diff --git a/Package.swift b/Package.swift
index 6bf2bd76..610dd78f 100644
--- a/Package.swift
+++ b/Package.swift
@@ -17,13 +17,21 @@ func envEnable(_ key: String, default defaultValue: Bool = false) -> Bool {
     }
 }
 
-let isXcodeEnv = Context.environment["__CFBundleIdentifier"] == "com.apple.dt.Xcode"
-let development = envEnable("OPENSWIFTUI_DEVELOPMENT", default: false)
-
-// Xcode use clang as linker which supports "-iframework" while SwiftPM use swiftc as linker which supports "-Fsystem"
-let systemFrameworkSearchFlag = isXcodeEnv ? "-iframework" : "-Fsystem"
+var sharedSwiftSettings: [SwiftSetting] = [
+    .enableUpcomingFeature("BareSlashRegexLiterals"),
+    .enableUpcomingFeature("InternalImportsByDefault"),
+    .define("OPENSWIFTUI_SUPPRESS_DEPRECATED_WARNINGS"),
+    .swiftLanguageMode(.v5),
+]
 
 let releaseVersion = Context.environment["OPENSWIFTUI_TARGET_RELEASE"].flatMap { Int($0) } ?? 2024
+sharedSwiftSettings.append(.define("OPENSWIFTUI_RELEASE_\(releaseVersion)"))
+if releaseVersion >= 2021 {
+    for year in 2021 ... releaseVersion {
+        sharedSwiftSettings.append(.define("OPENSWIFTUI_SUPPORT_\(year)_API"))
+    }
+}
+
 let platforms: [SupportedPlatform] = switch releaseVersion {
 case 2024: // iOS 18.0
     [
@@ -53,18 +61,15 @@ default:
     ]
 }
 
-var sharedSwiftSettings: [SwiftSetting] = [
-    .enableUpcomingFeature("BareSlashRegexLiterals"),
-    .enableUpcomingFeature("InternalImportsByDefault"),
-    .define("OPENSWIFTUI_SUPPRESS_DEPRECATED_WARNINGS"),
-    .define("OPENSWIFTUI_RELEASE_\(releaseVersion)"),
-    .swiftLanguageMode(.v5),
-]
+let isXcodeEnv = Context.environment["__CFBundleIdentifier"] == "com.apple.dt.Xcode"
 
-if releaseVersion >= 2021 {
-    for year in 2021 ... releaseVersion {
-        sharedSwiftSettings.append(.define("OPENSWIFTUI_SUPPORT_\(year)_API"))
-    }
+// Xcode use clang as linker which supports "-iframework" while SwiftPM use swiftc as linker which supports "-Fsystem"
+let systemFrameworkSearchFlag = isXcodeEnv ? "-iframework" : "-Fsystem"
+
+let development = envEnable("OPENSWIFTUI_DEVELOPMENT")
+
+if development {
+    sharedSwiftSettings.append(.define("OPENSWIFTUI_DEVELOPMENT"))
 }
 
 let warningsAsErrorsCondition = envEnable("OPENSWIFTUI_WERROR", default: isXcodeEnv && development)
diff --git a/Sources/OpenSwiftUI/Accessibility/Modifier/internal/AccessibilityConfigurationModifier.swift b/Sources/OpenSwiftUI/Accessibility/Modifier/internal/AccessibilityConfigurationModifier.swift
index d6971dec..e1c7c145 100644
--- a/Sources/OpenSwiftUI/Accessibility/Modifier/internal/AccessibilityConfigurationModifier.swift
+++ b/Sources/OpenSwiftUI/Accessibility/Modifier/internal/AccessibilityConfigurationModifier.swift
@@ -15,5 +15,5 @@ protocol AccessibilityConfigurationModifier {
 }
 
 extension AccessibilityConfigurationModifier where Configuration == Never {
-    var configuration: Configuration { fatalError() }
+    var configuration: Configuration { preconditionFailure("") }
 }
diff --git a/Sources/OpenSwiftUI/App/FinishLaunchTestAction.swift b/Sources/OpenSwiftUI/App/FinishLaunchTestAction.swift
index 2219a6a6..92477b9a 100644
--- a/Sources/OpenSwiftUI/App/FinishLaunchTestAction.swift
+++ b/Sources/OpenSwiftUI/App/FinishLaunchTestAction.swift
@@ -17,7 +17,7 @@ struct FinishLaunchTestAction {
         #if os(iOS)
         UIApplication.shared.finishedTest(UIApplication.shared._launchTestName())
         #else
-        fatalError("Unimplemented for other platform")
+        preconditionFailure("Unimplemented for other platform")
         #endif
     }
 }
diff --git a/Sources/OpenSwiftUI/App/LegacyApp.swift b/Sources/OpenSwiftUI/App/LegacyApp.swift
index 03b9a7a5..677fe3e3 100644
--- a/Sources/OpenSwiftUI/App/LegacyApp.swift
+++ b/Sources/OpenSwiftUI/App/LegacyApp.swift
@@ -19,7 +19,7 @@ extension __App {
         var rootView: V
         
         init() {
-            fatalError("Not a standalone App.")
+            preconditionFailure("Not a standalone App.")
         }
         
         init(rootView: V) {
diff --git a/Sources/OpenSwiftUI/App/OpenSwiftUIApplication.swift b/Sources/OpenSwiftUI/App/OpenSwiftUIApplication.swift
index 611bf46b..ee16e1f4 100644
--- a/Sources/OpenSwiftUI/App/OpenSwiftUIApplication.swift
+++ b/Sources/OpenSwiftUI/App/OpenSwiftUIApplication.swift
@@ -25,7 +25,7 @@ private final class OpenSwiftUIApplication: NSApplication {
     }
     
     required init?(coder: NSCoder) {
-        fatalError("init(coder:) has not been implemented")
+        preconditionFailure("init(coder:) has not been implemented")
     }
 }
 #else
diff --git a/Sources/OpenSwiftUI/Core/Modifier/SceneModifier/TODO/_SceneModifier.swift b/Sources/OpenSwiftUI/Core/Modifier/SceneModifier/TODO/_SceneModifier.swift
index cb99b349..a0e37d23 100644
--- a/Sources/OpenSwiftUI/Core/Modifier/SceneModifier/TODO/_SceneModifier.swift
+++ b/Sources/OpenSwiftUI/Core/Modifier/SceneModifier/TODO/_SceneModifier.swift
@@ -22,6 +22,6 @@ extension _SceneModifier {
 extension _SceneModifier where Body == Never {
     @inline(__always)
     public func body(content _: SceneContent) -> Body {
-        fatalError("body() should not be called on \(Self.self)")
+        preconditionFailure("body() should not be called on \(Self.self)")
     }
 }
diff --git a/Sources/OpenSwiftUI/Core/Render/DisplayLink.swift b/Sources/OpenSwiftUI/Core/Render/DisplayLink.swift
index 93728210..1ab812c7 100644
--- a/Sources/OpenSwiftUI/Core/Render/DisplayLink.swift
+++ b/Sources/OpenSwiftUI/Core/Render/DisplayLink.swift
@@ -28,11 +28,11 @@ final class DisplayLink: NSObject {
     
     #if os(iOS)
     init(host: AnyUIHostingView, window: UIWindow) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     #elseif os(macOS)
     init(host: AnyUIHostingView, window: NSWindow) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     #endif
     
diff --git a/Sources/OpenSwiftUI/EventHandling/Focus/FocusStoreLocation.swift b/Sources/OpenSwiftUI/EventHandling/Focus/FocusStoreLocation.swift
index 4a0463b5..458bb7dc 100644
--- a/Sources/OpenSwiftUI/EventHandling/Focus/FocusStoreLocation.swift
+++ b/Sources/OpenSwiftUI/EventHandling/Focus/FocusStoreLocation.swift
@@ -11,16 +11,16 @@ class FocusStoreLocation<A: Hashable>: AnyLocation<A>, @unchecked Sendable {
     }
     
     override func get() -> A {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     override func set(_ value: A, transaction: Transaction) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     typealias Value = A
     
-    override init() { fatalError() }
+    override init() { preconditionFailure("") }
     
     var store: FocusStore
     weak var host: GraphHost?
diff --git a/Sources/OpenSwiftUI/Integration/Representable/UIKit/UIViewRepresentable.swift b/Sources/OpenSwiftUI/Integration/Representable/UIKit/UIViewRepresentable.swift
index 066920ab..1f3a4e7b 100644
--- a/Sources/OpenSwiftUI/Integration/Representable/UIKit/UIViewRepresentable.swift
+++ b/Sources/OpenSwiftUI/Integration/Representable/UIKit/UIViewRepresentable.swift
@@ -185,11 +185,11 @@ extension UIViewRepresentable {
     static func _modifyBridgedViewInputs(_ inputs: inout _ViewInputs) {}
     
     public static func _makeView(view: _GraphValue<Self>, inputs: _ViewInputs) -> _ViewOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     public static func _makeViewList(view: _GraphValue<Self>, inputs: _ViewListInputs) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
diff --git a/Sources/OpenSwiftUI/Integration/UIKit/UIHostingController.swift b/Sources/OpenSwiftUI/Integration/UIKit/UIHostingController.swift
index 94bb555f..e6a43c51 100644
--- a/Sources/OpenSwiftUI/Integration/UIKit/UIHostingController.swift
+++ b/Sources/OpenSwiftUI/Integration/UIKit/UIHostingController.swift
@@ -28,7 +28,7 @@ open class UIHostingController<Content> : UIViewController where Content : View
     }
     
     public required init?(coder: NSCoder) {
-        fatalError("init(coder:) must be implemented in a subclass and call super.init(coder:, rootView:)")
+        preconditionFailure("init(coder:) must be implemented in a subclass and call super.init(coder:, rootView:)")
     }
     
     func _commonInit() {
diff --git a/Sources/OpenSwiftUI/Integration/UIKit/UIHostingView.swift b/Sources/OpenSwiftUI/Integration/UIKit/UIHostingView.swift
index 93859a21..7d0eddec 100644
--- a/Sources/OpenSwiftUI/Integration/UIKit/UIHostingView.swift
+++ b/Sources/OpenSwiftUI/Integration/UIKit/UIHostingView.swift
@@ -41,7 +41,7 @@ open class _UIHostingView<Content>: UIView where Content: View {
     
     @available(*, unavailable)
     public required init?(coder _: NSCoder) {
-        fatalError("init(coder:) has not been implemented")
+        preconditionFailure("init(coder:) has not been implemented")
     }
     
     deinit {
@@ -156,40 +156,40 @@ open class _UIHostingView<Content>: UIView where Content: View {
 extension _UIHostingView: ViewRendererHost {
     package var renderingPhase: OpenSwiftUICore.ViewRenderingPhase {
         get {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         set(newValue) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
     
     package var externalUpdateCount: Int {
         get {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         set(newValue) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
     
     package func updateEnvironment() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func updateSize() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func updateSafeArea() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func updateScrollableContainerSize() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func renderDisplayList(_ list: DisplayList, asynchronously: Bool, time: Time, nextTime: Time, targetTimestamp: Time?, version: DisplayList.Version, maxVersion: DisplayList.Version) -> Time {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func addImplicitPropertiesNeedingUpdate(to _: inout ViewRendererHostProperties) {}
@@ -216,7 +216,7 @@ extension _UIHostingView: ViewRendererHost {
     }
     
     package func rootTransform() -> ViewTransform {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     public func graphDidChange() {
diff --git a/Sources/OpenSwiftUI/Scene/Core/Scene.swift b/Sources/OpenSwiftUI/Scene/Core/Scene.swift
index ecf54221..b7970107 100644
--- a/Sources/OpenSwiftUI/Scene/Core/Scene.swift
+++ b/Sources/OpenSwiftUI/Scene/Core/Scene.swift
@@ -16,6 +16,6 @@ extension Never: Scene {}
 
 extension Scene {
     func sceneBodyError() -> Never {
-        fatalError("body() should not be called on \(Self.self)")
+        preconditionFailure("body() should not be called on \(Self.self)")
     }
 }
diff --git a/Sources/OpenSwiftUI/Scene/Core/SceneBuilder.swift b/Sources/OpenSwiftUI/Scene/Core/SceneBuilder.swift
index 5f385ad5..db7bde86 100644
--- a/Sources/OpenSwiftUI/Scene/Core/SceneBuilder.swift
+++ b/Sources/OpenSwiftUI/Scene/Core/SceneBuilder.swift
@@ -44,7 +44,7 @@ extension SceneBuilder {
 //        if #available(iOS 16.1, macOS 13.0, watchOS 9.1, tvOS 16.1, *) {
 //            return LimitedAvailabilityScene(scene)
 //        } else {
-//            fatalError("Unavailable")
+//            preconditionFailure("Unavailable")
 //        }
 //    }
 }
diff --git a/Sources/OpenSwiftUI/Scene/WindowGroup.swift b/Sources/OpenSwiftUI/Scene/WindowGroup.swift
index 076dd38e..b9c5b566 100644
--- a/Sources/OpenSwiftUI/Scene/WindowGroup.swift
+++ b/Sources/OpenSwiftUI/Scene/WindowGroup.swift
@@ -47,7 +47,7 @@ public struct WindowGroup<Content>: Scene where Content: View {
 
     // FIXME
     public var body: some Scene {
-        fatalError()
+        preconditionFailure("")
     }
 
     var title: Text?
diff --git a/Sources/OpenSwiftUI/Test/TestApp.swift b/Sources/OpenSwiftUI/Test/TestApp.swift
index 415994d1..f2bfab83 100644
--- a/Sources/OpenSwiftUI/Test/TestApp.swift
+++ b/Sources/OpenSwiftUI/Test/TestApp.swift
@@ -8,10 +8,10 @@
 
 public struct _TestApp {
     public init() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     public func run() -> Never {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -21,12 +21,12 @@ extension _TestApp {
         var state: StateType
         
         init() {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         var body: some View {
             state.testView
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
     
diff --git a/Sources/OpenSwiftUI/Test/TestIDView.swift b/Sources/OpenSwiftUI/Test/TestIDView.swift
index 6d570dce..f643870b 100644
--- a/Sources/OpenSwiftUI/Test/TestIDView.swift
+++ b/Sources/OpenSwiftUI/Test/TestIDView.swift
@@ -19,7 +19,7 @@ struct TestIDView<Content, ID>: PrimitiveView, UnaryView {
     
     static func _makeView(view: _GraphValue<TestIDView<Content, ID>>, inputs: _ViewInputs) -> _ViewOutputs {
         // Use IdentifiedView here
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
diff --git a/Sources/OpenSwiftUI/Test/_Benchmark.swift b/Sources/OpenSwiftUI/Test/_Benchmark.swift
index 80ed5457..d3e89dfa 100644
--- a/Sources/OpenSwiftUI/Test/_Benchmark.swift
+++ b/Sources/OpenSwiftUI/Test/_Benchmark.swift
@@ -5,6 +5,6 @@ public protocol _Benchmark: _Test {
 extension _TestApp {
     public func runBenchmarks(_ benchmarks: [_Benchmark]) -> Never {
         let _ = RootView()
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUI/Test/_BenchmarkHost.swift b/Sources/OpenSwiftUI/Test/_BenchmarkHost.swift
index c9a05757..0c017cc1 100644
--- a/Sources/OpenSwiftUI/Test/_BenchmarkHost.swift
+++ b/Sources/OpenSwiftUI/Test/_BenchmarkHost.swift
@@ -42,7 +42,7 @@ extension _BenchmarkHost {
         }
         return end - begin
         #else
-        fatalError("Unsupported Platfrom")
+        preconditionFailure("Unsupported Platfrom")
         #endif
     }
     
diff --git a/Sources/OpenSwiftUI/Test/_PerformanceTest.swift b/Sources/OpenSwiftUI/Test/_PerformanceTest.swift
index 9a939152..73b0071f 100644
--- a/Sources/OpenSwiftUI/Test/_PerformanceTest.swift
+++ b/Sources/OpenSwiftUI/Test/_PerformanceTest.swift
@@ -26,7 +26,7 @@ extension __App {
 
 extension _TestApp {
     public func runPerformanceTests(_ tests: [_PerformanceTest]) -> Never {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -37,7 +37,7 @@ extension _BenchmarkHost {
         #elseif os(macOS)
         NSApplication.shared.startedTest(test.name)
         #else
-        fatalError("Unimplemented for other platform")
+        preconditionFailure("Unimplemented for other platform")
         #endif
     }
 
@@ -47,7 +47,7 @@ extension _BenchmarkHost {
         #elseif os(macOS)
         NSApplication.shared.finishedTest(test.name)
         #else
-        fatalError("Unimplemented for other platform")
+        preconditionFailure("Unimplemented for other platform")
         #endif
     }
 
@@ -57,7 +57,7 @@ extension _BenchmarkHost {
         #elseif os(macOS)
         NSApplication.shared.failedTest(test.name, withFailure: nil)
         #else
-        fatalError("Unimplemented for other platform")
+        preconditionFailure("Unimplemented for other platform")
         #endif
     }
 }
diff --git a/Sources/OpenSwiftUI/View/Control/Button/ButtonStyle/TODO/PlainButtonStyle.swift b/Sources/OpenSwiftUI/View/Control/Button/ButtonStyle/TODO/PlainButtonStyle.swift
index d78ffb01..3f26b323 100644
--- a/Sources/OpenSwiftUI/View/Control/Button/ButtonStyle/TODO/PlainButtonStyle.swift
+++ b/Sources/OpenSwiftUI/View/Control/Button/ButtonStyle/TODO/PlainButtonStyle.swift
@@ -12,7 +12,7 @@ public struct PlainButtonStyle: PrimitiveButtonStyle {
     public func makeBody(configuration: Configuration) -> some View {
 //        Button(configuration)
 //            .buttonStyle(buttonStyleRepresentation)
-        fatalError()
+        preconditionFailure("")
     }
 }
 
@@ -35,6 +35,6 @@ private struct PlainButtonStyleBase: ButtonStyle {
 //            configuration.label
 //        }
 //        .opacity(isEnabled ? (configuration.isPressed ? 0.75 : 1.0) : 0.5)
-        fatalError()
+        preconditionFailure("")
     }
 }
diff --git a/Sources/OpenSwiftUI/View/Control/Link/OpenURLActionKey.swift b/Sources/OpenSwiftUI/View/Control/Link/OpenURLActionKey.swift
index 31510ccc..1ad6e7d2 100644
--- a/Sources/OpenSwiftUI/View/Control/Link/OpenURLActionKey.swift
+++ b/Sources/OpenSwiftUI/View/Control/Link/OpenURLActionKey.swift
@@ -26,7 +26,7 @@ struct OpenURLActionKey: EnvironmentKey {
                 completion(error != nil)
             }
             #else
-            fatalError("Unimplemented")
+            preconditionFailure("Unimplemented")
             #endif
         },
         isDefault: true
@@ -51,7 +51,7 @@ struct OpenSensitiveURLActionKey: EnvironmentKey {
             }
             workspace.open(url, configuration: config, completionHandler: completion)
             #else
-            fatalError("Unimplemented")
+            preconditionFailure("Unimplemented")
             #endif
         },
         isDefault: true
diff --git a/Sources/OpenSwiftUI/View/Control/Slider/AnySliderStyle.swift b/Sources/OpenSwiftUI/View/Control/Slider/AnySliderStyle.swift
index d174e2c5..0258a83b 100644
--- a/Sources/OpenSwiftUI/View/Control/Slider/AnySliderStyle.swift
+++ b/Sources/OpenSwiftUI/View/Control/Slider/AnySliderStyle.swift
@@ -13,7 +13,7 @@ protocol SliderStyle {
 
 private class AnyStyleBox {
     func body(configuration _: Slider<SliderStyleLabel, SliderStyleValueLabel>) -> AnyView {
-        fatalError("")
+        preconditionFailure("")
     }
 }
 
diff --git a/Sources/OpenSwiftUI/View/Control/Slider/Slider.swift b/Sources/OpenSwiftUI/View/Control/Slider/Slider.swift
index 5df910c8..c39db015 100644
--- a/Sources/OpenSwiftUI/View/Control/Slider/Slider.swift
+++ b/Sources/OpenSwiftUI/View/Control/Slider/Slider.swift
@@ -669,7 +669,7 @@ private struct Normalizing<Value>: Projection where Value: Strideable, Value: Ha
         if let stride {
             let result = (min.distance(to: max) / stride).rounded(.down)
             guard result > 0 else {
-                fatalError("max stride must be positive")
+                preconditionFailure("max stride must be positive")
             }
             length = stride * result
             maxStrides = result
diff --git a/Sources/OpenSwiftUICore/Animation/TODO/AnimatableModifier.swift b/Sources/OpenSwiftUICore/Animation/TODO/AnimatableModifier.swift
index 401ab4fa..3f530056 100644
--- a/Sources/OpenSwiftUICore/Animation/TODO/AnimatableModifier.swift
+++ b/Sources/OpenSwiftUICore/Animation/TODO/AnimatableModifier.swift
@@ -15,7 +15,7 @@ extension AnimatableModifier {
     }
 
     public static func _makeViewList(modifier _: _GraphValue<Self>, inputs _: _ViewListInputs, body _: @escaping (_Graph, _ViewListInputs) -> _ViewListOutputs) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -25,6 +25,6 @@ extension ViewModifier where Self: Animatable {
     }
 
     public static func _makeViewList(modifier _: _GraphValue<Self>, inputs _: _ViewListInputs, body _: @escaping (_Graph, _ViewListInputs) -> _ViewListOutputs) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Animation/TODO/_AnimatableView.swift b/Sources/OpenSwiftUICore/Animation/TODO/_AnimatableView.swift
index 6e6e26bc..2196c97c 100644
--- a/Sources/OpenSwiftUICore/Animation/TODO/_AnimatableView.swift
+++ b/Sources/OpenSwiftUICore/Animation/TODO/_AnimatableView.swift
@@ -15,7 +15,7 @@ extension _AnimatableView {
     }
 
     public static func _makeViewList(view _: _GraphValue<Self>, inputs _: _ViewListInputs) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -25,6 +25,6 @@ extension View where Self: Animatable {
     }
 
     public static func _makeViewList(view _: _GraphValue<Self>, inputs _: _ViewListInputs) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Attribute/AsyncAttribute.swift b/Sources/OpenSwiftUICore/Attribute/AsyncAttribute.swift
index 233e113b..7027bd60 100644
--- a/Sources/OpenSwiftUICore/Attribute/AsyncAttribute.swift
+++ b/Sources/OpenSwiftUICore/Attribute/AsyncAttribute.swift
@@ -15,6 +15,6 @@ extension AsyncAttribute {
 
 extension Attribute {
     package func syncMainIfReferences<V>(do body: (Value) -> V) -> V {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Data/DynamicProperty/DynamicProperty.swift b/Sources/OpenSwiftUICore/Data/DynamicProperty/DynamicProperty.swift
index b35d24f2..c5208e28 100644
--- a/Sources/OpenSwiftUICore/Data/DynamicProperty/DynamicProperty.swift
+++ b/Sources/OpenSwiftUICore/Data/DynamicProperty/DynamicProperty.swift
@@ -220,7 +220,7 @@ extension BodyAccessor {
     ) -> (_GraphValue<Body>, _DynamicPropertyBuffer?) {
         #if canImport(Darwin)
         guard Body.self != Never.self else {
-            fatalError("\(Body.self) may not have Body == Never")
+            preconditionFailure("\(Body.self) may not have Body == Never")
         }
         return withUnsafeMutablePointer(to: &inputs) { inputsPointer in
             func project<Flags: RuleThreadFlags>(flags _: Flags.Type) -> (_GraphValue<Body>, _DynamicPropertyBuffer?) {
@@ -254,7 +254,7 @@ extension BodyAccessor {
             }
         }
         #else
-        fatalError("See #39")
+        preconditionFailure("See #39")
         #endif
     }
 }
diff --git a/Sources/OpenSwiftUICore/Data/DynamicProperty/DynamicPropertyBuffer.swift b/Sources/OpenSwiftUICore/Data/DynamicProperty/DynamicPropertyBuffer.swift
index 70458c60..c6f1379c 100644
--- a/Sources/OpenSwiftUICore/Data/DynamicProperty/DynamicPropertyBuffer.swift
+++ b/Sources/OpenSwiftUICore/Data/DynamicProperty/DynamicPropertyBuffer.swift
@@ -272,7 +272,7 @@ private class BoxVTableBase {
         ptr _: UnsafeMutableRawPointer,
         from _: UnsafeMutableRawPointer
     ) {
-        fatalError()
+        preconditionFailure("")
     }
     
     class func deinitialize(ptr _: UnsafeMutableRawPointer) {}
diff --git a/Sources/OpenSwiftUICore/Data/Environment/CachedEnvironment.swift b/Sources/OpenSwiftUICore/Data/Environment/CachedEnvironment.swift
index 66db15c4..99048006 100644
--- a/Sources/OpenSwiftUICore/Data/Environment/CachedEnvironment.swift
+++ b/Sources/OpenSwiftUICore/Data/Environment/CachedEnvironment.swift
@@ -38,7 +38,7 @@ package struct CachedEnvironment {
             return value
         }
         #else
-        fatalError("See #39")
+        preconditionFailure("See #39")
         #endif
     }
     
@@ -53,20 +53,20 @@ package struct CachedEnvironment {
             return attribute
         }
         #else
-        fatalError("See #39")
+        preconditionFailure("See #39")
         #endif
     }
     
     func animatedPosition(for inputs: _ViewInputs) -> Attribute<ViewOrigin> {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     func animatedSize(for inputs: _ViewInputs) -> Attribute<ViewSize> {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     func animatedCGSize(for inputs: _ViewInputs) -> Attribute<CGSize> {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     // func resolvedForegroundStyle() {}
diff --git a/Sources/OpenSwiftUICore/Data/Environment/Environment.swift b/Sources/OpenSwiftUICore/Data/Environment/Environment.swift
index 4e1255fc..4086c5f8 100644
--- a/Sources/OpenSwiftUICore/Data/Environment/Environment.swift
+++ b/Sources/OpenSwiftUICore/Data/Environment/Environment.swift
@@ -232,7 +232,7 @@ public struct Environment<Value>: DynamicProperty {
 
     @usableFromInline
     func error() -> Never {
-        fatalError("Reading Environment<\(Value.self)> outside View.body")
+        preconditionFailure("Reading Environment<\(Value.self)> outside View.body")
     }
 
     public static func _makeProperty<V>(
diff --git a/Sources/OpenSwiftUICore/Data/Location.swift b/Sources/OpenSwiftUICore/Data/Location.swift
index 12d89163..5612f07c 100644
--- a/Sources/OpenSwiftUICore/Data/Location.swift
+++ b/Sources/OpenSwiftUICore/Data/Location.swift
@@ -43,23 +43,23 @@ extension AnyLocationBase: Sendable {}
 open class AnyLocation<Value>: AnyLocationBase, @unchecked Sendable {
     @_spi(ForOpenSwiftUIOnly)
     open var wasRead: Bool {
-        get { fatalError() }
-        set { fatalError() }
+        get { preconditionFailure("") }
+        set { preconditionFailure("") }
     }
     
     @_spi(ForOpenSwiftUIOnly)
-    open func get() -> Value { fatalError() }
+    open func get() -> Value { preconditionFailure("") }
     
     @_spi(ForOpenSwiftUIOnly)
-    open func set(_ value: Value, transaction: Transaction) { fatalError() }
+    open func set(_ value: Value, transaction: Transaction) { preconditionFailure("") }
     
     @_spi(ForOpenSwiftUIOnly)
     open func projecting<P>(_ projection: P) -> AnyLocation<P.Projected> where Value == P.Base, P: Projection {
-        fatalError()
+        preconditionFailure("")
     }
     
     @_spi(ForOpenSwiftUIOnly)
-    open func update() -> (Value, Bool) { fatalError() }
+    open func update() -> (Value, Bool) { preconditionFailure("") }
     
     @_spi(ForOpenSwiftUIOnly)
     open func isEqual(to other: AnyLocation<Value>) -> Bool { self === other }
diff --git a/Sources/OpenSwiftUICore/Data/Other/2021/UnsafeAtomicLazy.swift b/Sources/OpenSwiftUICore/Data/Other/2021/UnsafeAtomicLazy.swift
index cc91d35d..f5820d16 100644
--- a/Sources/OpenSwiftUICore/Data/Other/2021/UnsafeAtomicLazy.swift
+++ b/Sources/OpenSwiftUICore/Data/Other/2021/UnsafeAtomicLazy.swift
@@ -18,7 +18,7 @@ package struct UnsafeAtomicLazy<Data>: Destroyable {
     }
     
     package func read(_ block: () -> Data) -> Data {
-        fatalError("TODO") // StrokedPath.boundingRect
+        preconditionFailure("TODO") // StrokedPath.boundingRect
     }
 
     package func destroy() {
diff --git a/Sources/OpenSwiftUICore/Data/Preference/PreferenceList.swift b/Sources/OpenSwiftUICore/Data/Preference/PreferenceList.swift
index c91432c7..dd0f94c4 100644
--- a/Sources/OpenSwiftUICore/Data/Preference/PreferenceList.swift
+++ b/Sources/OpenSwiftUICore/Data/Preference/PreferenceList.swift
@@ -178,11 +178,11 @@ private class PreferenceNode: CustomStringConvertible {
         return nil
     }
     
-    func find(from _: PreferenceNode?) -> PreferenceNode? { fatalError() }
-    func combine(from _: PreferenceNode?, next _: PreferenceNode?) -> PreferenceNode? { fatalError() }
-    func copy(next _: PreferenceNode?) -> PreferenceNode { fatalError() }
-    class var _includesRemovedValues: Bool { fatalError() }
-    var description: String { fatalError() }
+    func find(from _: PreferenceNode?) -> PreferenceNode? { preconditionFailure("") }
+    func combine(from _: PreferenceNode?, next _: PreferenceNode?) -> PreferenceNode? { preconditionFailure("") }
+    func copy(next _: PreferenceNode?) -> PreferenceNode { preconditionFailure("") }
+    class var _includesRemovedValues: Bool { preconditionFailure("") }
+    var description: String { preconditionFailure("") }
 }
 
 // MARK: - PreferenceNode
diff --git a/Sources/OpenSwiftUICore/Data/Preference/PreferencesOutputs.swift b/Sources/OpenSwiftUICore/Data/Preference/PreferencesOutputs.swift
index 0b1f316a..1c076035 100644
--- a/Sources/OpenSwiftUICore/Data/Preference/PreferencesOutputs.swift
+++ b/Sources/OpenSwiftUICore/Data/Preference/PreferencesOutputs.swift
@@ -47,14 +47,14 @@ package struct PreferencesOutputs {
             let value = self[anyKey: _AnyPreferenceKey<K>.self]
             return value.map { Attribute(identifier: $0) }
             #else
-            fatalError("See #39")
+            preconditionFailure("See #39")
             #endif
         }
         set {
             #if canImport(Darwin)
             self[anyKey: _AnyPreferenceKey<K>.self] = newValue.map { $0.identifier }
             #else
-            fatalError("See #39")
+            preconditionFailure("See #39")
             #endif
         }
     }
@@ -63,7 +63,7 @@ package struct PreferencesOutputs {
         #if canImport(Darwin)
         preferences.append(KeyValue(key: _AnyPreferenceKey<K>.self, value: value.identifier))
         #else
-        fatalError("See #39")
+        preconditionFailure("See #39")
         #endif
     }
     
diff --git a/Sources/OpenSwiftUICore/Data/Property/PropertyList.swift b/Sources/OpenSwiftUICore/Data/Property/PropertyList.swift
index 3f17925a..5ec2ed39 100644
--- a/Sources/OpenSwiftUICore/Data/Property/PropertyList.swift
+++ b/Sources/OpenSwiftUICore/Data/Property/PropertyList.swift
@@ -81,7 +81,7 @@ package struct PropertyList: CustomStringConvertible {
     }
     
     package subscript<K>(key: K.Type) -> K.Value where K: DerivedPropertyKey {
-        get { fatalError("TODO") }
+        get { preconditionFailure("TODO") }
     }
   
     @usableFromInline
@@ -126,7 +126,7 @@ package struct PropertyList: CustomStringConvertible {
     }
     
     mutating func merge(_ plist: PropertyList) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -193,18 +193,18 @@ extension PropertyList {
         }
         
         @usableFromInline
-        package var description: String { fatalError() }
+        package var description: String { preconditionFailure("") }
         
         func matches(_: Element, ignoredTypes _: inout Set<ObjectIdentifier>) -> Bool {
-            fatalError()
+            preconditionFailure("")
         }
         
         func hasMatchingValue(in _: Unmanaged<Element>?) -> Bool {
-            fatalError()
+            preconditionFailure("")
         }
         
         func copy(before _: Element?, after _: Element?) -> Element {
-            fatalError()
+            preconditionFailure("")
         }
         
         final package func byPrepending(_ element: Element?) -> Element {
diff --git a/Sources/OpenSwiftUICore/Data/Protobuf/ProtobufDecoder.swift b/Sources/OpenSwiftUICore/Data/Protobuf/ProtobufDecoder.swift
index cc2414ab..d3458195 100644
--- a/Sources/OpenSwiftUICore/Data/Protobuf/ProtobufDecoder.swift
+++ b/Sources/OpenSwiftUICore/Data/Protobuf/ProtobufDecoder.swift
@@ -471,7 +471,7 @@ extension ProtobufDecoder {
     /// - Returns: The decodable value resulting from the plist data.
     func value<T>(fromBinaryPlist data: Data, type: T.Type = T.self) throws -> T where T: Decodable {
         #if os(WASI)
-        fatalError("PropertyListDecoder is not avaiable on WASI")
+        preconditionFailure("PropertyListDecoder is not avaiable on WASI")
         #else
         let decoder = PropertyListDecoder()
         decoder.userInfo = userInfo
diff --git a/Sources/OpenSwiftUICore/Data/Protobuf/ProtobufEncoder.swift b/Sources/OpenSwiftUICore/Data/Protobuf/ProtobufEncoder.swift
index 357e0e75..304a77eb 100644
--- a/Sources/OpenSwiftUICore/Data/Protobuf/ProtobufEncoder.swift
+++ b/Sources/OpenSwiftUICore/Data/Protobuf/ProtobufEncoder.swift
@@ -415,7 +415,7 @@ extension ProtobufEncoder {
     /// - Returns: The encoded binary plist data.
     func binaryPlistData<T>(for value: T) throws -> Data where T: Encodable {
         #if os(WASI)
-        fatalError("PropertyListEncoder is not avaiable on WASI")
+        preconditionFailure("PropertyListEncoder is not avaiable on WASI")
         #else
         let encoder = PropertyListEncoder()
         encoder.outputFormat = .binary
diff --git a/Sources/OpenSwiftUICore/Data/State/StoredLocation.swift b/Sources/OpenSwiftUICore/Data/State/StoredLocation.swift
index 7d82be0f..688f5c27 100644
--- a/Sources/OpenSwiftUICore/Data/State/StoredLocation.swift
+++ b/Sources/OpenSwiftUICore/Data/State/StoredLocation.swift
@@ -55,15 +55,15 @@ package class StoredLocationBase<Value>: AnyLocation<Value>, Location, @unchecke
     // MARK: - abstract method
     
     fileprivate var isUpdating: Bool {
-        fatalError("abstract")
+        preconditionFailure("abstract")
     }
     
     fileprivate func commit(transaction: Transaction, mutation: BeginUpdate) {
-        fatalError("abstract")
+        preconditionFailure("abstract")
     }
     
     fileprivate func notifyObservers() {
-        fatalError("abstract")
+        preconditionFailure("abstract")
     }
     
     // MARK: - AnyLocation
diff --git a/Sources/OpenSwiftUICore/Data/StrongHash.swift b/Sources/OpenSwiftUICore/Data/StrongHash.swift
index cbe02884..02d15765 100644
--- a/Sources/OpenSwiftUICore/Data/StrongHash.swift
+++ b/Sources/OpenSwiftUICore/Data/StrongHash.swift
@@ -150,7 +150,7 @@ package struct StrongHasher {
     package mutating func combineType(_ type: any Any.Type) {
 //        let signature = OGTypeGetSignature
 //        CC_SHA1_Update(&state, signature, 20)
-        fatalError("Blocked by latest OGTypeGetSignature")
+        preconditionFailure("Blocked by latest OGTypeGetSignature")
     }
 }
 
diff --git a/Sources/OpenSwiftUICore/Data/Transaction/Transaction.swift b/Sources/OpenSwiftUICore/Data/Transaction/Transaction.swift
index 0e7d6e86..2030c8ad 100644
--- a/Sources/OpenSwiftUICore/Data/Transaction/Transaction.swift
+++ b/Sources/OpenSwiftUICore/Data/Transaction/Transaction.swift
@@ -74,7 +74,7 @@ public struct Transaction {
     package var isEmpty: Bool { plist.isEmpty }
     
     package func mayConcatenate(with other: Transaction) -> Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     @_transparent
@@ -99,11 +99,11 @@ public struct Transaction {
     }
     
     package var current: Transaction {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func forEach<K>(keyType: K.Type, _ body: (K.Value, inout Bool) -> Void) where K: TransactionKey {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     // FIXME: TO BE REMOVED
diff --git a/Sources/OpenSwiftUICore/Data/Update.swift b/Sources/OpenSwiftUICore/Data/Update.swift
index 30b19b7f..dd887fa7 100644
--- a/Sources/OpenSwiftUICore/Data/Update.swift
+++ b/Sources/OpenSwiftUICore/Data/Update.swift
@@ -60,7 +60,7 @@ package enum Update {
             return
         }
         guard isOwner else {
-            fatalError("OpenSwiftUI is active without having taken its own lock - missing Update.ensure()?")
+            preconditionFailure("OpenSwiftUI is active without having taken its own lock - missing Update.ensure()?")
         }
     }
     
@@ -111,7 +111,7 @@ package enum Update {
                 }
             }
             #else
-            fatalError("See #39")
+            preconditionFailure("See #39")
             #endif
         }
         #endif
@@ -152,7 +152,7 @@ package enum Update {
                         action()
                         let newDepth = depth
                         guard newDepth == oldDepth else {
-                            fatalError("Action caused unbalanced updates.")
+                            preconditionFailure("Action caused unbalanced updates.")
                         }
                     }
                 }
diff --git a/Sources/OpenSwiftUICore/Graph/GraphHost.swift b/Sources/OpenSwiftUICore/Graph/GraphHost.swift
index db0f8ae2..8f255028 100644
--- a/Sources/OpenSwiftUICore/Graph/GraphHost.swift
+++ b/Sources/OpenSwiftUICore/Graph/GraphHost.swift
@@ -149,10 +149,10 @@ open class GraphHost: CustomReflectable {
         } else if let currentSubgraph = Subgraph.current {
             currentSubgraph.graph.graphHost()
         } else {
-            fatalError("no current graph host")
+            preconditionFailure("no current graph host")
         }
         #else
-        fatalError("Compiler issue on Linux. See #39")
+        preconditionFailure("Compiler issue on Linux. See #39")
         #endif
     }
     
@@ -232,7 +232,7 @@ open class GraphHost: CustomReflectable {
             return result
         }
         #else
-        fatalError("See #39")
+        preconditionFailure("See #39")
         #endif
     }
     
@@ -282,7 +282,7 @@ extension GraphHost {
         guard isInstantiated else {
             return
         }
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package final func uninstantiate() {
@@ -329,7 +329,7 @@ extension GraphHost {
     }
     
     package final func updateRemovedState() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     // MARK: - GraphHost + Transaction
@@ -341,7 +341,7 @@ extension GraphHost {
         style: _GraphMutation_Style = .deferred,
         mayDeferUpdate: Bool = true
     ) where T: GraphMutation {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package final func asyncTransaction(
@@ -392,30 +392,30 @@ extension GraphHost {
         pendingTransactions = []
         for _ in transactions {
             instantiateIfNeeded()
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         graphDelegate?.graphDidChange()
         mayDeferUpdate = true
     }
 
     package final func runTransaction(_ transaction: Transaction? = nil, do body: () -> Void) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package final func runTransaction() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package final var needsTransaction: Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package final func startTransactionUpdate() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 
     package final func finishTransactionUpdate(in subgraph: Subgraph, postUpdate: (_ again: Bool) -> Void = { _ in }) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -424,7 +424,7 @@ extension GraphHost {
     private static var pendingGlobalTransactions: [GlobalTransaction] = []
 
     private static func flushGlobalTransactions() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package static func globalTransaction<T>(
@@ -433,7 +433,7 @@ extension GraphHost {
         mutation: T,
         hostProvider: any TransactionHostProvider
     ) where T: GraphMutation {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -596,5 +596,5 @@ private var blockedGraphHosts: [Unmanaged<GraphHost>] = []
 private let waitingForPreviewThunks = EnvironmentHelper.bool(for: "XCODE_RUNNING_FOR_PREVIEWS")
 
 public func __previewThunksHaveFinishedLoading() {
-    fatalError("TODO")
+    preconditionFailure("TODO")
 }
diff --git a/Sources/OpenSwiftUICore/Graph/GraphInputs.swift b/Sources/OpenSwiftUICore/Graph/GraphInputs.swift
index 4b3bf686..48d16cb8 100644
--- a/Sources/OpenSwiftUICore/Graph/GraphInputs.swift
+++ b/Sources/OpenSwiftUICore/Graph/GraphInputs.swift
@@ -22,7 +22,7 @@ extension GraphInput {
     }
     
     package static func makeReusable(indirectMap: IndirectAttributeMap, value: inout Value) {
-        fatalError("Reusable graph inputs must implement all reuse methods.")
+        preconditionFailure("Reusable graph inputs must implement all reuse methods.")
     }
   
     @inlinable
@@ -103,7 +103,7 @@ public struct _GraphInputs {
             transaction: Attribute(identifier: .nil)
         )
         #else
-        fatalError("See #39")
+        preconditionFailure("See #39")
         #endif
     }
     
@@ -152,15 +152,15 @@ public struct _GraphInputs {
     }
     
     package mutating func `import`(_ src: _GraphInputs) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package mutating func merge(_ src: _GraphInputs) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package mutating func merge(_ src: _GraphInputs, ignoringPhase: Bool) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func mapEnvironment<T>(_ keyPath: KeyPath<EnvironmentValues, T>) -> Attribute<T> {
@@ -169,11 +169,11 @@ public struct _GraphInputs {
     
     package mutating func copyCaches() {
         // Blocked by cachedEnvironment
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     package mutating func resetCaches() {
         // Blocked cachedEnvironment
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package mutating func append<T, U>(_ newValue: U, to _: T.Type) where T: GraphInput, T.Value == Stack<U> {
@@ -306,6 +306,6 @@ extension _GraphInputs {
 //        var newInputs = self
 //        newInputs.cachedEnvironment = MutableBox(cachedEnvironment.wrappedValue)
 //        return newInputs
-        fatalError("TO BE REMOVED")
+        preconditionFailure("TO BE REMOVED")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Graphic/Color/Color.swift b/Sources/OpenSwiftUICore/Graphic/Color/Color.swift
index 59f16bac..b2c00a9f 100644
--- a/Sources/OpenSwiftUICore/Graphic/Color/Color.swift
+++ b/Sources/OpenSwiftUICore/Graphic/Color/Color.swift
@@ -112,7 +112,7 @@ extension Color {
 }
 
 package func HSBToRGB(hue: Double, saturation: Double, brightness: Double) -> (red: Double, green: Double, blue: Double) {
-    fatalError("TODO")
+    preconditionFailure("TODO")
 }
 
 
@@ -167,7 +167,7 @@ extension ColorProvider {
     package var kitColor: AnyObject? { nil }
     package var colorDescription: String { String(describing: self) }
     package func opacity(at level: Int, environment: EnvironmentValues) -> Float {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
diff --git a/Sources/OpenSwiftUICore/Graphic/Color/ColorMatrix.swift b/Sources/OpenSwiftUICore/Graphic/Color/ColorMatrix.swift
index 3bdeb8f2..27465937 100644
--- a/Sources/OpenSwiftUICore/Graphic/Color/ColorMatrix.swift
+++ b/Sources/OpenSwiftUICore/Graphic/Color/ColorMatrix.swift
@@ -57,7 +57,7 @@ public struct _ColorMatrix: Equatable, Codable {
     
     public init(color: Color, in environment: EnvironmentValues) {
         // Blocked by Color
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package init(_ m: ColorMatrix) {
@@ -170,7 +170,7 @@ extension _ColorMatrix {
     }
     
     package init?(_ filter: GraphicsFilter, premultiplied: Bool = false) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package init(colorMultiply c: Color.Resolved, premultiplied: Bool = false) {
diff --git a/Sources/OpenSwiftUICore/Graphic/Color/ColorResolved.swift b/Sources/OpenSwiftUICore/Graphic/Color/ColorResolved.swift
index a5bb2652..8347f66c 100644
--- a/Sources/OpenSwiftUICore/Graphic/Color/ColorResolved.swift
+++ b/Sources/OpenSwiftUICore/Graphic/Color/ColorResolved.swift
@@ -30,14 +30,14 @@ extension Color {
         }
         
 //        package func over(_ s: Resolved) -> Color.Resolved {
-//            fatalError("TODO")
+//            preconditionFailure("TODO")
 //        }
     }
     
     package struct ResolvedVibrant: Equatable {
         package var scale: Float
         package var bias: (Float, Float, Float)
-        // package var colorMatrix: _ColorMatrix { fatalError("TODO") }
+        // package var colorMatrix: _ColorMatrix { preconditionFailure("TODO") }
         
         package static func == (lhs: ResolvedVibrant, rhs: ResolvedVibrant) -> Bool {
             lhs.scale == rhs.scale && lhs.bias == rhs.bias
@@ -64,7 +64,7 @@ extension Color.Resolved/*: ResolvedPaint*/ {
 
 extension Color.Resolved: ShapeStyle/*, PrimitiveShapeStyle*/ {
     public func _apply(to shape: inout _ShapeStyle_Shape) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     public typealias Resolved = Never
@@ -94,7 +94,7 @@ extension Color.Resolved : Animatable {
         get {
             if Self.legacyInterpolation {
                 // ResolvedGradient.Color.Space.convertIn(self)
-                fatalError("TODO")
+                preconditionFailure("TODO")
             } else {
                 let factor: Float = 128.0
                 return AnimatablePair(linearRed * factor, AnimatablePair(linearGreen * factor, AnimatablePair(linearBlue * factor, opacity * factor)))
@@ -105,7 +105,7 @@ extension Color.Resolved : Animatable {
             let factor: Float = 0.0078125
             if Self.legacyInterpolation {
                 // ResolvedGradient.Color.Space.convertOut(self)
-                fatalError("TODO")
+                preconditionFailure("TODO")
             } else {
                 linearRed = newValue.first * factor
                 linearGreen = newValue.second.first * factor
diff --git a/Sources/OpenSwiftUICore/Graphic/ResolvedPaint.swift b/Sources/OpenSwiftUICore/Graphic/ResolvedPaint.swift
index 5c3b1629..0983a8d8 100644
--- a/Sources/OpenSwiftUICore/Graphic/ResolvedPaint.swift
+++ b/Sources/OpenSwiftUICore/Graphic/ResolvedPaint.swift
@@ -7,7 +7,7 @@
 
 package class AnyResolvedPaint: Equatable {
     package static func == (lhs: AnyResolvedPaint, rhs: AnyResolvedPaint) -> Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
diff --git a/Sources/OpenSwiftUICore/Layout/LayoutFundamentals/Stack/HVStack.swift b/Sources/OpenSwiftUICore/Layout/LayoutFundamentals/Stack/HVStack.swift
index c78ff394..4c44f1ed 100644
--- a/Sources/OpenSwiftUICore/Layout/LayoutFundamentals/Stack/HVStack.swift
+++ b/Sources/OpenSwiftUICore/Layout/LayoutFundamentals/Stack/HVStack.swift
@@ -18,6 +18,6 @@ public struct HStack<Content: View>: PrimitiveView {
     var _tree: _VariadicView.Tree<_HStackLayout, Content>
 
     public static func _makeView(view _: _GraphValue<HStack<Content>>, inputs _: _ViewInputs) -> _ViewOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Layout/LayoutFundamentals/internal/LayoutComputer.swift b/Sources/OpenSwiftUICore/Layout/LayoutFundamentals/internal/LayoutComputer.swift
index 607e3c15..d496f549 100644
--- a/Sources/OpenSwiftUICore/Layout/LayoutFundamentals/internal/LayoutComputer.swift
+++ b/Sources/OpenSwiftUICore/Layout/LayoutFundamentals/internal/LayoutComputer.swift
@@ -30,7 +30,7 @@ extension LayoutComputer {
         func layoutPriority() -> Double { .zero }
         func ignoresAutomaticPadding() -> Bool { false }
         func requiresSpacingProjection() -> Bool { false }
-        func spacing() -> Spacing { fatalError() }
+        func spacing() -> Spacing { preconditionFailure("") }
         func lengthThatFits(_ size: _ProposedSize, in axis: Axis) -> CGFloat {
             let result = sizeThatFits(size)
             return switch axis {
@@ -39,8 +39,8 @@ extension LayoutComputer {
             }
         }
 
-        func sizeThatFits(_: _ProposedSize) -> CGSize { fatalError() }
-        func childGeometries(at _: ViewSize, origin _: CGPoint) -> [ViewGeometry] { fatalError() }
+        func sizeThatFits(_: _ProposedSize) -> CGSize { preconditionFailure("") }
+        func childGeometries(at _: ViewSize, origin _: CGPoint) -> [ViewGeometry] { preconditionFailure("") }
         func explicitAlignment(_: AlignmentKey, at _: ViewSize) -> CGFloat? { nil }
     }
 }
diff --git a/Sources/OpenSwiftUICore/Log/Logging.swift b/Sources/OpenSwiftUICore/Log/Logging.swift
index 63bbebb1..8c605f5b 100644
--- a/Sources/OpenSwiftUICore/Log/Logging.swift
+++ b/Sources/OpenSwiftUICore/Log/Logging.swift
@@ -165,13 +165,18 @@ extension Log: Sendable {}
 @_transparent
 package func precondition(_ condition: @autoclosure () -> Bool, _ message: @autoclosure () -> String, file: StaticString = #fileID, line: UInt = #line) {
     guard condition() else {
-        Swift.preconditionFailure(message(), file: file, line: line)
+        preconditionFailure(message(), file: file, line: line)
     }
 }
 
 @_transparent
 package func preconditionFailure(_ message: @autoclosure () -> String, file: StaticString, line: UInt) -> Never {
-    Swift.preconditionFailure(message(), file: file, line: line)
+    #if DEBUG && OPENSWIFTUI_DEVELOPMENT
+    if message() == "TODO" {
+        print("💣 Hit unimplemented part of OpenSwiftUI at \(file):\(line).\nConsider adding a plain implementation to avoid crash.")
+    }
+    #endif
+    Swift.fatalError(message(), file: file, line: line)
 }
 
 @_transparent
diff --git a/Sources/OpenSwiftUICore/Modifier/AppearanceActionModifier.swift b/Sources/OpenSwiftUICore/Modifier/AppearanceActionModifier.swift
index ff027d51..047def13 100644
--- a/Sources/OpenSwiftUICore/Modifier/AppearanceActionModifier.swift
+++ b/Sources/OpenSwiftUICore/Modifier/AppearanceActionModifier.swift
@@ -38,7 +38,7 @@ public struct _AppearanceActionModifier: PrimitiveViewModifier {
         inputs: _ViewListInputs,
         body: @escaping (_Graph, _ViewListInputs) -> _ViewListOutputs
     ) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -91,7 +91,7 @@ extension AppearanceEffect: StatefulRule {
         lastValue = modifier
         appeared()
         #else
-        fatalError("See #39")
+        preconditionFailure("See #39")
         #endif
     }
 }
diff --git a/Sources/OpenSwiftUICore/Modifier/ViewModifier/CustomViewModifier.swift b/Sources/OpenSwiftUICore/Modifier/ViewModifier/CustomViewModifier.swift
index d0ca6df3..c4fe047c 100644
--- a/Sources/OpenSwiftUICore/Modifier/ViewModifier/CustomViewModifier.swift
+++ b/Sources/OpenSwiftUICore/Modifier/ViewModifier/CustomViewModifier.swift
@@ -39,14 +39,14 @@ extension ViewModifier {
         inputs: _ViewListInputs,
         body: @escaping (_Graph, _ViewListInputs) -> _ViewListOutputs
     ) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     static func viewListCount(
         inputs: _ViewListCountInputs,
         body: (_ViewListCountInputs) -> Int?
     ) -> Int? {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     private static func makeBody(
@@ -60,7 +60,7 @@ extension ViewModifier {
             let accessor = ModifierBodyAccessor<Self>()
             return accessor.makeBody(container: modifier, inputs: &inputs, fields: fields)
         default:
-            fatalError("view modifiers must be value types:  \(Self.self)")
+            preconditionFailure("view modifiers must be value types:  \(Self.self)")
         }
     }
 }
@@ -95,7 +95,7 @@ public struct _ViewModifier_Content<Modifier: ViewModifier>: PrimitiveView {
         case let .view(makeViewBody):
             return makeViewBody(_Graph(), inputs)
         case let .list(makeViewListBody):
-            fatalError("TODO: \(String(describing: makeViewListBody))")
+            preconditionFailure("TODO: \(String(describing: makeViewListBody))")
         }
     }
     
@@ -103,14 +103,14 @@ public struct _ViewModifier_Content<Modifier: ViewModifier>: PrimitiveView {
         view: _GraphValue<Self>,
         inputs: _ViewListInputs
     ) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     public static func _viewListCount(
         inputs: _ViewListCountInputs,
         body: (_ViewListCountInputs) -> Int?
     ) -> Int? {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
diff --git a/Sources/OpenSwiftUICore/Modifier/ViewModifier/ViewModifier.swift b/Sources/OpenSwiftUICore/Modifier/ViewModifier/ViewModifier.swift
index bc0fbaa1..bc7fe379 100644
--- a/Sources/OpenSwiftUICore/Modifier/ViewModifier/ViewModifier.swift
+++ b/Sources/OpenSwiftUICore/Modifier/ViewModifier/ViewModifier.swift
@@ -160,6 +160,6 @@ extension ViewModifier where Self: _GraphInputsModifier, Body == Never {
 
 extension ViewModifier {
     func bodyError() -> Never {
-        fatalError("body() should not be called on \(Self.self)")
+        preconditionFailure("body() should not be called on \(Self.self)")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.GraphicsRenderer.swift b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.GraphicsRenderer.swift
index 22aefc1c..58e736ad 100644
--- a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.GraphicsRenderer.swift
+++ b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.GraphicsRenderer.swift
@@ -42,31 +42,31 @@ extension DisplayList {
         package var platformViewMode: DisplayList.GraphicsRenderer.PlatformViewMode
         
         package init(platformViewMode: DisplayList.GraphicsRenderer.PlatformViewMode) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package func render(at time: Time, do body: () -> Void) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package func renderDisplayList(_ list: DisplayList, at time: Time, in ctx: inout GraphicsContext) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package func render(list: DisplayList, in ctx: inout GraphicsContext) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package func render(item: DisplayList.Item, in ctx: inout GraphicsContext) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package func drawImplicitLayer(in ctx: inout GraphicsContext, content: (inout GraphicsContext) -> Void) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package func renderPlatformView(_ view: AnyObject?, in ctx: GraphicsContext, size: CGSize, viewType: any Any.Type) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
 }
diff --git a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.ViewRenderer.swift b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.ViewRenderer.swift
index 6bace908..29cc3cd3 100644
--- a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.ViewRenderer.swift
+++ b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.ViewRenderer.swift
@@ -129,7 +129,7 @@ extension DisplayList {
         var lastContentsScale: CGFloat
         
         init(platform: DisplayList.ViewUpdater.Platform, host: ViewRendererHost?, rootView: AnyObject, options: _RendererConfiguration.RasterizationOptions) {
-            fatalError()
+            preconditionFailure("")
         }
         
         var exportedObject: AnyObject? {
@@ -137,19 +137,19 @@ extension DisplayList {
         }
         
         func render(rootView: AnyObject, from list: DisplayList, time: Time, version: DisplayList.Version, maxVersion: DisplayList.Version, environment: DisplayList.ViewRenderer.Environment) -> Time {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         func renderAsync(to list: DisplayList, time: Time, targetTimestamp: Time?, version: DisplayList.Version, maxVersion: DisplayList.Version) -> Time? {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         func destroy(rootView: AnyObject) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         var viewCacheIsEmpty: Bool {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
 }
diff --git a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.ViewUpdater.swift b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.ViewUpdater.swift
index 76adaf0c..38778ee7 100644
--- a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.ViewUpdater.swift
+++ b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.ViewUpdater.swift
@@ -9,7 +9,7 @@ extension DisplayList {
     // FIXME
     final package class ViewUpdater: ViewRendererBase {
         init() {
-            fatalError()
+            preconditionFailure("")
         }
         
         init(platform: Platform, exportedObject: AnyObject? = nil, viewCacheIsEmpty: Bool) {
diff --git a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.swift b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.swift
index b9b07f37..38788f90 100644
--- a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.swift
+++ b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList.swift
@@ -89,11 +89,11 @@ package struct DisplayList: Equatable {
     }
     
     package mutating func append(_ item: Item) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package mutating func append(contentsOf other: DisplayList) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }    
 }
 
@@ -365,16 +365,16 @@ extension DisplayList {
         }
         
         package mutating func skip(list: DisplayList) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package mutating func skip(item: Item) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package mutating func skip(effect: Effect) {
             
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package func assertItem(_ item: Item) {}
diff --git a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList_StableIdentity.swift b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList_StableIdentity.swift
index 5f73b45c..bab24361 100644
--- a/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList_StableIdentity.swift
+++ b/Sources/OpenSwiftUICore/Render/DisplayList/DisplayList_StableIdentity.swift
@@ -41,7 +41,7 @@ final package class _DisplayList_StableIdentityRoot {
         if let map {
             return map[index]
         } else {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
 }
@@ -81,17 +81,17 @@ extension _DisplayList_StableIdentity: ProtobufMessage {
     }
     
     package init(from decoder: inout ProtobufDecoder) throws {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
 extension _DisplayList_StableIdentityMap: ProtobufMessage {
     package func encode(to encoder: inout ProtobufEncoder) throws {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package init(from decoder: inout ProtobufDecoder) throws {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -145,7 +145,7 @@ extension _GraphInputs {
 
 package func makeStableTypeData(_ type: any Any.Type) -> StrongHash {
     // OGTypeGetSignature
-    fatalError("TODO")
+    preconditionFailure("TODO")
 }
 
 package func makeStableIDData<ID>(from id: ID) -> StrongHash? {
diff --git a/Sources/OpenSwiftUICore/Render/PlatformViewDefinition.swift b/Sources/OpenSwiftUICore/Render/PlatformViewDefinition.swift
index cc8888e3..f1046e97 100644
--- a/Sources/OpenSwiftUICore/Render/PlatformViewDefinition.swift
+++ b/Sources/OpenSwiftUICore/Render/PlatformViewDefinition.swift
@@ -48,18 +48,18 @@ open class PlatformViewDefinition: @unchecked Sendable {
     }
   
     open class var system: PlatformViewDefinition.System { .init(base: .swiftUIView) }
-    open class func makeView(kind: PlatformViewDefinition.ViewKind) -> AnyObject { fatalError() }
+    open class func makeView(kind: PlatformViewDefinition.ViewKind) -> AnyObject { preconditionFailure("") }
     #if canImport(Darwin)
-    open class func makeLayerView(type: CALayer.Type, kind: PlatformViewDefinition.ViewKind) -> AnyObject { fatalError() }
+    open class func makeLayerView(type: CALayer.Type, kind: PlatformViewDefinition.ViewKind) -> AnyObject { preconditionFailure("") }
     #endif
-    open class func makePlatformView(view: AnyObject, kind: PlatformViewDefinition.ViewKind) { fatalError() }
-    // open class func makeDrawingView(options: PlatformDrawableOptions) -> any PlatformDrawable { fatalError() }
-    open class func setPath(_ path: Path, shapeView: AnyObject) { fatalError() }
-    open class func setProjectionTransform(_ transform: ProjectionTransform, projectionView: AnyObject) { fatalError() }
-    open class func getRBLayer(drawingView: AnyObject) -> AnyObject? { fatalError() }
-    open class func setIgnoresEvents(_ state: Bool, of view: AnyObject) { fatalError() }
-    open class func setAllowsWindowActivationEvents(_ value: Bool?, for view: AnyObject) { fatalError() }
-    open class func setHitTestsAsOpaque(_ value: Bool, for view: AnyObject) { fatalError() }
+    open class func makePlatformView(view: AnyObject, kind: PlatformViewDefinition.ViewKind) { preconditionFailure("") }
+    // open class func makeDrawingView(options: PlatformDrawableOptions) -> any PlatformDrawable { preconditionFailure("") }
+    open class func setPath(_ path: Path, shapeView: AnyObject) { preconditionFailure("") }
+    open class func setProjectionTransform(_ transform: ProjectionTransform, projectionView: AnyObject) { preconditionFailure("") }
+    open class func getRBLayer(drawingView: AnyObject) -> AnyObject? { preconditionFailure("") }
+    open class func setIgnoresEvents(_ state: Bool, of view: AnyObject) { preconditionFailure("") }
+    open class func setAllowsWindowActivationEvents(_ value: Bool?, for view: AnyObject) { preconditionFailure("") }
+    open class func setHitTestsAsOpaque(_ value: Bool, for view: AnyObject) { preconditionFailure("") }
 }
 
 extension DisplayList.ViewUpdater {
@@ -86,7 +86,7 @@ extension DisplayList.GraphicsRenderer {
             layer.bounds = CGRect(origin: .zero, size: size)
             layer.layoutIfNeeded()
         }
-        fatalError("Blocked by GraphicsContext")
+        preconditionFailure("Blocked by GraphicsContext")
         // ctx.drawLayer
     }
     #endif
diff --git a/Sources/OpenSwiftUICore/Shape/Path/FixedRoundedRect.swift b/Sources/OpenSwiftUICore/Shape/Path/FixedRoundedRect.swift
index b92df697..a8bf0077 100644
--- a/Sources/OpenSwiftUICore/Shape/Path/FixedRoundedRect.swift
+++ b/Sources/OpenSwiftUICore/Shape/Path/FixedRoundedRect.swift
@@ -26,6 +26,6 @@ struct FixedRoundedRect: Equatable {
     }
     
     func distance(to point: CGPoint) -> CGFloat {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Shape/Path/Path.swift b/Sources/OpenSwiftUICore/Shape/Path/Path.swift
index ce629516..44ae9511 100644
--- a/Sources/OpenSwiftUICore/Shape/Path/Path.swift
+++ b/Sources/OpenSwiftUICore/Shape/Path/Path.swift
@@ -147,7 +147,7 @@ public struct Path/*: Equatable, LosslessStringConvertible*/ {
     ///
     @available(iOS 16.0, macOS 13.0, tvOS 16.0, watchOS 9.0, *)
     public init(roundedRect rect: CGRect, cornerRadii: RectangleCornerRadii, style: RoundedCornerStyle = .continuous) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     #endif
     
@@ -216,19 +216,19 @@ public struct Path/*: Equatable, LosslessStringConvertible*/ {
     /// A description of the path that may be used to recreate the path
     /// via `init?(_:)`.
     public var description: String {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 
     #if canImport(CoreGraphics)
     /// An immutable path representing the elements in the path.
     public var cgPath: CGPath {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     #endif
     
     /// A Boolean value indicating whether the path contains zero elements.
     public var isEmpty: Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 
     /// A rectangle containing all path segments.
@@ -237,7 +237,7 @@ public struct Path/*: Equatable, LosslessStringConvertible*/ {
     /// in the path but not including control points for Bézier
     /// curves.
     public var boundingRect: CGRect {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     /// Returns true if the path contains a specified point.
@@ -245,18 +245,18 @@ public struct Path/*: Equatable, LosslessStringConvertible*/ {
     /// If `eoFill` is true, this method uses the even-odd rule to define which
     /// points are inside the path. Otherwise, it uses the non-zero rule.
     public func contains(_ p: CGPoint, eoFill: Bool = false) -> Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     /// Calls `body` with each element in the path.
     public func forEach(_ body: (Path.Element) -> Void) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 
     /// Returns a stroked copy of the path using `style` to define how the
     /// stroked outline is created.
     public func strokedPath(_ style: StrokeStyle) -> Path {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 
     /// Returns a partial copy of the path.
@@ -265,7 +265,7 @@ public struct Path/*: Equatable, LosslessStringConvertible*/ {
     /// which must be fractions between zero and one defining points
     /// linearly-interpolated along the path.
     public func trimmedPath(from: CGFloat, to: CGFloat) -> Path {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -290,11 +290,11 @@ extension Path {
         }
         
         init(_ path: CGPath) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         init(_ mutablePath: CGMutablePath) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         // FIXME
diff --git a/Sources/OpenSwiftUICore/Shape/Rectangle.swift b/Sources/OpenSwiftUICore/Shape/Rectangle.swift
index c00f066b..df410d94 100644
--- a/Sources/OpenSwiftUICore/Shape/Rectangle.swift
+++ b/Sources/OpenSwiftUICore/Shape/Rectangle.swift
@@ -4,7 +4,7 @@ public import Foundation
 @frozen
 public struct Rectangle: Shape {
     public func path(in rect: CGRect) -> Path {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 
     /// Creates a new rectangle shape.
diff --git a/Sources/OpenSwiftUICore/Shape/RoundedRectangle.swift b/Sources/OpenSwiftUICore/Shape/RoundedRectangle.swift
index b2cc786b..9b4b1556 100644
--- a/Sources/OpenSwiftUICore/Shape/RoundedRectangle.swift
+++ b/Sources/OpenSwiftUICore/Shape/RoundedRectangle.swift
@@ -18,7 +18,7 @@ public struct RoundedRectangle: Shape {
     }
     
     public func path(in rect: CGRect) -> Path {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     public var animatableData: CGSize.AnimatableData {
         get { cornerSize.animatableData }
diff --git a/Sources/OpenSwiftUICore/Shape/ShapeStyle/BlendMode.swift b/Sources/OpenSwiftUICore/Shape/ShapeStyle/BlendMode.swift
index 4d8799b5..9bf921c9 100644
--- a/Sources/OpenSwiftUICore/Shape/ShapeStyle/BlendMode.swift
+++ b/Sources/OpenSwiftUICore/Shape/ShapeStyle/BlendMode.swift
@@ -116,7 +116,7 @@ public struct _BlendModeShapeStyle<Style>: ShapeStyle, PrimitiveShapeStyle where
                     shape.result = .preparedText(.foregroundKeyColor)
                 }
             default:
-                fatalError("TODO")
+                preconditionFailure("TODO")
 //            case resolveStyle(name: _ShapeStyle_Name, levels: Range<Int>):
 //                
 //                
diff --git a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ForegroundStyleModifier.swift b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ForegroundStyleModifier.swift
index 14ca29c3..01cedb4a 100644
--- a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ForegroundStyleModifier.swift
+++ b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ForegroundStyleModifier.swift
@@ -187,7 +187,7 @@ public struct _ForegroundStyleModifier<Style>: PrimitiveViewModifier, ViewInputs
     }
     
     public nonisolated static func _makeViewInputs(modifier: _GraphValue<_ForegroundStyleModifier<Style>>, inputs: inout _ViewInputs) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     public typealias Body = Never
@@ -211,7 +211,7 @@ extension _ForegroundStyleModifier: Sendable {}
     }
 
     nonisolated public static func _makeViewInputs(modifier: _GraphValue<_ForegroundStyleModifier2<S1, S2>>, inputs: inout _ViewInputs) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 
     public typealias Body = Never
@@ -239,7 +239,7 @@ public struct _ForegroundStyleModifier3<S1, S2, S3>: PrimitiveViewModifier, View
     }
 
     nonisolated public static func _makeViewInputs(modifier: _GraphValue<_ForegroundStyleModifier3<S1, S2, S3>>, inputs: inout _ViewInputs) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 
     @available(iOS 15.0, tvOS 15.0, watchOS 8.0, macOS 12.0, *)
diff --git a/Sources/OpenSwiftUICore/Shape/ShapeStyle/LegacyContentStyle.swift b/Sources/OpenSwiftUICore/Shape/ShapeStyle/LegacyContentStyle.swift
index 6aa94179..e3faee81 100644
--- a/Sources/OpenSwiftUICore/Shape/ShapeStyle/LegacyContentStyle.swift
+++ b/Sources/OpenSwiftUICore/Shape/ShapeStyle/LegacyContentStyle.swift
@@ -8,13 +8,13 @@
 package struct LegacyContentStyle: ShapeStyle, PrimitiveShapeStyle {
     package static let sharedPrimary: AnyShapeStyle = {
         // Blocked by Color
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }()
     
     package var id: ContentStyle.ID
     package var color: Color
     
     package func _apply(to shape: inout _ShapeStyle_Shape) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyle.swift b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyle.swift
index b91636da..63869408 100644
--- a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyle.swift
+++ b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyle.swift
@@ -120,13 +120,13 @@ extension Never: ShapeStyle {
     public typealias Resolved = Never
     
     public static func _makeView<S>(view: _GraphValue<_ShapeView<S, Never>>, inputs: _ViewInputs) -> _ViewOutputs where S: Shape{
-        fatalError()
+        preconditionFailure("")
     }
 }
 
 extension ShapeStyle where Resolved == Never {
     public func resolve(in: EnvironmentValues) -> Self.Resolved {
-        fatalError()
+        preconditionFailure("")
     }
     
     public static func _apply(to type: inout _ShapeStyle_ShapeType) {}
diff --git a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStylePack.swift b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStylePack.swift
index 44913ae8..2d2249df 100644
--- a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStylePack.swift
+++ b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStylePack.swift
@@ -136,7 +136,7 @@ package struct _ShapeStyle_Pack: Equatable {
         var baseLevel: UInt8
         
         init(pack: _ShapeStyle_Pack, name: _ShapeStyle_Name) {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package var startIndex: Int {
@@ -144,38 +144,38 @@ package struct _ShapeStyle_Pack: Equatable {
         }
         
         package var endIndex: Int {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         package subscript(level: Int) -> _ShapeStyle_Pack.Style {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
     
     package mutating func modify(name: _ShapeStyle_Name, levels: Range<Int>, _ modifier: (inout _ShapeStyle_Pack.Style) -> Void) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package mutating func adjustLevelIndices(of name: _ShapeStyle_Name, by offset: Int) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package mutating func createOpacities(count: Int, name: _ShapeStyle_Name, environment: EnvironmentValues) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func isClear(name: _ShapeStyle_Name) -> Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package subscript(colorName: String) -> Color.Resolved? {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
 extension _ShapeStyle_Pack.Slice {
     package var allColors: Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -192,23 +192,23 @@ extension _ShapeStyle_Pack.Style {
     }
     
     package var ignoresBackdrop: Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package mutating func applyOpacity(_ opacity: Float) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func applyingOpacity(_ opacity: Float) -> _ShapeStyle_Pack.Style {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package mutating func applyBlend(_ blend: GraphicsBlendMode) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package var color: Color.Resolved? {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
diff --git a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyleResolver.swift b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyleResolver.swift
index 5022d56d..83196cd0 100644
--- a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyleResolver.swift
+++ b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyleResolver.swift
@@ -26,15 +26,15 @@ package struct ShapeStyleResolver<Style>: StatefulRule, AsyncAttribute, Observed
         animationsDisabled: Bool
     // helper: AnimatableAttributeHelper<_ShapeStyle_Pack>
     ) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package mutating func updateValue() {
-        fatalError()
+        preconditionFailure("")
     }
     
     package func destroy() {
         // Blocked by _ShapeStyle_Pack
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyleShape.swift b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyleShape.swift
index 56b79085..0bd82e96 100644
--- a/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyleShape.swift
+++ b/Sources/OpenSwiftUICore/Shape/ShapeStyle/ShapeStyleShape.swift
@@ -72,21 +72,21 @@ public struct _ShapeStyle_Shape {
     
     package func opacity(at level: Int) -> Float {
         // Blocked by Color
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func opacity(for color: Color, at level: Int) -> Float {
         // Blocked by Color
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     package func applyingOpacity(at level: Int, to color: Color) -> Color {
         // Blocked by Color
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func applyingOpacity(at level: Int, to color: Color.Resolved) -> Color.Resolved {
         // Blocked by Color
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package var currentForegroundStyle: AnyShapeStyle? {
diff --git a/Sources/OpenSwiftUICore/Shape/ShapeView.swift b/Sources/OpenSwiftUICore/Shape/ShapeView.swift
index d1c6affe..de1870f8 100644
--- a/Sources/OpenSwiftUICore/Shape/ShapeView.swift
+++ b/Sources/OpenSwiftUICore/Shape/ShapeView.swift
@@ -19,6 +19,6 @@ public struct _ShapeView<Content, Style>: /*ShapeStyledLeafView, */UnaryView, Pr
     }
 
     public static func _makeView(view: _GraphValue<_ShapeView<Content, Style>>, inputs: _ViewInputs) -> _ViewOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUICore/Text/Font/TODO/Font.swift b/Sources/OpenSwiftUICore/Text/Font/TODO/Font.swift
index 5b1373d6..d3c390b0 100644
--- a/Sources/OpenSwiftUICore/Text/Font/TODO/Font.swift
+++ b/Sources/OpenSwiftUICore/Text/Font/TODO/Font.swift
@@ -28,12 +28,12 @@ public struct Font: Hashable {
 package class AnyFontBox: Hashable {
     @usableFromInline
     package func hash(into _: inout Hasher) {
-        fatalError()
+        preconditionFailure("")
     }
 
     @usableFromInline
     package static func == (_: AnyFontBox, _: AnyFontBox) -> Bool {
-        fatalError()
+        preconditionFailure("")
     }
 }
 
diff --git a/Sources/OpenSwiftUICore/Util/ThreadUtils.swift b/Sources/OpenSwiftUICore/Util/ThreadUtils.swift
index bc09e570..4470d0cf 100644
--- a/Sources/OpenSwiftUICore/Util/ThreadUtils.swift
+++ b/Sources/OpenSwiftUICore/Util/ThreadUtils.swift
@@ -69,8 +69,6 @@ package func onMainThread(do body: @escaping () -> Void) {
 
 package func mainThreadPrecondition() {
     #if !os(WASI)
-    guard Thread.isMainThread else {
-        fatalError("calling into OpenSwiftUI on a non-main thread is not supported")
-    }
+    precondition(Thread.isMainThread, "calling into OpenSwiftUI on a non-main thread is not supported")
     #endif
 }
diff --git a/Sources/OpenSwiftUICore/View/AnyView.swift b/Sources/OpenSwiftUICore/View/AnyView.swift
index 92777664..1e60b918 100644
--- a/Sources/OpenSwiftUICore/View/AnyView.swift
+++ b/Sources/OpenSwiftUICore/View/AnyView.swift
@@ -69,12 +69,12 @@ public struct AnyView: PrimitiveView {
         }
         return outputs
         #else
-        fatalError("See #39")
+        preconditionFailure("See #39")
         #endif
     }
     
     public static func _makeViewList(view: _GraphValue<Self>, inputs: _ViewListInputs) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -86,25 +86,25 @@ class AnyViewStorageBase {
         self.id = id
     }
     
-    fileprivate var type: Any.Type { fatalError() }
-    fileprivate var canTransition: Bool { fatalError() }
-    fileprivate func matches(_ other: AnyViewStorageBase) -> Bool { fatalError() }
+    fileprivate var type: Any.Type { preconditionFailure("") }
+    fileprivate var canTransition: Bool { preconditionFailure("") }
+    fileprivate func matches(_ other: AnyViewStorageBase) -> Bool { preconditionFailure("") }
     fileprivate func makeChild(
         uniqueId: UInt32,
         container: Attribute<AnyViewInfo>,
         inputs: _ViewInputs
     ) -> _ViewOutputs {
-        fatalError()
+        preconditionFailure("")
     }
-    func child<Value>() -> Value { fatalError() }
+    func child<Value>() -> Value { preconditionFailure("") }
     fileprivate func makeViewList(
         view: _GraphValue<AnyView>,
         inputs: _ViewListInputs
     ) -> _ViewListOutputs {
-        fatalError()
+        preconditionFailure("")
     }
     fileprivate func visitContent<Vistor: ViewVisitor>(_ visitor: inout Vistor) {
-        fatalError()
+        preconditionFailure("")
     }
 }
 
@@ -204,7 +204,7 @@ private struct AnyViewContainer: StatefulRule, AsyncAttribute {
             return AnyViewInfo(item: storage, subgraph: childGraph, uniqueID: uniqueId)
         }
         #else
-        fatalError("#See #39")
+        preconditionFailure("#See #39")
         #endif
     }
     
@@ -261,7 +261,7 @@ private struct AnyViewList: StatefulRule, AsyncAttribute {
     typealias Value = AnyView // FIXME
     
     func updateValue() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     final class Item: _ViewList_Subgraph {
diff --git a/Sources/OpenSwiftUICore/View/CoreGlue/CoreGlue.swift b/Sources/OpenSwiftUICore/View/CoreGlue/CoreGlue.swift
index 5435dae1..a6300de6 100644
--- a/Sources/OpenSwiftUICore/View/CoreGlue/CoreGlue.swift
+++ b/Sources/OpenSwiftUICore/View/CoreGlue/CoreGlue.swift
@@ -17,7 +17,7 @@ open class CoreGlue: NSObject {
     
     
     open func makeDefaultLayoutComputer() -> MakeDefaultLayoutComputerResult {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
diff --git a/Sources/OpenSwiftUICore/View/CustomView.swift b/Sources/OpenSwiftUICore/View/CustomView.swift
index 036d4bdb..d6c06d4c 100644
--- a/Sources/OpenSwiftUICore/View/CustomView.swift
+++ b/Sources/OpenSwiftUICore/View/CustomView.swift
@@ -52,7 +52,7 @@ extension View {
             let accessor = ViewBodyAccessor<Self>()
             return accessor.makeBody(container: view, inputs: &inputs, fields: fields)
         default:
-            fatalError("views must be value types (either a struct or an enum); \(Self.self) is a class.")
+            preconditionFailure("views must be value types (either a struct or an enum); \(Self.self) is a class.")
         }
     }
 }
diff --git a/Sources/OpenSwiftUICore/View/Debug/ViewDebug.swift b/Sources/OpenSwiftUICore/View/Debug/ViewDebug.swift
index 8b947a76..ec224fe7 100644
--- a/Sources/OpenSwiftUICore/View/Debug/ViewDebug.swift
+++ b/Sources/OpenSwiftUICore/View/Debug/ViewDebug.swift
@@ -82,7 +82,7 @@ extension View {
         view: _GraphValue<Self>,
         inputs: _ViewInputs
     ) -> _ViewOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     @inline(__always)
diff --git a/Sources/OpenSwiftUICore/View/Graph/ViewGraph.swift b/Sources/OpenSwiftUICore/View/Graph/ViewGraph.swift
index bc380472..ef741d96 100644
--- a/Sources/OpenSwiftUICore/View/Graph/ViewGraph.swift
+++ b/Sources/OpenSwiftUICore/View/Graph/ViewGraph.swift
@@ -37,7 +37,7 @@ package final class ViewGraph: GraphHost {
                 return
             }
             guard requestedOutputs.contains(.layout) else {
-                fatalError("Cannot use sizeThatFits without layout output")
+                preconditionFailure("Cannot use sizeThatFits without layout output")
             }
         }
     }
@@ -83,7 +83,7 @@ package final class ViewGraph: GraphHost {
         super.init(data: data)
         OGSubgraph.current = nil
         #else
-        fatalError("TOOD")
+        preconditionFailure("TOOD")
         #endif
     }
     
@@ -151,7 +151,7 @@ package final class ViewGraph: GraphHost {
 //                delegate?.focusDidChange()
             }
         } else {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         mainUpdates &-= 1
         #endif
diff --git a/Sources/OpenSwiftUICore/View/Graph/ViewRendererHost.swift b/Sources/OpenSwiftUICore/View/Graph/ViewRendererHost.swift
index 10e17fc8..bcfdc64c 100644
--- a/Sources/OpenSwiftUICore/View/Graph/ViewRendererHost.swift
+++ b/Sources/OpenSwiftUICore/View/Graph/ViewRendererHost.swift
@@ -79,7 +79,7 @@ extension ViewRendererHost {
     package func invalidate() {
         // viewGraph.delegate = nil
         // TODO: Signpost.viewHost
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
 //    package static func makeRootView<V>(_ view: V) -> ModifiedContent<V, HitTestBindingModifier> where V: View
@@ -100,14 +100,14 @@ extension ViewRendererHost {
     
     @_spi(ForOpenSwiftUIOnly)
     public func graphDidChange() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func didRender() {}
     
     @_spi(ForOpenSwiftUIOnly)
     public func preferencesDidChange() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func invalidateProperties(_ props: ViewRendererHostProperties, mayDeferUpdate: Bool = true) {
@@ -140,7 +140,7 @@ extension ViewRendererHost {
     }
     
     package func updateTransform() {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func render(interval: Double = 0, updateDisplayList: Bool = true, targetTimestamp: Time? = nil) {
@@ -167,34 +167,34 @@ extension ViewRendererHost {
     }
     
     package func renderAsync(interval: Double = 0, targetTimestamp: Time?) -> Time? {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     package func advanceTimeForTest(interval: Double) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     @_spi(Private)
     public func preferenceValue<K>(_ key: K.Type) -> K.Value where K: HostPreferenceKey {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
-    package func idealSize() -> CGSize { fatalError("TODO") }
+    package func idealSize() -> CGSize { preconditionFailure("TODO") }
     
     package func sizeThatFits(_ proposal: _ProposedSize) -> CGSize {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     package func explicitAlignment(of guide: HorizontalAlignment, at size: CGSize) -> CGFloat? {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     package func explicitAlignment(of guide: VerticalAlignment, at size: CGSize) -> CGFloat? {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     package func alignment(of guide: HorizontalAlignment, at size: CGSize) -> CGFloat {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     package func alignment(of guide: VerticalAlignment, at size: CGSize) -> CGFloat {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     package var centersRootView: Bool {
         get { viewGraph.centersRootView }
@@ -202,14 +202,14 @@ extension ViewRendererHost {
     }
     
 //    package var responderNode: ResponderNode? {
-//        fatalError("TODO")
+//        preconditionFailure("TODO")
 //    }
     
     package var isRootHost: Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
-    private var enclosingHosts: [ViewRendererHost] { fatalError("TODO") }
-    package func performExternalUpdate(_ update: () -> Void) { fatalError("TODO") }
+    private var enclosingHosts: [ViewRendererHost] { preconditionFailure("TODO") }
+    package func performExternalUpdate(_ update: () -> Void) { preconditionFailure("TODO") }
     package func updateFocusedItem() {}
     package func updateFocusedValues() {}
     package func updateFocusStore() {}
@@ -265,7 +265,7 @@ extension EnvironmentValues {
 
 extension ViewRendererHost {
     package func rootContentPath(kind: ContentShapeKinds) -> Path {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
diff --git a/Sources/OpenSwiftUICore/View/Input/ViewInputs.swift b/Sources/OpenSwiftUICore/View/Input/ViewInputs.swift
index 14b5c509..cadd1346 100644
--- a/Sources/OpenSwiftUICore/View/Input/ViewInputs.swift
+++ b/Sources/OpenSwiftUICore/View/Input/ViewInputs.swift
@@ -170,7 +170,7 @@ public struct _ViewInputs {
             hostPreferenceKeys: Attribute(identifier: .nil)
         )
         #else
-        fatalError("See #39")
+        preconditionFailure("See #39")
         #endif
     }
     
diff --git a/Sources/OpenSwiftUICore/View/InterfaceIdiom/InterfaceIdiomPredicate.swift b/Sources/OpenSwiftUICore/View/InterfaceIdiom/InterfaceIdiomPredicate.swift
index ec6c9381..5c304405 100644
--- a/Sources/OpenSwiftUICore/View/InterfaceIdiom/InterfaceIdiomPredicate.swift
+++ b/Sources/OpenSwiftUICore/View/InterfaceIdiom/InterfaceIdiomPredicate.swift
@@ -33,7 +33,7 @@ extension _GraphInputs {
         #elseif os(iOS) || os(visionOS)
         AnyInterfaceIdiom(.phone)
         #else
-        fatalError("TODO")
+        preconditionFailure("TODO")
         #endif
     }
 }
diff --git a/Sources/OpenSwiftUICore/View/Trait/ViewTraitCollection.swift b/Sources/OpenSwiftUICore/View/Trait/ViewTraitCollection.swift
index cbcf7ed0..0c427b94 100644
--- a/Sources/OpenSwiftUICore/View/Trait/ViewTraitCollection.swift
+++ b/Sources/OpenSwiftUICore/View/Trait/ViewTraitCollection.swift
@@ -53,11 +53,11 @@ package struct ViewTraitCollection {
     }
     
 //    func insertInteraction(for: OnInsertInteraction.Strategy) -> OnInsertInteraction? {
-//        fatalError("TODO")
+//        preconditionFailure("TODO")
 //    }
 //    
 //    var optionalTransition: AnyTransition? {
-//        fatalError("TODO")
+//        preconditionFailure("TODO")
 //    }
 }
 
diff --git a/Sources/OpenSwiftUICore/View/Variadic/VariadicView.swift b/Sources/OpenSwiftUICore/View/Variadic/VariadicView.swift
index 16df934a..48813cbd 100644
--- a/Sources/OpenSwiftUICore/View/Variadic/VariadicView.swift
+++ b/Sources/OpenSwiftUICore/View/Variadic/VariadicView.swift
@@ -38,7 +38,7 @@ public enum _VariadicView {
 
 extension _VariadicView_ViewRoot {
     func bodyError() -> Never {
-        fatalError("body() should not be called on \(Self.self)")
+        preconditionFailure("body() should not be called on \(Self.self)")
     }
 }
 
diff --git a/Sources/OpenSwiftUICore/View/Variadic/VariadicView_Children.swift b/Sources/OpenSwiftUICore/View/Variadic/VariadicView_Children.swift
index 8de8ed05..e2206eec 100644
--- a/Sources/OpenSwiftUICore/View/Variadic/VariadicView_Children.swift
+++ b/Sources/OpenSwiftUICore/View/Variadic/VariadicView_Children.swift
@@ -22,11 +22,11 @@ extension _VariadicView_Children: RandomAccessCollection {
         
         public var id: AnyHashable {
 //            view.viewID
-            fatalError("TODO")
+            preconditionFailure("TODO")
 
         }
         public func id<ID>(as _: ID.Type = ID.self) -> ID? where ID : Hashable {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         public subscript<Trait: _ViewTraitKey>(key: Trait.Type) -> Trait.Value {
@@ -35,22 +35,22 @@ extension _VariadicView_Children: RandomAccessCollection {
         }
 
         public static func _makeView(view: _GraphValue<_VariadicView_Children.Element>, inputs: _ViewInputs) -> _ViewOutputs {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
     
     public var startIndex: Int {
-        fatalError("TODO")
+        preconditionFailure("TODO")
 
 //      get
     }
     public var endIndex: Int {
-        fatalError("TODO")
+        preconditionFailure("TODO")
 
 //      get
     }
     public subscript(index: Int) -> _VariadicView_Children.Element {
-        fatalError("TODO")
+        preconditionFailure("TODO")
 
 //      get
     }
@@ -63,7 +63,7 @@ extension _VariadicView_Children {
         @Attribute var children: _VariadicView_Children
         
         var value: Value {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
 }
diff --git a/Sources/OpenSwiftUICore/View/Variadic/VariadicView_ViewRoot.swift b/Sources/OpenSwiftUICore/View/Variadic/VariadicView_ViewRoot.swift
index 71c7153f..e8849ece 100644
--- a/Sources/OpenSwiftUICore/View/Variadic/VariadicView_ViewRoot.swift
+++ b/Sources/OpenSwiftUICore/View/Variadic/VariadicView_ViewRoot.swift
@@ -42,7 +42,7 @@ extension _VariadicView_ViewRoot {
         inputs: _ViewInputs,
         body: (_Graph, _ViewInputs) -> _ViewListOutputs
     ) -> _ViewOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     public static func _makeViewList(
@@ -50,7 +50,7 @@ extension _VariadicView_ViewRoot {
         inputs: _ViewListInputs,
         body: @escaping (_Graph, _ViewListInputs) -> _ViewListOutputs
     ) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     public static func _viewListCount(inputs: _ViewListCountInputs) -> Int? {
diff --git a/Sources/OpenSwiftUICore/View/View.swift b/Sources/OpenSwiftUICore/View/View.swift
index 7cf718a4..4117036b 100644
--- a/Sources/OpenSwiftUICore/View/View.swift
+++ b/Sources/OpenSwiftUICore/View/View.swift
@@ -103,6 +103,6 @@ extension Never: View {
 
 extension View {
     package func bodyError() -> Never {
-        fatalError("body() should not be called on \(Self.self)")
+        preconditionFailure("body() should not be called on \(Self.self)")
     }
 }
diff --git a/Sources/OpenSwiftUICore/View/ViewAlias.swift b/Sources/OpenSwiftUICore/View/ViewAlias.swift
index c207ec71..8829a92b 100644
--- a/Sources/OpenSwiftUICore/View/ViewAlias.swift
+++ b/Sources/OpenSwiftUICore/View/ViewAlias.swift
@@ -30,7 +30,7 @@ private struct StaticSourceWriter<Alias: ViewAlias, Source: View>: PrimitiveView
     var source: Source
 
     static func _makeInputs(modifier: _GraphValue<StaticSourceWriter<Alias, Source>>, inputs: inout _GraphInputs) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -38,6 +38,6 @@ private struct OptionalSourceWriter<Alias: ViewAlias, Source: View>: PrimitiveVi
     var source: Source?
 
     static func _makeInputs(modifier: _GraphValue<OptionalSourceWriter<Alias, Source>>, inputs: inout _GraphInputs) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
diff --git a/Sources/OpenSwiftUICore/View/ViewList.swift b/Sources/OpenSwiftUICore/View/ViewList.swift
index d40eac1f..0ca7a3fb 100644
--- a/Sources/OpenSwiftUICore/View/ViewList.swift
+++ b/Sources/OpenSwiftUICore/View/ViewList.swift
@@ -76,7 +76,7 @@ public struct _ViewListOutputs {
     }
     
     private static func staticList(_ elements: _ViewList_Elements, inputs: _ViewListInputs, staticCount: Int) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -87,7 +87,7 @@ extension _ViewListOutputs {
     }
     
     package static func nonEmptyParentViewList(inputs: _ViewListInputs) -> _ViewListOutputs {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -129,9 +129,9 @@ package struct _ViewList_ID {
     
     package class Views {
         let isDataDependent: Bool
-        var endIndex: Int { fatalError() }
-        subscript(index: Int) -> _ViewList_ID { fatalError() }
-        func isEqual(to other: Views) -> Bool { fatalError() }
+        var endIndex: Int { preconditionFailure("") }
+        subscript(index: Int) -> _ViewList_ID { preconditionFailure("") }
+        func isEqual(to other: Views) -> Bool { preconditionFailure("") }
         init(isDataDependent: Bool) {
             self.isDataDependent = isDataDependent
         }
@@ -180,11 +180,11 @@ package struct _ViewList_ID {
         }
         
         override subscript(index: Int) -> _ViewList_ID {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
         
         override func isEqual(to other: _ViewList_ID.Views) -> Bool {
-            fatalError("TODO")
+            preconditionFailure("TODO")
         }
     }
     
@@ -333,7 +333,7 @@ private struct UnaryElements<Value>: _ViewList_Elements {
         indirectMap: _ViewList_IndirectMap?,
         body: Body
     ) -> (_ViewOutputs?, Bool) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     func tryToReuseElement(
@@ -343,7 +343,7 @@ private struct UnaryElements<Value>: _ViewList_Elements {
         indirectMap: _ViewList_IndirectMap,
         testOnly: Bool
     ) -> Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -398,15 +398,15 @@ private struct SubgraphElements: _ViewList_Elements {
     let subgraph: _ViewList_Subgraph
     
     var count: Int {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     func makeElements(from start: inout Int, inputs: _ViewInputs, indirectMap: _ViewList_IndirectMap?, body: (_ViewInputs, @escaping MakeElement) -> (_ViewOutputs?, Bool)) -> (_ViewOutputs?, Bool) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     func tryToReuseElement(at index: Int, by other: any _ViewList_Elements, at otherIndex: Int, indirectMap: _ViewList_IndirectMap, testOnly: Bool) -> Bool {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
@@ -466,7 +466,7 @@ struct _ViewList_IteratorStyle: Equatable {
     var value: UInt
     
     func alignToPreviousGranularityMultiple(_ value: inout Int) {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
 }
 
diff --git a/Tests/OpenSwiftUICoreTests/Data/Protobuf/ProtobufTestHelper.swift b/Tests/OpenSwiftUICoreTests/Data/Protobuf/ProtobufTestHelper.swift
index 85baef69..24ccc328 100644
--- a/Tests/OpenSwiftUICoreTests/Data/Protobuf/ProtobufTestHelper.swift
+++ b/Tests/OpenSwiftUICoreTests/Data/Protobuf/ProtobufTestHelper.swift
@@ -376,7 +376,7 @@ struct EquatableCodableMessage<T>: ProtobufMessage where T: Codable, T: Equatabl
     }
     
     init(from decoder: inout ProtobufDecoder) throws {
-        fatalError("TODO")
+        preconditionFailure("TODO")
     }
     
     func encode(to encoder: inout ProtobufEncoder) throws {
diff --git a/Tests/OpenSwiftUI_SPITests/Overlay/CoreGraphics/CoreGraphicsContextTests.swift b/Tests/OpenSwiftUI_SPITests/Overlay/CoreGraphics/CoreGraphicsContextTests.swift
index ceeb40d0..bc4c795e 100644
--- a/Tests/OpenSwiftUI_SPITests/Overlay/CoreGraphics/CoreGraphicsContextTests.swift
+++ b/Tests/OpenSwiftUI_SPITests/Overlay/CoreGraphics/CoreGraphicsContextTests.swift
@@ -27,7 +27,7 @@ struct CoreGraphicsContextTests {
             space: colorSpace,
             bitmapInfo: bitmapInfo
         ) else {
-            fatalError("Could not create CGContext")
+            preconditionFailure("Could not create CGContext")
         }
 
         let context = CoreGraphicsContext(cgContext: cgContext)
diff --git a/Tests/OpenSwiftUI_SPITests/Shims/DyldPrivateTests.swift b/Tests/OpenSwiftUI_SPITests/Shims/DyldPrivateTests.swift
index 721f6d5e..cc05fb16 100644
--- a/Tests/OpenSwiftUI_SPITests/Shims/DyldPrivateTests.swift
+++ b/Tests/OpenSwiftUI_SPITests/Shims/DyldPrivateTests.swift
@@ -65,7 +65,7 @@ struct DyldPrivateTests {
             )) == true)
         }
         #else
-        fatalError("Unsupported Darwin platform")
+        preconditionFailure("Unsupported Darwin platform")
         #endif
 
 #else
@@ -96,7 +96,7 @@ struct DyldPrivateTests {
             #elseif os(visionOS)
             #expect(platform == .XROS_SIMULATOR)
             #else
-            fatalError("Unsupported Darwin simulator platform")
+            preconditionFailure("Unsupported Darwin simulator platform")
             #endif
         #else
             #if os(iOS)
@@ -110,7 +110,7 @@ struct DyldPrivateTests {
             #elseif os(visionOS)
             #expect(platform == .XROS)
             #else
-            fatalError("Unsupported Darwin platform")
+            preconditionFailure("Unsupported Darwin platform")
             #endif
         #endif
 #else