RELEASE: backcompat for generic cast in single-fetch types (#9948)

.changeset/gorgeous-toys-flash.md

@@ -0,0 +1,5 @@
+---
+"remix": patch
+---
+
+REMOVE: bump prerelease version

packages/remix-server-runtime/single-fetch.ts

@@ -418,23 +418,24 @@ type Serialize<T> =
 
   undefined
 
-type Fn = (...args: any[]) => unknown;
-
 // Backwards-compatible type for Remix v2 where json/defer still use the old types,
 // and only non-json/defer returns use the new types.  This allows for incremental
 // migration of loaders to return naked objects.  In the next major version,
 // json/defer will be removed so everything will use the new simplified typings.
 // prettier-ignore
-export type SerializeFrom<T extends Fn> =
-  Parameters<T> extends [ClientLoaderFunctionArgs | ClientActionFunctionArgs] ?
-    Awaited<ReturnType<T>> extends TypedResponse<infer U> ? Jsonify<U> :
-    Awaited<ReturnType<T>> extends TypedDeferredData<infer U> ? U :
-    Awaited<ReturnType<T>>
+export type SerializeFrom<T> =
+  T extends (...args: infer Args) => infer Return ?
+    Args extends [ClientLoaderFunctionArgs | ClientActionFunctionArgs] ?
+      Awaited<Return> extends TypedResponse<infer U> ? Jsonify<U> :
+      Awaited<Return> extends TypedDeferredData<infer U> ? U :
+      Awaited<Return>
+    :
+    Awaited<Return> extends TypedResponse<infer U> ? Jsonify<U> :
+    Awaited<Return> extends TypedDeferredData<infer U> ? Serialize<U> :
+    Awaited<Return> extends DataWithResponseInit<infer D> ? Serialize<D> :
+    Serialize<Awaited<ReturnType<T>>>
   :
-  Awaited<ReturnType<T>> extends TypedResponse<infer U> ? Jsonify<U> :
-  Awaited<ReturnType<T>> extends TypedDeferredData<infer U> ? Serialize<U> :
-  Awaited<ReturnType<T>> extends DataWithResponseInit<infer D> ? Serialize<D> :
-  Serialize<Awaited<ReturnType<T>>>;
+  T
 
 type ServerLoader<T> = (args: LoaderFunctionArgs) => T;
 type ClientLoader<T> = (args: ClientLoaderFunctionArgs) => T;
@@ -604,4 +605,7 @@ type _tests = [
 
   Expect<Equal<Pretty<SerializeFrom<ServerLoader<TypedResponse<{a: string, b: Date}>>>>, { a: string, b: string }>>,
   Expect<Equal<Pretty<SerializeFrom<ServerLoader<TypedDeferredData<{a: string, b: Promise<Date>}>>>>, { a: string, b: Promise<Date> }>>,
+
+  // non-function backcompat
+  Expect<Equal<SerializeFrom<{a: string, b: Date}>, {a: string, b: Date}>>
 ]