From 4d211af56316b310bee243af574b66a96d741727 Mon Sep 17 00:00:00 2001
From: filip-sakel <51793967+filip-sakel@users.noreply.github.com>
Date: Mon, 8 Mar 2021 20:49:05 +0200
Subject: [PATCH] Add '_spi(TokamakCore)' to ideally internal public members.
 (#386)
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Adds `_spi(TokamakCore)` to the modules:
1. TokamakCore
2. TokamakDOM
3. TokamakGTK
4. TokamakStaticHTML

The attribute is applied to:
1. All `View` bodies in TokamakCore — either primitive or regular like `Color`
2. `ViewDeferredToRenderer` bodies
4. `ParentView` `children` members
5. `View` modifiers (such as  `_onMount(perform:)`)
6. Other members of types (like `Color._withScheme`, and `_AnyApp._launch`)

The attribute semantics (from my brief testing)
1. It can only be applied to `public` declarations
2. It ensures that every SPI declaration is exposed only by other SPI declarations (i.e. `@_spi(Module) public enum A {}; public var a: A` is illegal)
3. Regularly importing a library prohibits clients from accessing SPI declarations that are not protocol witnesses (with an error).
4. Regularly importing a library "discourages" clients from accessing SPI protocol witnesses by hiding them from the autocompletion suggestions (i.e. users can still access `body` of `Text`, but autocompletion hides it).
5. For a declaration marked with `@_spi(Module)`, a client has to write `@_spi(Module) import Library` in order to normally access such SPI declarations.

* Add '_spi(TokamakCore)' to ideally internal public members.

* Remove `_spi` attribute on '_ConditionalContent'.

* Remove spi from 'Path._PathBox', 'Font._Font', and '_TupleScene.body'.

* Remove spi from types.

* Remove trailing whitespace.

* Apply spi to 'View' modifiers.

* Add _spi imports.

* Introduce 'PrimitiveView'.

* Remove 'PrimitiveView' conformances outside of TokamakCore.

* Fix `PrimitiveView` default implementation.

* Remove "BubbleCore" references.
---
 Sources/TokamakCore/App/AppStorage.swift         |  1 +
 Sources/TokamakCore/App/Scenes/WindowGroup.swift |  1 +
 .../TokamakCore/App/Scenes/_SceneModifier.swift  |  1 +
 Sources/TokamakCore/App/_AnyApp.swift            |  6 ++++++
 Sources/TokamakCore/App/_AnyScene.swift          |  1 +
 .../Modifiers/LifecycleModifier.swift            |  2 ++
 .../TokamakCore/Preferences/PreferenceKey.swift  |  6 ------
 Sources/TokamakCore/Shapes/Shape.swift           |  6 +-----
 Sources/TokamakCore/State/TargetRef.swift        |  1 +
 Sources/TokamakCore/Styles/ButtonStyle.swift     |  5 +----
 .../TokamakCore/Styles/NavigationLinkStyle.swift |  1 +
 Sources/TokamakCore/Tokens/Color.swift           |  2 ++
 Sources/TokamakCore/Views/AnyView.swift          |  7 ++-----
 Sources/TokamakCore/Views/Buttons/Button.swift   |  8 +++-----
 Sources/TokamakCore/Views/Buttons/Link.swift     |  6 +-----
 .../Views/Containers/DisclosureGroup.swift       |  6 +-----
 .../TokamakCore/Views/Containers/ForEach.swift   |  8 +++-----
 Sources/TokamakCore/Views/Containers/Group.swift |  7 ++-----
 Sources/TokamakCore/Views/Containers/List.swift  |  1 +
 .../Views/Containers/OutlineGroup.swift          |  2 ++
 .../TokamakCore/Views/Containers/Section.swift   |  1 +
 .../TokamakCore/Views/Containers/TupleView.swift |  6 +-----
 Sources/TokamakCore/Views/Image.swift            |  6 +-----
 .../Views/Layout/GeometryReader.swift            |  6 +-----
 Sources/TokamakCore/Views/Layout/HStack.swift    |  7 ++-----
 Sources/TokamakCore/Views/Layout/LazyHGrid.swift |  6 +-----
 Sources/TokamakCore/Views/Layout/LazyVGrid.swift |  6 +-----
 .../TokamakCore/Views/Layout/ScrollView.swift    |  7 ++-----
 Sources/TokamakCore/Views/Layout/VStack.swift    |  7 ++-----
 Sources/TokamakCore/Views/Layout/ZStack.swift    |  7 ++-----
 .../Views/Navigation/NavigationLink.swift        |  8 +++-----
 .../Views/Navigation/NavigationView.swift        |  6 +-----
 Sources/TokamakCore/Views/Selectors/Picker.swift | 16 ++++++----------
 Sources/TokamakCore/Views/Selectors/Slider.swift |  7 ++-----
 Sources/TokamakCore/Views/Selectors/Toggle.swift |  2 ++
 Sources/TokamakCore/Views/Spacers/Divider.swift  |  6 ++----
 Sources/TokamakCore/Views/Spacers/Spacer.swift   |  6 +-----
 Sources/TokamakCore/Views/Text/SecureField.swift |  7 ++-----
 Sources/TokamakCore/Views/Text/Text.swift        |  6 +-----
 Sources/TokamakCore/Views/Text/TextEditor.swift  |  6 +-----
 Sources/TokamakCore/Views/Text/TextField.swift   |  7 ++-----
 Sources/TokamakCore/Views/View.swift             | 15 +++++++++++++--
 Sources/TokamakCore/Views/ViewBuilder.swift      | 12 ++----------
 Sources/TokamakDOM/DOMRef.swift                  |  2 +-
 Sources/TokamakDOM/DOMRenderer.swift             |  2 +-
 Sources/TokamakDOM/Styles/ButtonStyle.swift      |  1 +
 Sources/TokamakDOM/Views/Buttons/Button.swift    |  1 +
 .../Views/Containers/DisclosureGroup.swift       |  1 +
 Sources/TokamakDOM/Views/DynamicHTML.swift       |  2 ++
 .../TokamakDOM/Views/Layout/GeometryReader.swift |  3 ++-
 .../Views/Navigation/NavigationLink.swift        |  1 +
 Sources/TokamakDOM/Views/Selectors/Picker.swift  |  2 ++
 Sources/TokamakDOM/Views/Selectors/Slider.swift  |  1 +
 Sources/TokamakDOM/Views/Text/SecureField.swift  |  1 +
 Sources/TokamakDOM/Views/Text/TextEditor.swift   |  1 +
 Sources/TokamakDOM/Views/Text/TextField.swift    |  1 +
 .../TokamakGTK/Modifiers/WidgetModifier.swift    |  1 +
 Sources/TokamakGTK/Shapes/Shape.swift            |  1 +
 Sources/TokamakGTK/Tokens/BuiltinColors.swift    |  2 +-
 Sources/TokamakGTK/Views/List.swift              |  1 +
 Sources/TokamakGTK/Views/NavigationView.swift    |  2 ++
 Sources/TokamakGTK/Views/ScrollView.swift        |  1 +
 Sources/TokamakGTK/Views/Stack.swift             |  2 ++
 Sources/TokamakGTK/Views/TextField.swift         |  2 ++
 .../Modifiers/ModifiedContent.swift              |  1 +
 Sources/TokamakStaticHTML/Shapes/Path.swift      |  1 +
 .../TokamakStaticHTML/Shapes/_ShapeView.swift    |  1 +
 .../TokamakStaticHTML/Tokens/BuiltinColors.swift |  2 +-
 .../TokamakStaticHTML/Views/Buttons/Link.swift   |  1 +
 .../Views/Containers/List.swift                  |  2 +-
 Sources/TokamakStaticHTML/Views/HTML.swift       |  2 ++
 .../TokamakStaticHTML/Views/Images/Image.swift   |  1 +
 .../TokamakStaticHTML/Views/Layout/HStack.swift  |  1 +
 .../Views/Layout/LazyHGrid.swift                 |  1 +
 .../Views/Layout/LazyVGrid.swift                 |  1 +
 .../Views/Layout/ScrollView.swift                |  1 +
 .../TokamakStaticHTML/Views/Layout/VStack.swift  |  1 +
 .../TokamakStaticHTML/Views/Layout/ZStack.swift  |  1 +
 .../Views/Navigation/NavigationView.swift        |  1 +
 .../Views/Spacers/Divider.swift                  |  2 +-
 .../TokamakStaticHTML/Views/Spacers/Spacer.swift |  1 +
 Tests/TokamakTests/ReconcilerTests.swift         |  2 +-
 82 files changed, 131 insertions(+), 164 deletions(-)

diff --git a/Sources/TokamakCore/App/AppStorage.swift b/Sources/TokamakCore/App/AppStorage.swift
index eb3b0dfa4..04ded2519 100644
--- a/Sources/TokamakCore/App/AppStorage.swift
+++ b/Sources/TokamakCore/App/AppStorage.swift
@@ -173,6 +173,7 @@ struct DefaultAppStorageEnvironmentKey: EnvironmentKey {
 }
 
 public extension EnvironmentValues {
+  @_spi(TokamakCore)
   var _defaultAppStorage: _StorageProvider? {
     get {
       self[DefaultAppStorageEnvironmentKey.self]
diff --git a/Sources/TokamakCore/App/Scenes/WindowGroup.swift b/Sources/TokamakCore/App/Scenes/WindowGroup.swift
index f3e4192bd..cd2d5c12a 100644
--- a/Sources/TokamakCore/App/Scenes/WindowGroup.swift
+++ b/Sources/TokamakCore/App/Scenes/WindowGroup.swift
@@ -63,6 +63,7 @@ public struct WindowGroup<Content>: Scene, TitledScene where Content: View {
     self.content = content()
   }
 
+  @_spi(TokamakCore)
   public var body: Never {
     neverScene("WindowGroup")
   }
diff --git a/Sources/TokamakCore/App/Scenes/_SceneModifier.swift b/Sources/TokamakCore/App/Scenes/_SceneModifier.swift
index b9030669e..555c3598a 100644
--- a/Sources/TokamakCore/App/Scenes/_SceneModifier.swift
+++ b/Sources/TokamakCore/App/Scenes/_SceneModifier.swift
@@ -25,6 +25,7 @@ public struct _SceneModifier_Content<Modifier>: Scene where Modifier: _SceneModi
   public let modifier: Modifier
   public let scene: _AnyScene
 
+  @_spi(TokamakCore)
   public var body: Never {
     neverScene("_SceneModifier_Content")
   }
diff --git a/Sources/TokamakCore/App/_AnyApp.swift b/Sources/TokamakCore/App/_AnyApp.swift
index 488cf2f2a..94fef4112 100644
--- a/Sources/TokamakCore/App/_AnyApp.swift
+++ b/Sources/TokamakCore/App/_AnyApp.swift
@@ -31,26 +31,32 @@ public struct _AnyApp: App {
     bodyType = A.Body.self
   }
 
+  @_spi(TokamakCore)
   public var body: Never {
     neverScene("_AnyApp")
   }
 
+  @_spi(TokamakCore)
   public init() {
     fatalError("`_AnyApp` cannot be initialized without an underlying `App` type.")
   }
 
+  @_spi(TokamakCore)
   public static func _launch(_ app: Self, _ rootEnvironment: EnvironmentValues) {
     fatalError("`_AnyApp` cannot be launched. Access underlying `app` value.")
   }
 
+  @_spi(TokamakCore)
   public static func _setTitle(_ title: String) {
     fatalError("`title` cannot be set for `AnyApp`. Access underlying `app` value.")
   }
 
+  @_spi(TokamakCore)
   public var _phasePublisher: AnyPublisher<ScenePhase, Never> {
     fatalError("`_AnyApp` cannot monitor scenePhase. Access underlying `app` value.")
   }
 
+  @_spi(TokamakCore)
   public var _colorSchemePublisher: AnyPublisher<ColorScheme, Never> {
     fatalError("`_AnyApp` cannot monitor colorScheme. Access underlying `app` value.")
   }
diff --git a/Sources/TokamakCore/App/_AnyScene.swift b/Sources/TokamakCore/App/_AnyScene.swift
index 59156bdbb..0a48557ff 100644
--- a/Sources/TokamakCore/App/_AnyScene.swift
+++ b/Sources/TokamakCore/App/_AnyScene.swift
@@ -66,6 +66,7 @@ public struct _AnyScene: Scene {
     }
   }
 
+  @_spi(TokamakCore)
   public var body: Never {
     neverScene("_AnyScene")
   }
diff --git a/Sources/TokamakCore/Modifiers/LifecycleModifier.swift b/Sources/TokamakCore/Modifiers/LifecycleModifier.swift
index aeda09b2b..5653a550a 100644
--- a/Sources/TokamakCore/Modifiers/LifecycleModifier.swift
+++ b/Sources/TokamakCore/Modifiers/LifecycleModifier.swift
@@ -14,10 +14,12 @@
 
 // FIXME: these should have standalone implementations
 public extension View {
+  @_spi(TokamakCore)
   func _onMount(perform action: (() -> ())? = nil) -> some View {
     modifier(_AppearanceActionModifier(appear: action))
   }
 
+  @_spi(TokamakCore)
   func _onUnmount(perform action: (() -> ())? = nil) -> some View {
     modifier(_AppearanceActionModifier(disappear: action))
   }
diff --git a/Sources/TokamakCore/Preferences/PreferenceKey.swift b/Sources/TokamakCore/Preferences/PreferenceKey.swift
index 55962a2fb..d67845218 100644
--- a/Sources/TokamakCore/Preferences/PreferenceKey.swift
+++ b/Sources/TokamakCore/Preferences/PreferenceKey.swift
@@ -96,12 +96,6 @@ public protocol _PreferenceWritingModifierProtocol: ViewModifier
   func body(_ content: Self.Content, with preferenceStore: inout _PreferenceStore) -> AnyView
 }
 
-public extension _PreferenceWritingViewProtocol where Self: View {
-  var body: Never {
-    neverBody(String(describing: Self.self))
-  }
-}
-
 public extension _PreferenceWritingModifierProtocol {
   func body(content: Content) -> AnyView {
     content.view
diff --git a/Sources/TokamakCore/Shapes/Shape.swift b/Sources/TokamakCore/Shapes/Shape.swift
index 3f72340d0..214efdf51 100644
--- a/Sources/TokamakCore/Shapes/Shape.swift
+++ b/Sources/TokamakCore/Shapes/Shape.swift
@@ -46,7 +46,7 @@ public struct FillStyle: Equatable, ShapeStyle {
   }
 }
 
-public struct _ShapeView<Content, Style>: View where Content: Shape, Style: ShapeStyle {
+public struct _ShapeView<Content, Style>: PrimitiveView where Content: Shape, Style: ShapeStyle {
   @Environment(\.self) public var environment
   @Environment(\.foregroundColor) public var foregroundColor
   public var shape: Content
@@ -58,10 +58,6 @@ public struct _ShapeView<Content, Style>: View where Content: Shape, Style: Shap
     self.style = style
     self.fillStyle = fillStyle
   }
-
-  public var body: Never {
-    neverBody("_ShapeView")
-  }
 }
 
 public extension Shape {
diff --git a/Sources/TokamakCore/State/TargetRef.swift b/Sources/TokamakCore/State/TargetRef.swift
index 9b124a867..f333b1139 100644
--- a/Sources/TokamakCore/State/TargetRef.swift
+++ b/Sources/TokamakCore/State/TargetRef.swift
@@ -33,6 +33,7 @@ public struct _TargetRef<V: View, T>: View, TargetRefType {
 public extension View {
   /** Allows capturing target instance of aclosest descendant host view. The resulting instance
    is written to a given `binding`. */
+  @_spi(TokamakCore)
   func _targetRef<T: Target>(_ binding: Binding<T?>) -> _TargetRef<Self, T> {
     .init(binding: binding, view: self)
   }
diff --git a/Sources/TokamakCore/Styles/ButtonStyle.swift b/Sources/TokamakCore/Styles/ButtonStyle.swift
index feab28f70..d3826e9d8 100644
--- a/Sources/TokamakCore/Styles/ButtonStyle.swift
+++ b/Sources/TokamakCore/Styles/ButtonStyle.swift
@@ -15,11 +15,8 @@
 //  Created by Gene Z. Ragan on 07/22/2020.
 
 public struct ButtonStyleConfiguration {
-  public struct Label: View {
+  public struct Label: PrimitiveView {
     let content: AnyView
-    public var body: Never {
-      neverBody("ButtonStyleConfiguration.Label")
-    }
   }
 
   public let label: Label
diff --git a/Sources/TokamakCore/Styles/NavigationLinkStyle.swift b/Sources/TokamakCore/Styles/NavigationLinkStyle.swift
index aef322fdb..f26bac3b0 100644
--- a/Sources/TokamakCore/Styles/NavigationLinkStyle.swift
+++ b/Sources/TokamakCore/Styles/NavigationLinkStyle.swift
@@ -68,6 +68,7 @@ extension EnvironmentValues {
 }
 
 public extension View {
+  @_spi(TokamakCore)
   func _navigationLinkStyle<S: _NavigationLinkStyle>(_ style: S) -> some View {
     environment(\._navigationLinkStyle, _AnyNavigationLinkStyle(style))
   }
diff --git a/Sources/TokamakCore/Tokens/Color.swift b/Sources/TokamakCore/Tokens/Color.swift
index f0e942c02..f36dd689c 100644
--- a/Sources/TokamakCore/Tokens/Color.swift
+++ b/Sources/TokamakCore/Tokens/Color.swift
@@ -241,6 +241,7 @@ public struct Color: Hashable, Equatable {
   }
 
   /// Create a `Color` dependent on the current `ColorScheme`.
+  @_spi(TokamakCore)
   public static func _withScheme(_ resolver: @escaping (ColorScheme) -> Self) -> Self {
     .init(_EnvironmentDependentColorBox {
       resolver($0.colorScheme)
@@ -344,6 +345,7 @@ public extension Color {
 
 extension Color: ShapeStyle {}
 extension Color: View {
+  @_spi(TokamakCore)
   public var body: some View {
     _ShapeView(shape: Rectangle(), style: self)
   }
diff --git a/Sources/TokamakCore/Views/AnyView.swift b/Sources/TokamakCore/Views/AnyView.swift
index 13e5a9606..3d0cb6db3 100644
--- a/Sources/TokamakCore/Views/AnyView.swift
+++ b/Sources/TokamakCore/Views/AnyView.swift
@@ -16,7 +16,7 @@
 //
 
 /// A type-erased view.
-public struct AnyView: View {
+public struct AnyView: PrimitiveView {
   /// The type of the underlying `view`.
   let type: Any.Type
 
@@ -67,10 +67,6 @@ public struct AnyView: View {
       }
     }
   }
-
-  public var body: Never {
-    neverBody("AnyView")
-  }
 }
 
 public func mapAnyView<T, V>(_ anyView: AnyView, transform: (V) -> T) -> T? {
@@ -80,6 +76,7 @@ public func mapAnyView<T, V>(_ anyView: AnyView, transform: (V) -> T) -> T? {
 }
 
 extension AnyView: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (view as? ParentView)?.children ?? []
   }
diff --git a/Sources/TokamakCore/Views/Buttons/Button.swift b/Sources/TokamakCore/Views/Buttons/Button.swift
index eaf5136e8..f5800731a 100644
--- a/Sources/TokamakCore/Views/Buttons/Button.swift
+++ b/Sources/TokamakCore/Views/Buttons/Button.swift
@@ -42,12 +42,13 @@ public struct Button<Label>: View where Label: View {
     implementation = _Button(action: action, label: label())
   }
 
+  @_spi(TomkamakCore)
   public var body: some View {
     implementation
   }
 }
 
-public struct _Button<Label>: View where Label: View {
+public struct _Button<Label>: PrimitiveView where Label: View {
   public let label: Label
   public let action: () -> ()
   @State public var isPressed = false
@@ -57,10 +58,6 @@ public struct _Button<Label>: View where Label: View {
     self.label = label
     self.action = action
   }
-
-  public var body: Never {
-    neverBody("_Button")
-  }
 }
 
 public extension Button where Label == Text {
@@ -72,6 +69,7 @@ public extension Button where Label == Text {
 }
 
 extension Button: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (implementation.label as? GroupView)?.children ?? [AnyView(implementation.label)]
   }
diff --git a/Sources/TokamakCore/Views/Buttons/Link.swift b/Sources/TokamakCore/Views/Buttons/Link.swift
index 0d80d27f1..e652de063 100644
--- a/Sources/TokamakCore/Views/Buttons/Link.swift
+++ b/Sources/TokamakCore/Views/Buttons/Link.swift
@@ -17,17 +17,13 @@
 
 import struct Foundation.URL
 
-public struct Link<Label>: View where Label: View {
+public struct Link<Label>: PrimitiveView where Label: View {
   let destination: URL
   let label: Label
 
   public init(destination: URL, @ViewBuilder label: () -> Label) {
     (self.destination, self.label) = (destination, label())
   }
-
-  public var body: Never {
-    neverBody("Link")
-  }
 }
 
 public extension Link where Label == Text {
diff --git a/Sources/TokamakCore/Views/Containers/DisclosureGroup.swift b/Sources/TokamakCore/Views/Containers/DisclosureGroup.swift
index 4df73a3e2..fb8d9b9ef 100644
--- a/Sources/TokamakCore/Views/Containers/DisclosureGroup.swift
+++ b/Sources/TokamakCore/Views/Containers/DisclosureGroup.swift
@@ -15,7 +15,7 @@
 //  Created by Carson Katri on 7/3/20.
 //
 
-public struct DisclosureGroup<Label, Content>: View where Label: View, Content: View {
+public struct DisclosureGroup<Label, Content>: PrimitiveView where Label: View, Content: View {
   @State var isExpanded: Bool = false
   let isExpandedBinding: Binding<Bool>?
 
@@ -39,10 +39,6 @@ public struct DisclosureGroup<Label, Content>: View where Label: View, Content:
     self.label = label()
     self.content = content
   }
-
-  public var body: Never {
-    neverBody("DisclosureGroup")
-  }
 }
 
 public extension DisclosureGroup where Label == Text {
diff --git a/Sources/TokamakCore/Views/Containers/ForEach.swift b/Sources/TokamakCore/Views/Containers/ForEach.swift
index fa97cd58f..9b8b226d9 100644
--- a/Sources/TokamakCore/Views/Containers/ForEach.swift
+++ b/Sources/TokamakCore/Views/Containers/ForEach.swift
@@ -31,7 +31,8 @@ protocol ForEachProtocol: GroupView {
 ///         Text("\($0)")
 ///       }
 ///     }
-public struct ForEach<Data, ID, Content>: View where Data: RandomAccessCollection, ID: Hashable,
+public struct ForEach<Data, ID, Content>: PrimitiveView where Data: RandomAccessCollection,
+  ID: Hashable,
   Content: View
 {
   let data: Data
@@ -47,10 +48,6 @@ public struct ForEach<Data, ID, Content>: View where Data: RandomAccessCollectio
     self.id = id
     self.content = content
   }
-
-  public var body: Never {
-    neverBody("ForEach")
-  }
 }
 
 extension ForEach: ForEachProtocol where Data.Index == Int {
@@ -79,6 +76,7 @@ public extension ForEach where Data == Range<Int>, ID == Int {
 }
 
 extension ForEach: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     data.map { AnyView(IDView(content($0), id: $0[keyPath: id])) }
   }
diff --git a/Sources/TokamakCore/Views/Containers/Group.swift b/Sources/TokamakCore/Views/Containers/Group.swift
index 59fd18358..d174b075b 100644
--- a/Sources/TokamakCore/Views/Containers/Group.swift
+++ b/Sources/TokamakCore/Views/Containers/Group.swift
@@ -19,13 +19,10 @@ public struct Group<Content> {
   }
 }
 
-extension Group: View where Content: View {
-  public var body: Never {
-    neverBody("Group")
-  }
-}
+extension Group: PrimitiveView & View where Content: View {}
 
 extension Group: ParentView where Content: View {
+  @_spi(TokamakCore)
   public var children: [AnyView] { (content as? ParentView)?.children ?? [AnyView(content)] }
 }
 
diff --git a/Sources/TokamakCore/Views/Containers/List.swift b/Sources/TokamakCore/Views/Containers/List.swift
index e2f02e309..747268f06 100644
--- a/Sources/TokamakCore/Views/Containers/List.swift
+++ b/Sources/TokamakCore/Views/Containers/List.swift
@@ -78,6 +78,7 @@ public struct List<SelectionValue, Content>: View
     }
   }
 
+  @_spi(TokamakCore)
   public var body: some View {
     if let style = style as? ListStyleDeferredToRenderer {
       style.listBody(ScrollView {
diff --git a/Sources/TokamakCore/Views/Containers/OutlineGroup.swift b/Sources/TokamakCore/Views/Containers/OutlineGroup.swift
index 0c962f063..5975a13bb 100644
--- a/Sources/TokamakCore/Views/Containers/OutlineGroup.swift
+++ b/Sources/TokamakCore/Views/Containers/OutlineGroup.swift
@@ -86,6 +86,7 @@ public extension OutlineGroup where Parent: View,
 }
 
 extension OutlineGroup: View where Parent: View, Leaf: View, Subgroup: View {
+  @_spi(TokamakCore)
   public var body: some View {
     switch root {
     case let .collection(data):
@@ -124,6 +125,7 @@ extension OutlineGroup: View where Parent: View, Leaf: View, Subgroup: View {
 public struct OutlineSubgroupChildren: View {
   let children: () -> AnyView
 
+  @_spi(TokamakCore)
   public var body: some View {
     children()
   }
diff --git a/Sources/TokamakCore/Views/Containers/Section.swift b/Sources/TokamakCore/Views/Containers/Section.swift
index d07e9de41..4f5c2eba9 100644
--- a/Sources/TokamakCore/Views/Containers/Section.swift
+++ b/Sources/TokamakCore/Views/Containers/Section.swift
@@ -33,6 +33,7 @@ extension Section: View, SectionView where Parent: View, Content: View, Footer:
   }
 
   @ViewBuilder
+  @_spi(TokamakCore)
   public var body: TupleView<(Parent, Content, Footer)> {
     header
     content
diff --git a/Sources/TokamakCore/Views/Containers/TupleView.swift b/Sources/TokamakCore/Views/Containers/TupleView.swift
index 9a2af4f9b..0ff33e0ed 100644
--- a/Sources/TokamakCore/Views/Containers/TupleView.swift
+++ b/Sources/TokamakCore/Views/Containers/TupleView.swift
@@ -18,11 +18,7 @@
 /// A `View` created from a `Tuple` of `View` values.
 ///
 /// Mainly for use with `@ViewBuilder`.
-public struct TupleView<T>: View {
-  public var body: Never {
-    neverBody("TupleView")
-  }
-
+public struct TupleView<T>: PrimitiveView {
   public let value: T
 
   let _children: [AnyView]
diff --git a/Sources/TokamakCore/Views/Image.swift b/Sources/TokamakCore/Views/Image.swift
index 7f0345b7b..5b67abc45 100644
--- a/Sources/TokamakCore/Views/Image.swift
+++ b/Sources/TokamakCore/Views/Image.swift
@@ -17,7 +17,7 @@
 
 import Foundation
 
-public struct Image: View {
+public struct Image: PrimitiveView {
   let label: Text?
   let name: String
   let bundle: Bundle?
@@ -39,10 +39,6 @@ public struct Image: View {
     self.name = name
     self.bundle = bundle
   }
-
-  public var body: Never {
-    neverBody("Image")
-  }
 }
 
 /// This is a helper type that works around absence of "package private" access control in Swift
diff --git a/Sources/TokamakCore/Views/Layout/GeometryReader.swift b/Sources/TokamakCore/Views/Layout/GeometryReader.swift
index 010bb2371..49157eb09 100644
--- a/Sources/TokamakCore/Views/Layout/GeometryReader.swift
+++ b/Sources/TokamakCore/Views/Layout/GeometryReader.swift
@@ -40,13 +40,9 @@ public func makeProxy(from size: CGSize) -> GeometryProxy {
 //   public subscript<T>(anchor: Anchor<T>) -> T {}
 // }
 
-public struct GeometryReader<Content>: View where Content: View {
+public struct GeometryReader<Content>: PrimitiveView where Content: View {
   public let content: (GeometryProxy) -> Content
   public init(@ViewBuilder content: @escaping (GeometryProxy) -> Content) {
     self.content = content
   }
-
-  public var body: Never {
-    neverBody("GeometryReader")
-  }
 }
diff --git a/Sources/TokamakCore/Views/Layout/HStack.swift b/Sources/TokamakCore/Views/Layout/HStack.swift
index 720ec3420..70d1089e3 100644
--- a/Sources/TokamakCore/Views/Layout/HStack.swift
+++ b/Sources/TokamakCore/Views/Layout/HStack.swift
@@ -28,7 +28,7 @@ public enum VerticalAlignment: Equatable {
 ///       Text("Hello")
 ///       Text("World")
 ///     }
-public struct HStack<Content>: View where Content: View {
+public struct HStack<Content>: PrimitiveView where Content: View {
   public let alignment: VerticalAlignment
   public let spacing: CGFloat?
   public let content: Content
@@ -42,13 +42,10 @@ public struct HStack<Content>: View where Content: View {
     self.spacing = spacing
     self.content = content()
   }
-
-  public var body: Never {
-    neverBody("HStack")
-  }
 }
 
 extension HStack: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (content as? GroupView)?.children ?? [AnyView(content)]
   }
diff --git a/Sources/TokamakCore/Views/Layout/LazyHGrid.swift b/Sources/TokamakCore/Views/Layout/LazyHGrid.swift
index a19796b6e..eff7f4fe1 100644
--- a/Sources/TokamakCore/Views/Layout/LazyHGrid.swift
+++ b/Sources/TokamakCore/Views/Layout/LazyHGrid.swift
@@ -15,7 +15,7 @@
 //  Created by Carson Katri on 7/13/20.
 //
 
-public struct LazyHGrid<Content>: View where Content: View {
+public struct LazyHGrid<Content>: PrimitiveView where Content: View {
   let rows: [GridItem]
   let alignment: VerticalAlignment
   let spacing: CGFloat
@@ -35,10 +35,6 @@ public struct LazyHGrid<Content>: View where Content: View {
     self.pinnedViews = pinnedViews
     self.content = content()
   }
-
-  public var body: Never {
-    neverBody("LazyVGrid")
-  }
 }
 
 public struct _LazyHGridProxy<Content> where Content: View {
diff --git a/Sources/TokamakCore/Views/Layout/LazyVGrid.swift b/Sources/TokamakCore/Views/Layout/LazyVGrid.swift
index f83581abb..a2f3c937b 100644
--- a/Sources/TokamakCore/Views/Layout/LazyVGrid.swift
+++ b/Sources/TokamakCore/Views/Layout/LazyVGrid.swift
@@ -15,7 +15,7 @@
 //  Created by Carson Katri on 7/13/20.
 //
 
-public struct LazyVGrid<Content>: View where Content: View {
+public struct LazyVGrid<Content>: PrimitiveView where Content: View {
   let columns: [GridItem]
   let alignment: HorizontalAlignment
   let spacing: CGFloat
@@ -35,10 +35,6 @@ public struct LazyVGrid<Content>: View where Content: View {
     self.pinnedViews = pinnedViews
     self.content = content()
   }
-
-  public var body: Never {
-    neverBody("LazyVGrid")
-  }
 }
 
 public struct _LazyVGridProxy<Content> where Content: View {
diff --git a/Sources/TokamakCore/Views/Layout/ScrollView.swift b/Sources/TokamakCore/Views/Layout/ScrollView.swift
index cf14982a4..42d190620 100644
--- a/Sources/TokamakCore/Views/Layout/ScrollView.swift
+++ b/Sources/TokamakCore/Views/Layout/ScrollView.swift
@@ -35,7 +35,7 @@
 ///         Text("\($0)")
 ///       }
 ///     }
-public struct ScrollView<Content>: View where Content: View {
+public struct ScrollView<Content>: PrimitiveView where Content: View {
   public let content: Content
   public let axes: Axis.Set
   public let showsIndicators: Bool
@@ -49,13 +49,10 @@ public struct ScrollView<Content>: View where Content: View {
     self.showsIndicators = showsIndicators
     self.content = content()
   }
-
-  public var body: Never {
-    neverBody("ScrollView")
-  }
 }
 
 extension ScrollView: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (content as? GroupView)?.children ?? [AnyView(content)]
   }
diff --git a/Sources/TokamakCore/Views/Layout/VStack.swift b/Sources/TokamakCore/Views/Layout/VStack.swift
index 8787952ed..f4f921bdc 100644
--- a/Sources/TokamakCore/Views/Layout/VStack.swift
+++ b/Sources/TokamakCore/Views/Layout/VStack.swift
@@ -25,7 +25,7 @@ public enum HorizontalAlignment: Equatable {
 ///       Text("Hello")
 ///       Text("World")
 ///     }
-public struct VStack<Content>: View where Content: View {
+public struct VStack<Content>: PrimitiveView where Content: View {
   public let alignment: HorizontalAlignment
   public let spacing: CGFloat?
   public let content: Content
@@ -39,13 +39,10 @@ public struct VStack<Content>: View where Content: View {
     self.spacing = spacing
     self.content = content()
   }
-
-  public var body: Never {
-    neverBody("VStack")
-  }
 }
 
 extension VStack: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (content as? GroupView)?.children ?? [AnyView(content)]
   }
diff --git a/Sources/TokamakCore/Views/Layout/ZStack.swift b/Sources/TokamakCore/Views/Layout/ZStack.swift
index 75d245b9a..352b7b814 100644
--- a/Sources/TokamakCore/Views/Layout/ZStack.swift
+++ b/Sources/TokamakCore/Views/Layout/ZStack.swift
@@ -43,7 +43,7 @@ public struct Alignment: Equatable {
 ///       Text("Top")
 ///     }
 ///
-public struct ZStack<Content>: View where Content: View {
+public struct ZStack<Content>: PrimitiveView where Content: View {
   public let alignment: Alignment
   public let spacing: CGFloat?
   public let content: Content
@@ -57,13 +57,10 @@ public struct ZStack<Content>: View where Content: View {
     self.spacing = spacing
     self.content = content()
   }
-
-  public var body: Never {
-    neverBody("ZStack")
-  }
 }
 
 extension ZStack: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (content as? GroupView)?.children ?? [AnyView(content)]
   }
diff --git a/Sources/TokamakCore/Views/Navigation/NavigationLink.swift b/Sources/TokamakCore/Views/Navigation/NavigationLink.swift
index 67e9a954b..9071115d0 100644
--- a/Sources/TokamakCore/Views/Navigation/NavigationLink.swift
+++ b/Sources/TokamakCore/Views/Navigation/NavigationLink.swift
@@ -22,7 +22,9 @@ final class NavigationLinkDestination {
   }
 }
 
-public struct NavigationLink<Label, Destination>: View where Label: View, Destination: View {
+public struct NavigationLink<Label, Destination>: PrimitiveView where Label: View,
+  Destination: View
+{
   @State var destination: NavigationLinkDestination
   let label: Label
 
@@ -44,10 +46,6 @@ public struct NavigationLink<Label, Destination>: View where Label: View, Destin
   //    tag: V, selection: Binding<V?>,
   //    @ViewBuilder label: () -> Label
   //   ) where V : Hashable
-
-  public var body: Never {
-    neverBody("NavigationLink")
-  }
 }
 
 public extension NavigationLink where Label == Text {
diff --git a/Sources/TokamakCore/Views/Navigation/NavigationView.swift b/Sources/TokamakCore/Views/Navigation/NavigationView.swift
index 9abce6128..4c7f74667 100644
--- a/Sources/TokamakCore/Views/Navigation/NavigationView.swift
+++ b/Sources/TokamakCore/Views/Navigation/NavigationView.swift
@@ -19,7 +19,7 @@ public final class NavigationContext: ObservableObject {
   @Published var destination = NavigationLinkDestination(EmptyView())
 }
 
-public struct NavigationView<Content>: View where Content: View {
+public struct NavigationView<Content>: PrimitiveView where Content: View {
   let content: Content
 
   @StateObject var context = NavigationContext()
@@ -27,10 +27,6 @@ public struct NavigationView<Content>: View where Content: View {
   public init(@ViewBuilder content: () -> Content) {
     self.content = content()
   }
-
-  public var body: Never {
-    neverBody("NavigationView")
-  }
 }
 
 /// This is a helper type that works around absence of "package private" access control in Swift
diff --git a/Sources/TokamakCore/Views/Selectors/Picker.swift b/Sources/TokamakCore/Views/Selectors/Picker.swift
index 3ce52c50e..3c3bfae2a 100644
--- a/Sources/TokamakCore/Views/Selectors/Picker.swift
+++ b/Sources/TokamakCore/Views/Selectors/Picker.swift
@@ -16,7 +16,7 @@ public protocol _PickerContainerProtocol {
   var elements: [_AnyIDView] { get }
 }
 
-public struct _PickerContainer<Label: View, SelectionValue: Hashable, Content: View>: View,
+public struct _PickerContainer<Label: View, SelectionValue: Hashable, Content: View>: PrimitiveView,
   _PickerContainerProtocol
 {
   @Binding public var selection: SelectionValue
@@ -36,20 +36,12 @@ public struct _PickerContainer<Label: View, SelectionValue: Hashable, Content: V
     self.elements = elements
     self.content = content()
   }
-
-  public var body: Never {
-    neverBody("_PickerLabel")
-  }
 }
 
-public struct _PickerElement: View {
+public struct _PickerElement: PrimitiveView {
   public let valueIndex: Int?
   public let content: AnyView
   @Environment(\.pickerStyle) public var style
-
-  public var body: Never {
-    neverBody("_PickerElement")
-  }
 }
 
 public struct Picker<Label: View, SelectionValue: Hashable, Content: View>: View {
@@ -67,6 +59,7 @@ public struct Picker<Label: View, SelectionValue: Hashable, Content: View>: View
     self.content = content()
   }
 
+  @_spi(TokamakCore)
   public var body: some View {
     let children = self.children
 
@@ -105,12 +98,15 @@ public extension Picker where Label == Text {
 }
 
 extension Picker: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (content as? GroupView)?.children ?? [AnyView(content)]
   }
 }
 
+@_spi(TokamakCore)
 extension Picker: _PickerContainerProtocol {
+  @_spi(TokamakCore)
   public var elements: [_AnyIDView] {
     (content as? ForEachProtocol)?.children
       .compactMap {
diff --git a/Sources/TokamakCore/Views/Selectors/Slider.swift b/Sources/TokamakCore/Views/Selectors/Slider.swift
index 6ffba17ff..09232cbf4 100644
--- a/Sources/TokamakCore/Views/Selectors/Slider.swift
+++ b/Sources/TokamakCore/Views/Selectors/Slider.swift
@@ -28,7 +28,7 @@ private func convert<T: BinaryFloatingPoint>(_ range: ClosedRange<T>) -> ClosedR
 /// A control for selecting a value from a bounded linear range of values.
 ///
 /// Available when `Label` and `ValueLabel` conform to `View`.
-public struct Slider<Label, ValueLabel>: View where Label: View, ValueLabel: View {
+public struct Slider<Label, ValueLabel>: PrimitiveView where Label: View, ValueLabel: View {
   let label: Label
   let minValueLabel: ValueLabel
   let maxValueLabel: ValueLabel
@@ -36,10 +36,6 @@ public struct Slider<Label, ValueLabel>: View where Label: View, ValueLabel: Vie
   let bounds: ClosedRange<Double>
   let step: _SliderStep
   let onEditingChanged: (Bool) -> ()
-
-  public var body: Never {
-    neverBody("Slider")
-  }
 }
 
 public extension Slider where Label == EmptyView, ValueLabel == EmptyView {
@@ -144,6 +140,7 @@ public extension Slider {
 }
 
 extension Slider: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     ((label as? GroupView)?.children ?? [AnyView(label)])
       + ((minValueLabel as? GroupView)?.children ?? [AnyView(minValueLabel)])
diff --git a/Sources/TokamakCore/Views/Selectors/Toggle.swift b/Sources/TokamakCore/Views/Selectors/Toggle.swift
index 058631954..92685cc1e 100644
--- a/Sources/TokamakCore/Views/Selectors/Toggle.swift
+++ b/Sources/TokamakCore/Views/Selectors/Toggle.swift
@@ -25,6 +25,7 @@ public struct Toggle<Label>: View where Label: View {
     self.label = label()
   }
 
+  @_spi(TokamakCore)
   public var body: AnyView {
     toggleStyle.makeBody(
       configuration: ToggleStyleConfiguration(label: AnyView(label), isOn: $isOn)
@@ -48,6 +49,7 @@ public extension Toggle where Label == AnyView {
 }
 
 extension Toggle: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (label as? GroupView)?.children ?? [AnyView(label)]
   }
diff --git a/Sources/TokamakCore/Views/Spacers/Divider.swift b/Sources/TokamakCore/Views/Spacers/Divider.swift
index 33e25a08f..32ab3e382 100644
--- a/Sources/TokamakCore/Views/Spacers/Divider.swift
+++ b/Sources/TokamakCore/Views/Spacers/Divider.swift
@@ -16,10 +16,8 @@
 //
 
 /// A horizontal line for separating content.
-public struct Divider: View {
+public struct Divider: PrimitiveView {
   @Environment(\.self) public var environment
+
   public init() {}
-  public var body: Never {
-    neverBody("Divider")
-  }
 }
diff --git a/Sources/TokamakCore/Views/Spacers/Spacer.swift b/Sources/TokamakCore/Views/Spacers/Spacer.swift
index 21cb60dca..0d316e870 100644
--- a/Sources/TokamakCore/Views/Spacers/Spacer.swift
+++ b/Sources/TokamakCore/Views/Spacers/Spacer.swift
@@ -22,14 +22,10 @@
 ///       Spacer()
 ///       Text("World")
 ///     }
-public struct Spacer: View {
+public struct Spacer: PrimitiveView {
   public var minLength: CGFloat?
 
   public init(minLength: CGFloat? = nil) {
     self.minLength = minLength
   }
-
-  public var body: Never {
-    neverBody("Spacer")
-  }
 }
diff --git a/Sources/TokamakCore/Views/Text/SecureField.swift b/Sources/TokamakCore/Views/Text/SecureField.swift
index 638495674..72a2c7554 100644
--- a/Sources/TokamakCore/Views/Text/SecureField.swift
+++ b/Sources/TokamakCore/Views/Text/SecureField.swift
@@ -35,14 +35,10 @@
 ///         print("Set password")
 ///       })
 ///     }
-public struct SecureField<Label>: View where Label: View {
+public struct SecureField<Label>: PrimitiveView where Label: View {
   let label: Label
   let textBinding: Binding<String>
   let onCommit: () -> ()
-
-  public var body: Never {
-    neverBody("SecureField")
-  }
 }
 
 public extension SecureField where Label == Text {
@@ -57,6 +53,7 @@ public extension SecureField where Label == Text {
 }
 
 extension SecureField: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (label as? GroupView)?.children ?? [AnyView(label)]
   }
diff --git a/Sources/TokamakCore/Views/Text/Text.swift b/Sources/TokamakCore/Views/Text/Text.swift
index 84b4801f0..a4fa79ceb 100644
--- a/Sources/TokamakCore/Views/Text/Text.swift
+++ b/Sources/TokamakCore/Views/Text/Text.swift
@@ -29,7 +29,7 @@
 ///       .bold()
 ///       .italic()
 ///       .underline(true, color: .red)
-public struct Text: View {
+public struct Text: PrimitiveView {
   let storage: _Storage
   let modifiers: [_Modifier]
 
@@ -71,10 +71,6 @@ public struct Text: View {
   public init<S>(_ content: S) where S: StringProtocol {
     self.init(storage: .verbatim(String(content)))
   }
-
-  public var body: Never {
-    neverBody("Text")
-  }
 }
 
 public extension Text._Storage {
diff --git a/Sources/TokamakCore/Views/Text/TextEditor.swift b/Sources/TokamakCore/Views/Text/TextEditor.swift
index 41ed14819..a3b0a68a8 100644
--- a/Sources/TokamakCore/Views/Text/TextEditor.swift
+++ b/Sources/TokamakCore/Views/Text/TextEditor.swift
@@ -12,16 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-public struct TextEditor: View {
+public struct TextEditor: PrimitiveView {
   let textBinding: Binding<String>
 
   public init(text: Binding<String>) {
     textBinding = text
   }
-
-  public var body: Never {
-    neverBody("TextEditor")
-  }
 }
 
 public struct _TextEditorProxy {
diff --git a/Sources/TokamakCore/Views/Text/TextField.swift b/Sources/TokamakCore/Views/Text/TextField.swift
index 328d2caf6..fdd060fef 100644
--- a/Sources/TokamakCore/Views/Text/TextField.swift
+++ b/Sources/TokamakCore/Views/Text/TextField.swift
@@ -34,16 +34,12 @@
 ///         print("Set username")
 ///       })
 ///     }
-public struct TextField<Label>: View where Label: View {
+public struct TextField<Label>: PrimitiveView where Label: View {
   let label: Label
   let textBinding: Binding<String>
   let onEditingChanged: (Bool) -> ()
   let onCommit: () -> ()
   @Environment(\.textFieldStyle) var style
-
-  public var body: Never {
-    neverBody("TextField")
-  }
 }
 
 public extension TextField where Label == Text {
@@ -68,6 +64,7 @@ public extension TextField where Label == Text {
 }
 
 extension TextField: ParentView {
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     (label as? GroupView)?.children ?? [AnyView(label)]
   }
diff --git a/Sources/TokamakCore/Views/View.swift b/Sources/TokamakCore/Views/View.swift
index b3e598caa..32b144b18 100644
--- a/Sources/TokamakCore/Views/View.swift
+++ b/Sources/TokamakCore/Views/View.swift
@@ -22,12 +22,23 @@ public protocol View {
 }
 
 public extension Never {
+  @_spi(TokamakCore)
   var body: Never {
-    neverBody("Never")
+    fatalError()
   }
 }
 
-extension Never: View {}
+extension Never: PrimitiveView {}
+
+/// A `View` that offers primitive functionality, which renders its `body` inaccessible.
+public protocol PrimitiveView: View where Body == Never {}
+
+public extension PrimitiveView {
+  @_spi(TokamakCore)
+  var body: Never {
+    neverBody(String(describing: Self.self))
+  }
+}
 
 /// A `View` type that renders with subviews, usually specified in the `Content` type argument
 public protocol ParentView {
diff --git a/Sources/TokamakCore/Views/ViewBuilder.swift b/Sources/TokamakCore/Views/ViewBuilder.swift
index 3560dd29a..16943c071 100644
--- a/Sources/TokamakCore/Views/ViewBuilder.swift
+++ b/Sources/TokamakCore/Views/ViewBuilder.swift
@@ -16,17 +16,13 @@
 //
 
 /// A `View` with no effect on rendering.
-public struct EmptyView: View {
+public struct EmptyView: PrimitiveView {
   @inlinable
   public init() {}
-
-  public var body: Never {
-    neverBody("EmptyView")
-  }
 }
 
 // swiftlint:disable:next type_name
-public struct _ConditionalContent<TrueContent, FalseContent>: View
+public struct _ConditionalContent<TrueContent, FalseContent>: PrimitiveView
   where TrueContent: View, FalseContent: View
 {
   enum Storage {
@@ -35,10 +31,6 @@ public struct _ConditionalContent<TrueContent, FalseContent>: View
   }
 
   let storage: Storage
-
-  public var body: Never {
-    neverBody("_ConditionContent")
-  }
 }
 
 extension _ConditionalContent: GroupView {
diff --git a/Sources/TokamakDOM/DOMRef.swift b/Sources/TokamakDOM/DOMRef.swift
index c592916df..21b71c821 100644
--- a/Sources/TokamakDOM/DOMRef.swift
+++ b/Sources/TokamakDOM/DOMRef.swift
@@ -13,7 +13,7 @@
 // limitations under the License.
 
 import JavaScriptKit
-import TokamakCore
+@_spi(TokamakCore) import TokamakCore
 
 public extension View {
   /** Allows capturing DOM references of host views. The resulting reference is written
diff --git a/Sources/TokamakDOM/DOMRenderer.swift b/Sources/TokamakDOM/DOMRenderer.swift
index 3747868db..d9f430bea 100644
--- a/Sources/TokamakDOM/DOMRenderer.swift
+++ b/Sources/TokamakDOM/DOMRenderer.swift
@@ -17,7 +17,7 @@
 
 import JavaScriptKit
 import OpenCombineJS
-import TokamakCore
+@_spi(TokamakCore) import TokamakCore
 import TokamakStaticHTML
 
 extension EnvironmentValues {
diff --git a/Sources/TokamakDOM/Styles/ButtonStyle.swift b/Sources/TokamakDOM/Styles/ButtonStyle.swift
index c64ca0a31..08fd49800 100644
--- a/Sources/TokamakDOM/Styles/ButtonStyle.swift
+++ b/Sources/TokamakDOM/Styles/ButtonStyle.swift
@@ -18,6 +18,7 @@
 import TokamakCore
 
 extension ButtonStyleConfiguration.Label: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     _ButtonStyleConfigurationProxy.Label(self).content
   }
diff --git a/Sources/TokamakDOM/Views/Buttons/Button.swift b/Sources/TokamakDOM/Views/Buttons/Button.swift
index 3f18024b3..1ca88f3d8 100644
--- a/Sources/TokamakDOM/Views/Buttons/Button.swift
+++ b/Sources/TokamakDOM/Views/Buttons/Button.swift
@@ -19,6 +19,7 @@ import TokamakCore
 import TokamakStaticHTML
 
 extension _Button: ViewDeferredToRenderer where Label == Text {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let listeners: [String: Listener] = [
       "pointerdown": { _ in isPressed = true },
diff --git a/Sources/TokamakDOM/Views/Containers/DisclosureGroup.swift b/Sources/TokamakDOM/Views/Containers/DisclosureGroup.swift
index 88b2129cf..3b3b17879 100644
--- a/Sources/TokamakDOM/Views/Containers/DisclosureGroup.swift
+++ b/Sources/TokamakDOM/Views/Containers/DisclosureGroup.swift
@@ -70,6 +70,7 @@ extension DisclosureGroup: ViewDeferredToRenderer {
     }
   }
 
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(HTML("div", [
       "class": "_tokamak-disclosuregroup",
diff --git a/Sources/TokamakDOM/Views/DynamicHTML.swift b/Sources/TokamakDOM/Views/DynamicHTML.swift
index 0922504fc..121845db5 100644
--- a/Sources/TokamakDOM/Views/DynamicHTML.swift
+++ b/Sources/TokamakDOM/Views/DynamicHTML.swift
@@ -35,6 +35,7 @@ public struct DynamicHTML<Content>: View, AnyDynamicHTML {
 
   public var innerHTML: String?
 
+  @_spi(TokamakCore)
   public var body: Never {
     neverBody("HTML")
   }
@@ -69,6 +70,7 @@ extension DynamicHTML: ParentView where Content: View {
     innerHTML = nil
   }
 
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     [AnyView(content)]
   }
diff --git a/Sources/TokamakDOM/Views/Layout/GeometryReader.swift b/Sources/TokamakDOM/Views/Layout/GeometryReader.swift
index bd830bfe1..082e32b17 100644
--- a/Sources/TokamakDOM/Views/Layout/GeometryReader.swift
+++ b/Sources/TokamakDOM/Views/Layout/GeometryReader.swift
@@ -13,12 +13,13 @@
 // limitations under the License.
 
 import JavaScriptKit
-import TokamakCore
+@_spi(TokamakCore) import TokamakCore
 import TokamakStaticHTML
 
 private let ResizeObserver = JSObject.global.ResizeObserver.function!
 
 extension GeometryReader: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(_GeometryReader(content: content))
   }
diff --git a/Sources/TokamakDOM/Views/Navigation/NavigationLink.swift b/Sources/TokamakDOM/Views/Navigation/NavigationLink.swift
index 6089a946c..873e2b708 100644
--- a/Sources/TokamakDOM/Views/Navigation/NavigationLink.swift
+++ b/Sources/TokamakDOM/Views/Navigation/NavigationLink.swift
@@ -16,6 +16,7 @@ import TokamakCore
 import TokamakStaticHTML
 
 extension NavigationLink: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _NavigationLinkProxy(self)
     return AnyView(
diff --git a/Sources/TokamakDOM/Views/Selectors/Picker.swift b/Sources/TokamakDOM/Views/Selectors/Picker.swift
index 4c93ab164..cfce0f270 100644
--- a/Sources/TokamakDOM/Views/Selectors/Picker.swift
+++ b/Sources/TokamakDOM/Views/Selectors/Picker.swift
@@ -17,6 +17,7 @@ import TokamakCore
 import TokamakStaticHTML
 
 extension _PickerContainer: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(HTML("label") {
       label
@@ -35,6 +36,7 @@ extension _PickerContainer: ViewDeferredToRenderer {
 }
 
 extension _PickerElement: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let attributes: [HTMLAttribute: String]
     if let value = valueIndex {
diff --git a/Sources/TokamakDOM/Views/Selectors/Slider.swift b/Sources/TokamakDOM/Views/Selectors/Slider.swift
index 3378dfd9b..862afbbdd 100644
--- a/Sources/TokamakDOM/Views/Selectors/Slider.swift
+++ b/Sources/TokamakDOM/Views/Selectors/Slider.swift
@@ -17,6 +17,7 @@ import TokamakCore
 import TokamakStaticHTML
 
 extension Slider: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _SliderProxy(self)
     let step: String
diff --git a/Sources/TokamakDOM/Views/Text/SecureField.swift b/Sources/TokamakDOM/Views/Text/SecureField.swift
index 054839e4d..ad95a0cf6 100644
--- a/Sources/TokamakDOM/Views/Text/SecureField.swift
+++ b/Sources/TokamakDOM/Views/Text/SecureField.swift
@@ -18,6 +18,7 @@
 import TokamakCore
 
 extension SecureField: ViewDeferredToRenderer where Label == Text {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _SecureFieldProxy(self)
     return AnyView(DynamicHTML("input", [
diff --git a/Sources/TokamakDOM/Views/Text/TextEditor.swift b/Sources/TokamakDOM/Views/Text/TextEditor.swift
index 0266ef3a4..5eeaff3f1 100644
--- a/Sources/TokamakDOM/Views/Text/TextEditor.swift
+++ b/Sources/TokamakDOM/Views/Text/TextEditor.swift
@@ -15,6 +15,7 @@
 import TokamakCore
 
 extension TextEditor: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _TextEditorProxy(self)
 
diff --git a/Sources/TokamakDOM/Views/Text/TextField.swift b/Sources/TokamakDOM/Views/Text/TextField.swift
index 020ee2784..f770e6362 100644
--- a/Sources/TokamakDOM/Views/Text/TextField.swift
+++ b/Sources/TokamakDOM/Views/Text/TextField.swift
@@ -39,6 +39,7 @@ extension TextField: ViewDeferredToRenderer where Label == Text {
     }
   }
 
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _TextFieldProxy(self)
 
diff --git a/Sources/TokamakGTK/Modifiers/WidgetModifier.swift b/Sources/TokamakGTK/Modifiers/WidgetModifier.swift
index fbd51f1cb..e990d0894 100644
--- a/Sources/TokamakGTK/Modifiers/WidgetModifier.swift
+++ b/Sources/TokamakGTK/Modifiers/WidgetModifier.swift
@@ -51,6 +51,7 @@ extension WidgetAttributeModifier {
 }
 
 extension ModifiedContent: ViewDeferredToRenderer where Content: View {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     guard let widgetModifier = modifier as? WidgetModifier else {
       return AnyView(content)
diff --git a/Sources/TokamakGTK/Shapes/Shape.swift b/Sources/TokamakGTK/Shapes/Shape.swift
index 42b8cf582..36e9078a9 100644
--- a/Sources/TokamakGTK/Shapes/Shape.swift
+++ b/Sources/TokamakGTK/Shapes/Shape.swift
@@ -51,6 +51,7 @@ func createPath(from elements: [Path.Element], in cr: OpaquePointer) {
 }
 
 extension _ShapeView: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(WidgetView(build: { _ in
       let w = gtk_drawing_area_new()
diff --git a/Sources/TokamakGTK/Tokens/BuiltinColors.swift b/Sources/TokamakGTK/Tokens/BuiltinColors.swift
index 1fee3e957..291616fa1 100644
--- a/Sources/TokamakGTK/Tokens/BuiltinColors.swift
+++ b/Sources/TokamakGTK/Tokens/BuiltinColors.swift
@@ -15,7 +15,7 @@
 //  Created by Carson Katri on 8/4/20.
 //
 
-import TokamakCore
+@_spi(TokamakCore) import TokamakCore
 
 // MARK: List Colors
 
diff --git a/Sources/TokamakGTK/Views/List.swift b/Sources/TokamakGTK/Views/List.swift
index 58d944af1..4d5e68e30 100644
--- a/Sources/TokamakGTK/Views/List.swift
+++ b/Sources/TokamakGTK/Views/List.swift
@@ -31,6 +31,7 @@ extension List: ViewDeferredToRenderer {
     }
   }
 
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _ListProxy(self)
     return AnyView(ScrollView {
diff --git a/Sources/TokamakGTK/Views/NavigationView.swift b/Sources/TokamakGTK/Views/NavigationView.swift
index ae4f16326..005ac8b23 100644
--- a/Sources/TokamakGTK/Views/NavigationView.swift
+++ b/Sources/TokamakGTK/Views/NavigationView.swift
@@ -59,6 +59,7 @@ protocol GtkStackProtocol {}
 // }
 
 extension NavigationView: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _NavigationViewProxy(self)
     return AnyView(HStack {
@@ -70,6 +71,7 @@ extension NavigationView: ViewDeferredToRenderer {
 }
 
 extension NavigationLink: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _NavigationLinkProxy(self)
     return AnyView(Button(action: { proxy.activate() }) {
diff --git a/Sources/TokamakGTK/Views/ScrollView.swift b/Sources/TokamakGTK/Views/ScrollView.swift
index 71ef78d97..e991a8d33 100644
--- a/Sources/TokamakGTK/Views/ScrollView.swift
+++ b/Sources/TokamakGTK/Views/ScrollView.swift
@@ -19,6 +19,7 @@ import CGTK
 import TokamakCore
 
 extension ScrollView: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(WidgetView(build: { _ in
       gtk_scrolled_window_new(nil, nil)
diff --git a/Sources/TokamakGTK/Views/Stack.swift b/Sources/TokamakGTK/Views/Stack.swift
index 034655856..a18f65bce 100644
--- a/Sources/TokamakGTK/Views/Stack.swift
+++ b/Sources/TokamakGTK/Views/Stack.swift
@@ -53,6 +53,7 @@ struct Box<Content: View>: View, ParentView, AnyWidget, StackProtocol {
 }
 
 extension VStack: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(
       Box(
@@ -66,6 +67,7 @@ extension VStack: ViewDeferredToRenderer {
 }
 
 extension HStack: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(
       Box(
diff --git a/Sources/TokamakGTK/Views/TextField.swift b/Sources/TokamakGTK/Views/TextField.swift
index 1638f3d27..9c273b7c6 100644
--- a/Sources/TokamakGTK/Views/TextField.swift
+++ b/Sources/TokamakGTK/Views/TextField.swift
@@ -57,6 +57,7 @@ private func bindAction(to entry: UnsafeMutablePointer<GtkWidget>, textBinding:
 }
 
 extension SecureField: ViewDeferredToRenderer where Label == Text {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _SecureFieldProxy(self)
     return AnyView(WidgetView(
@@ -72,6 +73,7 @@ extension SecureField: ViewDeferredToRenderer where Label == Text {
 }
 
 extension TextField: ViewDeferredToRenderer where Label == Text {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _TextFieldProxy(self)
     return AnyView(WidgetView(
diff --git a/Sources/TokamakStaticHTML/Modifiers/ModifiedContent.swift b/Sources/TokamakStaticHTML/Modifiers/ModifiedContent.swift
index 2bb65b5ba..a652277f6 100644
--- a/Sources/TokamakStaticHTML/Modifiers/ModifiedContent.swift
+++ b/Sources/TokamakStaticHTML/Modifiers/ModifiedContent.swift
@@ -30,6 +30,7 @@ extension ModifiedContent: AnyModifiedContent where Modifier: DOMViewModifier, C
 }
 
 extension ModifiedContent: ViewDeferredToRenderer where Content: View, Modifier: ViewModifier {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     if let domModifier = modifier as? DOMViewModifier {
       if let adjacentModifier = content as? AnyModifiedContent,
diff --git a/Sources/TokamakStaticHTML/Shapes/Path.swift b/Sources/TokamakStaticHTML/Shapes/Path.swift
index de4a635f5..4270f1b76 100644
--- a/Sources/TokamakStaticHTML/Shapes/Path.swift
+++ b/Sources/TokamakStaticHTML/Shapes/Path.swift
@@ -128,6 +128,7 @@ extension Path: ViewDeferredToRenderer {
     svgFrom(storage: storage, strokeStyle: strokeStyle)
   }
 
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let sizeStyle = sizing == .flexible ?
       """
diff --git a/Sources/TokamakStaticHTML/Shapes/_ShapeView.swift b/Sources/TokamakStaticHTML/Shapes/_ShapeView.swift
index 46abba0cc..696e84ec9 100644
--- a/Sources/TokamakStaticHTML/Shapes/_ShapeView.swift
+++ b/Sources/TokamakStaticHTML/Shapes/_ShapeView.swift
@@ -32,6 +32,7 @@ extension _StrokedShape: ShapeAttributes {
 }
 
 extension _ShapeView: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let path = shape.path(in: .zero).deferredBody
     if let shapeAttributes = shape as? ShapeAttributes {
diff --git a/Sources/TokamakStaticHTML/Tokens/BuiltinColors.swift b/Sources/TokamakStaticHTML/Tokens/BuiltinColors.swift
index 1fee3e957..291616fa1 100644
--- a/Sources/TokamakStaticHTML/Tokens/BuiltinColors.swift
+++ b/Sources/TokamakStaticHTML/Tokens/BuiltinColors.swift
@@ -15,7 +15,7 @@
 //  Created by Carson Katri on 8/4/20.
 //
 
-import TokamakCore
+@_spi(TokamakCore) import TokamakCore
 
 // MARK: List Colors
 
diff --git a/Sources/TokamakStaticHTML/Views/Buttons/Link.swift b/Sources/TokamakStaticHTML/Views/Buttons/Link.swift
index 38e67405e..5d5ef7f45 100644
--- a/Sources/TokamakStaticHTML/Views/Buttons/Link.swift
+++ b/Sources/TokamakStaticHTML/Views/Buttons/Link.swift
@@ -18,6 +18,7 @@
 import TokamakCore
 
 extension Link: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _LinkProxy(self)
     return AnyView(HTML("a", ["href": proxy.destination.absoluteString, "class": "_tokamak-link"]) {
diff --git a/Sources/TokamakStaticHTML/Views/Containers/List.swift b/Sources/TokamakStaticHTML/Views/Containers/List.swift
index d4be21259..4b49f507b 100644
--- a/Sources/TokamakStaticHTML/Views/Containers/List.swift
+++ b/Sources/TokamakStaticHTML/Views/Containers/List.swift
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import TokamakCore
+@_spi(TokamakCore) import TokamakCore
 
 extension PlainListStyle: ListStyleDeferredToRenderer {
   public func sectionHeader<Header>(_ header: Header) -> AnyView where Header: View {
diff --git a/Sources/TokamakStaticHTML/Views/HTML.swift b/Sources/TokamakStaticHTML/Views/HTML.swift
index b608006cf..c4343ab27 100644
--- a/Sources/TokamakStaticHTML/Views/HTML.swift
+++ b/Sources/TokamakStaticHTML/Views/HTML.swift
@@ -70,6 +70,7 @@ public struct HTML<Content>: View, AnyHTML {
 
   public let innerHTML: String?
 
+  @_spi(TokamakCore)
   public var body: Never {
     neverBody("HTML")
   }
@@ -100,6 +101,7 @@ extension HTML: ParentView where Content: View {
     innerHTML = nil
   }
 
+  @_spi(TokamakCore)
   public var children: [AnyView] {
     [AnyView(content)]
   }
diff --git a/Sources/TokamakStaticHTML/Views/Images/Image.swift b/Sources/TokamakStaticHTML/Views/Images/Image.swift
index b55e8e7e0..e77b1066f 100644
--- a/Sources/TokamakStaticHTML/Views/Images/Image.swift
+++ b/Sources/TokamakStaticHTML/Views/Images/Image.swift
@@ -20,6 +20,7 @@ import TokamakCore
 public typealias Image = TokamakCore.Image
 
 extension Image: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(_HTMLImage(proxy: _ImageProxy(self)))
   }
diff --git a/Sources/TokamakStaticHTML/Views/Layout/HStack.swift b/Sources/TokamakStaticHTML/Views/Layout/HStack.swift
index b302b68e9..90a3a8214 100644
--- a/Sources/TokamakStaticHTML/Views/Layout/HStack.swift
+++ b/Sources/TokamakStaticHTML/Views/Layout/HStack.swift
@@ -30,6 +30,7 @@ extension VerticalAlignment {
 extension HStack: ViewDeferredToRenderer, SpacerContainer {
   public var axis: SpacerContainerAxis { .horizontal }
 
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(HTML("div", [
       "style": """
diff --git a/Sources/TokamakStaticHTML/Views/Layout/LazyHGrid.swift b/Sources/TokamakStaticHTML/Views/Layout/LazyHGrid.swift
index c9548a44b..20d30a045 100644
--- a/Sources/TokamakStaticHTML/Views/Layout/LazyHGrid.swift
+++ b/Sources/TokamakStaticHTML/Views/Layout/LazyHGrid.swift
@@ -36,6 +36,7 @@ extension LazyHGrid: ViewDeferredToRenderer {
     _LazyHGridProxy(self).rows.last
   }
 
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     var styles = """
     display: grid;
diff --git a/Sources/TokamakStaticHTML/Views/Layout/LazyVGrid.swift b/Sources/TokamakStaticHTML/Views/Layout/LazyVGrid.swift
index f9e94e342..40b5a17a2 100644
--- a/Sources/TokamakStaticHTML/Views/Layout/LazyVGrid.swift
+++ b/Sources/TokamakStaticHTML/Views/Layout/LazyVGrid.swift
@@ -36,6 +36,7 @@ extension LazyVGrid: ViewDeferredToRenderer {
     _LazyVGridProxy(self).columns.last
   }
 
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     var styles = """
     display: grid;
diff --git a/Sources/TokamakStaticHTML/Views/Layout/ScrollView.swift b/Sources/TokamakStaticHTML/Views/Layout/ScrollView.swift
index 3b9368887..a9e40a771 100644
--- a/Sources/TokamakStaticHTML/Views/Layout/ScrollView.swift
+++ b/Sources/TokamakStaticHTML/Views/Layout/ScrollView.swift
@@ -26,6 +26,7 @@ extension ScrollView: ViewDeferredToRenderer, SpacerContainer {
     }
   }
 
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let scrollX = axes.contains(.horizontal)
     let scrollY = axes.contains(.vertical)
diff --git a/Sources/TokamakStaticHTML/Views/Layout/VStack.swift b/Sources/TokamakStaticHTML/Views/Layout/VStack.swift
index 0483f6ff8..75af304bb 100644
--- a/Sources/TokamakStaticHTML/Views/Layout/VStack.swift
+++ b/Sources/TokamakStaticHTML/Views/Layout/VStack.swift
@@ -30,6 +30,7 @@ extension HorizontalAlignment {
 extension VStack: ViewDeferredToRenderer, SpacerContainer {
   public var axis: SpacerContainerAxis { .vertical }
 
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(HTML("div", [
       "style": """
diff --git a/Sources/TokamakStaticHTML/Views/Layout/ZStack.swift b/Sources/TokamakStaticHTML/Views/Layout/ZStack.swift
index b60f51294..003881669 100644
--- a/Sources/TokamakStaticHTML/Views/Layout/ZStack.swift
+++ b/Sources/TokamakStaticHTML/Views/Layout/ZStack.swift
@@ -23,6 +23,7 @@ struct _ZStack_ContentGridItem: ViewModifier, DOMViewModifier {
 }
 
 extension ZStack: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(HTML("div", [
       "style": """
diff --git a/Sources/TokamakStaticHTML/Views/Navigation/NavigationView.swift b/Sources/TokamakStaticHTML/Views/Navigation/NavigationView.swift
index afc329434..5c9145eab 100644
--- a/Sources/TokamakStaticHTML/Views/Navigation/NavigationView.swift
+++ b/Sources/TokamakStaticHTML/Views/Navigation/NavigationView.swift
@@ -15,6 +15,7 @@
 import TokamakCore
 
 extension NavigationView: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     let proxy = _NavigationViewProxy(self)
     return AnyView(HTML("div", [
diff --git a/Sources/TokamakStaticHTML/Views/Spacers/Divider.swift b/Sources/TokamakStaticHTML/Views/Spacers/Divider.swift
index 47c2f8869..7e9a8d9b1 100644
--- a/Sources/TokamakStaticHTML/Views/Spacers/Divider.swift
+++ b/Sources/TokamakStaticHTML/Views/Spacers/Divider.swift
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import TokamakCore
+@_spi(TokamakCore) import TokamakCore
 
 extension Divider: AnyHTML {
   public var innerHTML: String? { nil }
diff --git a/Sources/TokamakStaticHTML/Views/Spacers/Spacer.swift b/Sources/TokamakStaticHTML/Views/Spacers/Spacer.swift
index 1be491fd2..eedc24d12 100644
--- a/Sources/TokamakStaticHTML/Views/Spacers/Spacer.swift
+++ b/Sources/TokamakStaticHTML/Views/Spacers/Spacer.swift
@@ -56,6 +56,7 @@ public extension SpacerContainer where Self: ParentView {
 }
 
 extension Spacer: ViewDeferredToRenderer {
+  @_spi(TokamakCore)
   public var deferredBody: AnyView {
     AnyView(HTML("div", [
       "style": "flex-grow: 1; \(minLength != nil ? "min-width: \(minLength!)" : "")",
diff --git a/Tests/TokamakTests/ReconcilerTests.swift b/Tests/TokamakTests/ReconcilerTests.swift
index cc9e66a78..d45160fc7 100644
--- a/Tests/TokamakTests/ReconcilerTests.swift
+++ b/Tests/TokamakTests/ReconcilerTests.swift
@@ -15,7 +15,7 @@
 //  Created by Max Desiatov on 07/12/2018.
 //
 
-import TokamakTestRenderer
+@_spi(TokamakCore) import TokamakTestRenderer
 import XCTest
 
 @testable import TokamakCore