ProtocolTest {
   }
 
   @Test fun eventNonEmptyArgs() {
-    val model = Event(Id(1), EventTag(2), listOf(JsonPrimitive("Hello"), JsonPrimitive(2)))
+    val model = Event(Id(1), EventTag(2), arrayOf(JsonPrimitive("Hello"), JsonPrimitive(2)))
     val json = """{"id":1,"tag":2,"args":["Hello",2]}"""
     assertJsonRoundtrip(Event.serializer(), model, json)
   }
 
   @Test fun eventEmptyArgs() {
-    val model = Event(Id(1), EventTag(2), listOf())
+    val model = Event(Id(1), EventTag(2), arrayOf())
     val json = """{"id":1,"tag":2}"""
     assertJsonRoundtrip(Event.serializer(), model, json)
   }
@@ -57,10 +57,10 @@ class ProtocolTest {
       Create(Id(1), WidgetTag(2)),
       ChildrenChange.Add(Id(1), ChildrenTag(2), Id(3), 4),
       ChildrenChange.Move(Id(1), ChildrenTag(2), 3, 4, 5),
-      ChildrenChange.Remove(Id(1), ChildrenTag(2), 3, 4, listOf(Id(5), Id(6), Id(7), Id(8))),
+      ChildrenChange.Remove(Id(1), ChildrenTag(2), 3, 4, arrayOf(Id(5), Id(6), Id(7), Id(8))),
       ModifierChange(
         Id(1),
-        listOf(
+        arrayOf(
           ModifierElement(
             ModifierTag(1),
             buildJsonObject { },
@@ -100,7 +100,7 @@ class ProtocolTest {
 
   @Test fun removeCountMustMatchListSize() {
     val t = assertFailsWith<IllegalArgumentException> {
-      ChildrenChange.Remove(Id(1), ChildrenTag(2), 3, 4, listOf(Id(5), Id(6), Id(7)))
+      ChildrenChange.Remove(Id(1), ChildrenTag(2), 3, 4, arrayOf(Id(5), Id(6), Id(7)))
     }
     assertThat(t).hasMessage("Count 4 != Removed ID list size 3")
   }
diff --git a/redwood-protocol/src/commonTest/kotlin/app/cash/redwood/protocol/SnapshotChangeListTest.kt b/redwood-protocol/src/commonTest/kotlin/app/cash/redwood/protocol/SnapshotChangeListTest.kt
index 8bdcf34b2b..7c6c9050d4 100644
--- a/redwood-protocol/src/commonTest/kotlin/app/cash/redwood/protocol/SnapshotChangeListTest.kt
+++ b/redwood-protocol/src/commonTest/kotlin/app/cash/redwood/protocol/SnapshotChangeListTest.kt
@@ -31,7 +31,7 @@ class SnapshotChangeListTest {
     val expected = SnapshotChangeList(
       listOf(
         Create(Id(1), WidgetTag(1)),
-        ModifierChange(Id(1), emptyList()),
+        ModifierChange(Id(1), emptyArray()),
         PropertyChange(Id(1), PropertyTag(1), JsonPrimitive("Hello")),
         Add(Id.Root, ChildrenTag.Root, Id(1), 0),
       ),
@@ -58,11 +58,11 @@ class SnapshotChangeListTest {
       SnapshotChangeList(
         listOf(
           Create(Id(1), WidgetTag(1)),
-          ModifierChange(Id(1), emptyList()),
+          ModifierChange(Id(1), emptyArray()),
           Move(Id.Root, ChildrenTag.Root, 1, 2, 3),
           PropertyChange(Id(1), PropertyTag(1), JsonPrimitive("Hello")),
           Add(Id.Root, ChildrenTag.Root, Id(1), 0),
-          Remove(Id.Root, ChildrenTag.Root, 1, 2, listOf(Id(3), Id(4))),
+          Remove(Id.Root, ChildrenTag.Root, 1, 2, arrayOf(Id(3), Id(4))),
         ),
       )
     }.hasMessage(
diff --git a/redwood-testing/src/commonTest/kotlin/app/cash/redwood/testing/ViewTreesTest.kt b/redwood-testing/src/commonTest/kotlin/app/cash/redwood/testing/ViewTreesTest.kt
index 8804b42588..784f806e5a 100644
--- a/redwood-testing/src/commonTest/kotlin/app/cash/redwood/testing/ViewTreesTest.kt
+++ b/redwood-testing/src/commonTest/kotlin/app/cash/redwood/testing/ViewTreesTest.kt
@@ -69,26 +69,26 @@ class ViewTreesTest {
 
     val expected = listOf(
       Create(Id(1), WidgetTag(1)),
-      ModifierChange(Id(1), emptyList()),
+      ModifierChange(Id(1), emptyArray()),
       Create(Id(2), WidgetTag(1)),
-      ModifierChange(Id(2), emptyList()),
+      ModifierChange(Id(2), emptyArray()),
       Create(Id(3), WidgetTag(3)),
-      ModifierChange(Id(3), emptyList()),
+      ModifierChange(Id(3), emptyArray()),
       PropertyChange(Id(3), PropertyTag(1), JsonPrimitive("One Fish")),
       Add(Id(2), ChildrenTag(1), Id(3), 0),
       Create(Id(4), WidgetTag(3)),
-      ModifierChange(Id(4), emptyList()),
+      ModifierChange(Id(4), emptyArray()),
       PropertyChange(Id(4), PropertyTag(1), JsonPrimitive("Two Fish")),
       Add(Id(2), ChildrenTag(1), Id(4), 1),
       Add(Id(1), ChildrenTag(1), Id(2), 0),
       Create(Id(5), WidgetTag(1)),
-      ModifierChange(Id(5), emptyList()),
+      ModifierChange(Id(5), emptyArray()),
       Create(Id(6), WidgetTag(3)),
-      ModifierChange(Id(6), emptyList()),
+      ModifierChange(Id(6), emptyArray()),
       PropertyChange(Id(6), PropertyTag(1), JsonPrimitive("Red Fish")),
       Add(Id(5), ChildrenTag(1), Id(6), 0),
       Create(Id(7), WidgetTag(3)),
-      ModifierChange(Id(7), emptyList()),
+      ModifierChange(Id(7), emptyArray()),
       PropertyChange(Id(7), PropertyTag(1), JsonPrimitive("Blue Fish")),
       Add(Id(5), ChildrenTag(1), Id(7), 1),
       Add(Id(1), ChildrenTag(1), Id(5), 1),
diff --git a/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/composeProtocolGeneration.kt b/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/composeProtocolGeneration.kt
index e3d49badb9..d92a2f2475 100644
--- a/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/composeProtocolGeneration.kt
+++ b/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/composeProtocolGeneration.kt
@@ -21,6 +21,7 @@ import app.cash.redwood.tooling.schema.ProtocolWidget
 import app.cash.redwood.tooling.schema.ProtocolWidget.ProtocolChildren
 import app.cash.redwood.tooling.schema.ProtocolWidget.ProtocolEvent
 import app.cash.redwood.tooling.schema.ProtocolWidget.ProtocolProperty
+import com.squareup.kotlinpoet.ARRAY
 import com.squareup.kotlinpoet.AnnotationSpec
 import com.squareup.kotlinpoet.BOOLEAN
 import com.squareup.kotlinpoet.BYTE
@@ -704,7 +705,7 @@ internal fun generateComposeProtocolModifierSerialization(
         .addModifiers(INTERNAL)
         .receiver(Redwood.Modifier)
         .addParameter("json", KotlinxSerialization.Json)
-        .returns(LIST.parameterizedBy(Protocol.ModifierElement))
+        .returns(ARRAY.parameterizedBy(Protocol.ModifierElement))
         .beginControlFlow("return %M", Stdlib.buildList)
         .addStatement(
           "this@%L.forEach { element -> add(element.%M(json)) }",
@@ -712,6 +713,7 @@ internal fun generateComposeProtocolModifierSerialization(
           schema.modifierToProtocol,
         )
         .endControlFlow()
+        .addCode("⇥.toTypedArray()⇤")
         .build(),
     )
     .addFunction(
diff --git a/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/widgetProtocolGeneration.kt b/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/widgetProtocolGeneration.kt
index d169eb13bd..e144e60edc 100644
--- a/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/widgetProtocolGeneration.kt
+++ b/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/widgetProtocolGeneration.kt
@@ -21,6 +21,7 @@ import app.cash.redwood.tooling.schema.ProtocolWidget
 import app.cash.redwood.tooling.schema.ProtocolWidget.ProtocolChildren
 import app.cash.redwood.tooling.schema.ProtocolWidget.ProtocolEvent
 import app.cash.redwood.tooling.schema.ProtocolWidget.ProtocolProperty
+import com.squareup.kotlinpoet.ARRAY
 import com.squareup.kotlinpoet.AnnotationSpec
 import com.squareup.kotlinpoet.ClassName
 import com.squareup.kotlinpoet.CodeBlock
@@ -29,7 +30,6 @@ import com.squareup.kotlinpoet.FunSpec
 import com.squareup.kotlinpoet.KModifier.INTERNAL
 import com.squareup.kotlinpoet.KModifier.OVERRIDE
 import com.squareup.kotlinpoet.KModifier.PRIVATE
-import com.squareup.kotlinpoet.LIST
 import com.squareup.kotlinpoet.ParameterSpec
 import com.squareup.kotlinpoet.ParameterizedTypeName.Companion.parameterizedBy
 import com.squareup.kotlinpoet.PropertySpec
@@ -281,7 +281,7 @@ internal fun generateProtocolNode(
                         beginControlFlow("{ %L ->", trait.parameterTypes.indices.map { CodeBlock.of("arg$it") }.joinToCode())
                       }
                       addStatement(
-                        "eventSink.sendEvent(%T(change.id, %T(%L), listOf(%L)))",
+                        "eventSink.sendEvent(%T(change.id, %T(%L), arrayOf(%L)))",
                         Protocol.Event,
                         Protocol.EventTag,
                         trait.tag,
@@ -360,7 +360,7 @@ internal fun generateProtocolNode(
         .addFunction(
           FunSpec.builder("updateModifier")
             .addModifiers(OVERRIDE)
-            .addParameter("elements", LIST.parameterizedBy(Protocol.ModifierElement))
+            .addParameter("elements", ARRAY.parameterizedBy(Protocol.ModifierElement))
             .addStatement("widget.modifier = elements.%M(json, mismatchHandler)", host.toModifier)
             .addStatement("container?.onModifierUpdated()")
             .build(),
@@ -444,7 +444,7 @@ internal fun generateProtocolModifierImpls(
 private fun generateJsonArrayToModifier(schema: ProtocolSchema): FunSpec {
   return FunSpec.builder("toModifier")
     .addModifiers(INTERNAL)
-    .receiver(LIST.parameterizedBy(Protocol.ModifierElement))
+    .receiver(ARRAY.parameterizedBy(Protocol.ModifierElement))
     .addParameter("json", KotlinxSerialization.Json)
     .addParameter("mismatchHandler", WidgetProtocol.ProtocolMismatchHandler)
     .addStatement(