diff --git a/samples/containers/android/src/main/java/com/squareup/sample/container/overviewdetail/OverviewDetailConfig.kt b/samples/containers/android/src/main/java/com/squareup/sample/container/overviewdetail/OverviewDetailConfig.kt
index 4b83a5ee2..141424aa8 100644
--- a/samples/containers/android/src/main/java/com/squareup/sample/container/overviewdetail/OverviewDetailConfig.kt
+++ b/samples/containers/android/src/main/java/com/squareup/sample/container/overviewdetail/OverviewDetailConfig.kt
@@ -31,7 +31,7 @@ enum class OverviewDetailConfig {
   Single;
 
   @OptIn(WorkflowUiExperimentalApi::class)
-  companion object : ViewEnvironmentKey<OverviewDetailConfig>(OverviewDetailConfig::class) {
+  companion object : ViewEnvironmentKey<OverviewDetailConfig>() {
     override val default = None
   }
 }
diff --git a/workflow-ui/compose-tooling/src/androidTest/java/com/squareup/workflow1/ui/compose/tooling/LegacyPreviewViewFactoryTest.kt b/workflow-ui/compose-tooling/src/androidTest/java/com/squareup/workflow1/ui/compose/tooling/LegacyPreviewViewFactoryTest.kt
index 6338b6c94..0cb79e794 100644
--- a/workflow-ui/compose-tooling/src/androidTest/java/com/squareup/workflow1/ui/compose/tooling/LegacyPreviewViewFactoryTest.kt
+++ b/workflow-ui/compose-tooling/src/androidTest/java/com/squareup/workflow1/ui/compose/tooling/LegacyPreviewViewFactoryTest.kt
@@ -164,7 +164,7 @@ internal class LegacyPreviewViewFactoryTest {
     )
   }
 
-  object TestEnvironmentKey : ViewEnvironmentKey<String>(String::class) {
+  object TestEnvironmentKey : ViewEnvironmentKey<String>() {
     override val default: String get() = error("Not specified")
   }
 
diff --git a/workflow-ui/compose-tooling/src/androidTest/java/com/squareup/workflow1/ui/compose/tooling/PreviewViewFactoryTest.kt b/workflow-ui/compose-tooling/src/androidTest/java/com/squareup/workflow1/ui/compose/tooling/PreviewViewFactoryTest.kt
index bba768ca6..5a9012044 100644
--- a/workflow-ui/compose-tooling/src/androidTest/java/com/squareup/workflow1/ui/compose/tooling/PreviewViewFactoryTest.kt
+++ b/workflow-ui/compose-tooling/src/androidTest/java/com/squareup/workflow1/ui/compose/tooling/PreviewViewFactoryTest.kt
@@ -194,7 +194,7 @@ internal class PreviewViewFactoryTest {
     )
   }
 
-  object TestEnvironmentKey : ViewEnvironmentKey<String>(String::class) {
+  object TestEnvironmentKey : ViewEnvironmentKey<String>() {
     override val default: String get() = error("Not specified")
   }
 
diff --git a/workflow-ui/compose/src/androidTest/java/com/squareup/workflow1/ui/compose/ComposeViewFactoryTest.kt b/workflow-ui/compose/src/androidTest/java/com/squareup/workflow1/ui/compose/ComposeViewFactoryTest.kt
index 6f1aae60a..eaf1e0ef3 100644
--- a/workflow-ui/compose/src/androidTest/java/com/squareup/workflow1/ui/compose/ComposeViewFactoryTest.kt
+++ b/workflow-ui/compose/src/androidTest/java/com/squareup/workflow1/ui/compose/ComposeViewFactoryTest.kt
@@ -78,7 +78,7 @@ internal class ComposeViewFactoryTest {
   }
 
   @Test fun getsViewEnvironmentUpdates() {
-    val testEnvironmentKey = object : ViewEnvironmentKey<String>(String::class) {
+    val testEnvironmentKey = object : ViewEnvironmentKey<String>() {
       override val default: String get() = error("No default")
     }
 
diff --git a/workflow-ui/compose/src/androidTest/java/com/squareup/workflow1/ui/compose/LegacyComposeViewFactoryTest.kt b/workflow-ui/compose/src/androidTest/java/com/squareup/workflow1/ui/compose/LegacyComposeViewFactoryTest.kt
index 8ee54914f..68f7c865d 100644
--- a/workflow-ui/compose/src/androidTest/java/com/squareup/workflow1/ui/compose/LegacyComposeViewFactoryTest.kt
+++ b/workflow-ui/compose/src/androidTest/java/com/squareup/workflow1/ui/compose/LegacyComposeViewFactoryTest.kt
@@ -79,7 +79,7 @@ internal class LegacyComposeViewFactoryTest {
   }
 
   @Test fun getsViewEnvironmentUpdates() {
-    val testEnvironmentKey = object : ViewEnvironmentKey<String>(String::class) {
+    val testEnvironmentKey = object : ViewEnvironmentKey<String>() {
       override val default: String get() = error("No default")
     }
 
diff --git a/workflow-ui/core-android/api/core-android.api b/workflow-ui/core-android/api/core-android.api
index 2b6917385..d403a64cb 100644
--- a/workflow-ui/core-android/api/core-android.api
+++ b/workflow-ui/core-android/api/core-android.api
@@ -334,24 +334,6 @@ public final class com/squareup/workflow1/ui/container/BackButtonScreen : com/sq
 	public fun map (Lkotlin/jvm/functions/Function1;)Lcom/squareup/workflow1/ui/container/BackButtonScreen;
 }
 
-public final class com/squareup/workflow1/ui/container/BackStackConfig : java/lang/Enum {
-	public static final field Companion Lcom/squareup/workflow1/ui/container/BackStackConfig$Companion;
-	public static final field First Lcom/squareup/workflow1/ui/container/BackStackConfig;
-	public static final field None Lcom/squareup/workflow1/ui/container/BackStackConfig;
-	public static final field Other Lcom/squareup/workflow1/ui/container/BackStackConfig;
-	public static fun valueOf (Ljava/lang/String;)Lcom/squareup/workflow1/ui/container/BackStackConfig;
-	public static fun values ()[Lcom/squareup/workflow1/ui/container/BackStackConfig;
-}
-
-public final class com/squareup/workflow1/ui/container/BackStackConfig$Companion : com/squareup/workflow1/ui/ViewEnvironmentKey {
-	public fun getDefault ()Lcom/squareup/workflow1/ui/container/BackStackConfig;
-	public synthetic fun getDefault ()Ljava/lang/Object;
-}
-
-public final class com/squareup/workflow1/ui/container/BackStackConfigKt {
-	public static final fun plus (Lcom/squareup/workflow1/ui/ViewEnvironment;Lcom/squareup/workflow1/ui/container/BackStackConfig;)Lcom/squareup/workflow1/ui/ViewEnvironment;
-}
-
 public class com/squareup/workflow1/ui/container/BackStackContainer : android/widget/FrameLayout {
 	public fun <init> (Landroid/content/Context;)V
 	public fun <init> (Landroid/content/Context;Landroid/util/AttributeSet;)V
diff --git a/workflow-ui/core-android/src/androidTest/java/com/squareup/workflow1/ui/DecorativeViewFactoryTest.kt b/workflow-ui/core-android/src/androidTest/java/com/squareup/workflow1/ui/DecorativeViewFactoryTest.kt
index 841b80d0e..f1cfa27c0 100644
--- a/workflow-ui/core-android/src/androidTest/java/com/squareup/workflow1/ui/DecorativeViewFactoryTest.kt
+++ b/workflow-ui/core-android/src/androidTest/java/com/squareup/workflow1/ui/DecorativeViewFactoryTest.kt
@@ -30,7 +30,7 @@ internal class DecorativeViewFactoryTest {
       }
     }
 
-    val envString = object : ViewEnvironmentKey<String>(String::class) {
+    val envString = object : ViewEnvironmentKey<String>() {
       override val default: String get() = "Not set"
     }
 
@@ -120,7 +120,7 @@ internal class DecorativeViewFactoryTest {
       }
     }
 
-    val envString = object : ViewEnvironmentKey<String>(String::class) {
+    val envString = object : ViewEnvironmentKey<String>() {
       override val default: String get() = "Not set"
     }
 
diff --git a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/ScreenViewFactoryFinder.kt b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/ScreenViewFactoryFinder.kt
index aa1e021b6..c55902c68 100644
--- a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/ScreenViewFactoryFinder.kt
+++ b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/ScreenViewFactoryFinder.kt
@@ -85,9 +85,7 @@ public interface ScreenViewFactoryFinder {
       )
   }
 
-  public companion object : ViewEnvironmentKey<ScreenViewFactoryFinder>(
-    ScreenViewFactoryFinder::class
-  ) {
+  public companion object : ViewEnvironmentKey<ScreenViewFactoryFinder>() {
     override val default: ScreenViewFactoryFinder
       get() = object : ScreenViewFactoryFinder {}
   }
diff --git a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/AlertDialogThemeResId.kt b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/AlertDialogThemeResId.kt
index f450840e0..97b02ba0f 100644
--- a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/AlertDialogThemeResId.kt
+++ b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/AlertDialogThemeResId.kt
@@ -8,6 +8,6 @@ import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
  * for the `@StyleRes themeResId: Int` argument of `AlertDialog.Builder()`.
  */
 @WorkflowUiExperimentalApi
-public object AlertDialogThemeResId : ViewEnvironmentKey<Int>(type = Int::class) {
+public object AlertDialogThemeResId : ViewEnvironmentKey<Int>() {
   override val default: Int = 0
 }
diff --git a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/CoveredByModal.kt b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/CoveredByModal.kt
index d805a44d1..e0b9e2093 100644
--- a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/CoveredByModal.kt
+++ b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/CoveredByModal.kt
@@ -12,6 +12,6 @@ import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
  * https://stackoverflow.com/questions/2886407/dealing-with-rapid-tapping-on-buttons
  */
 @WorkflowUiExperimentalApi
-internal object CoveredByModal : ViewEnvironmentKey<Boolean>(type = Boolean::class) {
+internal object CoveredByModal : ViewEnvironmentKey<Boolean>() {
   override val default: Boolean = false
 }
diff --git a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/DialogCollator.kt b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/DialogCollator.kt
index 4f70d9803..3350b4dac 100644
--- a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/DialogCollator.kt
+++ b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/DialogCollator.kt
@@ -254,7 +254,7 @@ internal class DialogCollator {
       ")"
   }
 
-  companion object : ViewEnvironmentKey<DialogCollator>(DialogCollator::class) {
+  companion object : ViewEnvironmentKey<DialogCollator>() {
     override val default: DialogCollator
       get() = error("Call ViewEnvironment.establishDialogCollator first.")
   }
diff --git a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/OverlayArea.kt b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/OverlayArea.kt
index cbc95a013..47feb3965 100644
--- a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/OverlayArea.kt
+++ b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/OverlayArea.kt
@@ -16,7 +16,7 @@ import kotlinx.coroutines.flow.StateFlow
 internal class OverlayArea(
   val bounds: StateFlow<Rect>
 ) {
-  companion object : ViewEnvironmentKey<OverlayArea>(type = OverlayArea::class) {
+  companion object : ViewEnvironmentKey<OverlayArea>() {
     override val default: OverlayArea = OverlayArea(MutableStateFlow(Rect()))
   }
 }
diff --git a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/OverlayDialogFactoryFinder.kt b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/OverlayDialogFactoryFinder.kt
index 81e91a032..f2425bf4b 100644
--- a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/OverlayDialogFactoryFinder.kt
+++ b/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/OverlayDialogFactoryFinder.kt
@@ -36,9 +36,7 @@ public interface OverlayDialogFactoryFinder {
       )
   }
 
-  public companion object : ViewEnvironmentKey<OverlayDialogFactoryFinder>(
-    OverlayDialogFactoryFinder::class
-  ) {
+  public companion object : ViewEnvironmentKey<OverlayDialogFactoryFinder>() {
     override val default: OverlayDialogFactoryFinder = object : OverlayDialogFactoryFinder {}
   }
 }
diff --git a/workflow-ui/core-android/src/test/java/com/squareup/workflow1/ui/container/ScreenViewFactoryTestUtil.kt b/workflow-ui/core-android/src/test/java/com/squareup/workflow1/ui/container/ScreenViewFactoryTestUtil.kt
index 6ffb7718a..5039372ae 100644
--- a/workflow-ui/core-android/src/test/java/com/squareup/workflow1/ui/container/ScreenViewFactoryTestUtil.kt
+++ b/workflow-ui/core-android/src/test/java/com/squareup/workflow1/ui/container/ScreenViewFactoryTestUtil.kt
@@ -32,7 +32,7 @@ internal fun mockView(): View {
   }
 }
 
-internal object SomeEnvValue : ViewEnvironmentKey<String>(String::class) {
+internal object SomeEnvValue : ViewEnvironmentKey<String>() {
   override val default: String get() = error("Unset")
 }
 
diff --git a/workflow-ui/core-common/api/core-common.api b/workflow-ui/core-common/api/core-common.api
index 65670738d..b14bd88ec 100644
--- a/workflow-ui/core-common/api/core-common.api
+++ b/workflow-ui/core-common/api/core-common.api
@@ -99,12 +99,12 @@ public final class com/squareup/workflow1/ui/ViewEnvironment$Companion {
 }
 
 public abstract class com/squareup/workflow1/ui/ViewEnvironmentKey {
+	public fun <init> ()V
 	public fun <init> (Lkotlin/reflect/KClass;)V
 	public fun combine (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
 	public final fun equals (Ljava/lang/Object;)Z
 	public abstract fun getDefault ()Ljava/lang/Object;
 	public final fun hashCode ()I
-	public final fun toString ()Ljava/lang/String;
 }
 
 public abstract interface class com/squareup/workflow1/ui/ViewRegistry {
@@ -194,6 +194,24 @@ public final class com/squareup/workflow1/ui/container/AlertOverlay$Event$Cancel
 	public static final field INSTANCE Lcom/squareup/workflow1/ui/container/AlertOverlay$Event$Canceled;
 }
 
+public final class com/squareup/workflow1/ui/container/BackStackConfig : java/lang/Enum {
+	public static final field Companion Lcom/squareup/workflow1/ui/container/BackStackConfig$Companion;
+	public static final field First Lcom/squareup/workflow1/ui/container/BackStackConfig;
+	public static final field None Lcom/squareup/workflow1/ui/container/BackStackConfig;
+	public static final field Other Lcom/squareup/workflow1/ui/container/BackStackConfig;
+	public static fun valueOf (Ljava/lang/String;)Lcom/squareup/workflow1/ui/container/BackStackConfig;
+	public static fun values ()[Lcom/squareup/workflow1/ui/container/BackStackConfig;
+}
+
+public final class com/squareup/workflow1/ui/container/BackStackConfig$Companion : com/squareup/workflow1/ui/ViewEnvironmentKey {
+	public fun getDefault ()Lcom/squareup/workflow1/ui/container/BackStackConfig;
+	public synthetic fun getDefault ()Ljava/lang/Object;
+}
+
+public final class com/squareup/workflow1/ui/container/BackStackConfigKt {
+	public static final fun plus (Lcom/squareup/workflow1/ui/ViewEnvironment;Lcom/squareup/workflow1/ui/container/BackStackConfig;)Lcom/squareup/workflow1/ui/ViewEnvironment;
+}
+
 public final class com/squareup/workflow1/ui/container/BackStackScreen : com/squareup/workflow1/ui/Container, com/squareup/workflow1/ui/Screen {
 	public fun <init> (Lcom/squareup/workflow1/ui/Screen;Ljava/util/List;)V
 	public fun <init> (Lcom/squareup/workflow1/ui/Screen;[Lcom/squareup/workflow1/ui/Screen;)V
diff --git a/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/ViewEnvironment.kt b/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/ViewEnvironment.kt
index bb7d08492..3508f820d 100644
--- a/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/ViewEnvironment.kt
+++ b/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/ViewEnvironment.kt
@@ -62,13 +62,23 @@ constructor(
 }
 
 /**
- * Defines a value that can be provided by a [ViewEnvironment] map, specifying its [type]
- * and [default] value.
+ * Defines a value type [T] that can be provided by a [ViewEnvironment] map,
+ * and specifies its [default] value.
+ *
+ * It is hard to imagine a useful implementation of this that is not a Kotlin `object`.
+ * Preferred use is to have the `companion object` of [T] extend this class. See
+ * [BackStackConfig.Companion][com.squareup.workflow1.ui.container.BackStackConfig.Companion]
+ * for an example.
  */
 @WorkflowUiExperimentalApi
-public abstract class ViewEnvironmentKey<T : Any>(
-  private val type: KClass<T>
-) {
+public abstract class ViewEnvironmentKey<T : Any>() {
+  @Deprecated("Use no args constructor", ReplaceWith("ViewEnvironmentKey<T>()"))
+  public constructor(@Suppress("UNUSED_PARAMETER") type: KClass<T>) : this()
+
+  /**
+   * Defines the default value for this key. It is a grievous error for this value to be
+   * dynamic in any way.
+   */
   public abstract val default: T
 
   /**
@@ -80,15 +90,9 @@ public abstract class ViewEnvironmentKey<T : Any>(
     right: T
   ): T = right
 
-  final override fun equals(other: Any?): Boolean = when {
-    this === other -> true
-    other != null && this::class != other::class -> false
-    else -> type == (other as ViewEnvironmentKey<*>).type
+  final override fun equals(other: Any?): Boolean {
+    return this === other || (other != null && this::class == other::class)
   }
 
-  final override fun hashCode(): Int = type.hashCode()
-
-  final override fun toString(): String {
-    return "${this::class.simpleName}(${type.simpleName})"
-  }
+  final override fun hashCode(): Int = this::class.hashCode()
 }
diff --git a/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/ViewRegistry.kt b/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/ViewRegistry.kt
index d90d37ab0..d4566d084 100644
--- a/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/ViewRegistry.kt
+++ b/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/ViewRegistry.kt
@@ -81,7 +81,7 @@ public interface ViewRegistry {
     renderingType: KClass<out RenderingT>
   ): Entry<RenderingT>?
 
-  public companion object : ViewEnvironmentKey<ViewRegistry>(ViewRegistry::class) {
+  public companion object : ViewEnvironmentKey<ViewRegistry>() {
     override val default: ViewRegistry get() = ViewRegistry()
     override fun combine(
       left: ViewRegistry,
diff --git a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/BackStackConfig.kt b/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/container/BackStackConfig.kt
similarity index 88%
rename from workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/BackStackConfig.kt
rename to workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/container/BackStackConfig.kt
index 7fb5c2949..17c912aeb 100644
--- a/workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/container/BackStackConfig.kt
+++ b/workflow-ui/core-common/src/main/java/com/squareup/workflow1/ui/container/BackStackConfig.kt
@@ -7,13 +7,13 @@ import com.squareup.workflow1.ui.container.BackStackConfig.First
 import com.squareup.workflow1.ui.container.BackStackConfig.Other
 
 /**
- * Informs views whether they're children of a [BackStackContainer],
+ * Informs views whether they're children of a [BackStackScreen],
  * and if so whether they're the [first frame][First] or [not][Other].
  */
 @WorkflowUiExperimentalApi
 public enum class BackStackConfig {
   /**
-   * There is no [BackStackContainer] above here.
+   * There is no [BackStackScreen] above here.
    */
   None,
 
@@ -29,7 +29,7 @@ public enum class BackStackConfig {
    */
   Other;
 
-  public companion object : ViewEnvironmentKey<BackStackConfig>(BackStackConfig::class) {
+  public companion object : ViewEnvironmentKey<BackStackConfig>() {
     override val default: BackStackConfig = None
   }
 }
diff --git a/workflow-ui/core-common/src/test/java/com/squareup/workflow1/ui/ViewEnvironmentTest.kt b/workflow-ui/core-common/src/test/java/com/squareup/workflow1/ui/ViewEnvironmentTest.kt
index 063aee10f..6f8186445 100644
--- a/workflow-ui/core-common/src/test/java/com/squareup/workflow1/ui/ViewEnvironmentTest.kt
+++ b/workflow-ui/core-common/src/test/java/com/squareup/workflow1/ui/ViewEnvironmentTest.kt
@@ -6,11 +6,11 @@ import org.junit.Test
 
 @OptIn(WorkflowUiExperimentalApi::class)
 internal class ViewEnvironmentTest {
-  private object StringHint : ViewEnvironmentKey<String>(String::class) {
+  private object StringHint : ViewEnvironmentKey<String>() {
     override val default = ""
   }
 
-  private object OtherStringHint : ViewEnvironmentKey<String>(String::class) {
+  private object OtherStringHint : ViewEnvironmentKey<String>() {
     override val default = ""
   }
 
@@ -18,7 +18,7 @@ internal class ViewEnvironmentTest {
     val int: Int = -1,
     val string: String = ""
   ) {
-    companion object : ViewEnvironmentKey<DataHint>(DataHint::class) {
+    companion object : ViewEnvironmentKey<DataHint>() {
       override val default = DataHint()
     }
   }
@@ -101,7 +101,7 @@ internal class ViewEnvironmentTest {
   }
 
   @Test fun `honors combine`() {
-    val combiningHint = object : ViewEnvironmentKey<String>(String::class) {
+    val combiningHint = object : ViewEnvironmentKey<String>() {
       override val default: String
         get() = error("")
 
diff --git a/workflow-ui/core-common/src/test/java/com/squareup/workflow1/ui/container/EnvironmentScreenTest.kt b/workflow-ui/core-common/src/test/java/com/squareup/workflow1/ui/container/EnvironmentScreenTest.kt
index 406c3cd0f..f1fc9fdf6 100644
--- a/workflow-ui/core-common/src/test/java/com/squareup/workflow1/ui/container/EnvironmentScreenTest.kt
+++ b/workflow-ui/core-common/src/test/java/com/squareup/workflow1/ui/container/EnvironmentScreenTest.kt
@@ -19,7 +19,7 @@ internal class EnvironmentScreenTest {
   ) : ViewRegistry.Entry<T>
 
   private data class TestValue(val value: String) {
-    companion object : ViewEnvironmentKey<TestValue>(TestValue::class) {
+    companion object : ViewEnvironmentKey<TestValue>() {
       override val default: TestValue get() = error("Set a default")
     }
   }