Add type hint to fetch method

Author: roanutil

Examples/Relationships/RelationshipsExample/RelationshipsExample/FileCabinetsView.swift

@@ -87,8 +87,7 @@ final class FileCabinetsViewModel {
 
     @Sendable
     func loadFileCabinets() async {
-        let result: Result<[FileCabinet], CoreDataError> = await repository.fetch(Self.fetchRequest)
-        switch result {
+        switch await repository.fetch(Self.fetchRequest, as: FileCabinet.self) {
         case let .success(success):
             state.fileCabinets = success
         case let .failure(error):

Sources/CoreDataRepository/CoreDataRepository+Fetch.swift

@@ -11,9 +11,10 @@ import Foundation
 
 extension CoreDataRepository {
     /// Fetch items from the store with a ``NSFetchRequest``.
-    public func fetch<Model: UnmanagedModel>(_ request: NSFetchRequest<Model.ManagedModel>) async
-        -> Result<[Model], CoreDataError>
-    {
+    public func fetch<Model: UnmanagedModel>(
+        _ request: NSFetchRequest<Model.ManagedModel>,
+        as _: Model.Type
+    ) async -> Result<[Model], CoreDataError> {
         await context.performInChild { fetchContext in
             try fetchContext.fetch(request).map(Model.init(managed:))
         }

Tests/CoreDataRepositoryTests/FetchRepositoryTests.swift

@@ -41,8 +41,7 @@ final class FetchRepositoryTests: CoreDataXCTestCase {
     }
 
     func testFetchSuccess() async throws {
-        let result: Result<[Movie], CoreDataError> = try await repository().fetch(fetchRequest)
-        switch result {
+        switch try await repository().fetch(fetchRequest, as: Movie.self) {
         case let .success(movies):
             XCTAssertEqual(movies.count, 5, "Result items count should match expectation")
             XCTAssertEqual(movies, expectedMovies, "Result items should match expectations")