Features I would like to see from Swift and its core ecosystem

Swift Wish List.md

Swift Wish List

Features I would like to see from Swift and its core ecosystem, to make it a robust and ergonomic language for all use cases.

• ❌ = Unimplemented / no accepted design
• 📜 = Manifesto / vision
• ⚾️ = Pitch / discussion
• 💍 = Proposal
• ⛔️ = Partially implemented / preview / gated / awaiting fuller implementation
• ⚠️ = In active review
• ✅ = Accepted / implemented, but not yet available in Swift 6.3.2
• ☑️ = Available in Swift 6.3.2, the current stable Swift toolchain

Language Features

• ☑️ Variadic generics
  • ☑️ Value and type parameter packs
  • ☑️ Variadic generic types
  • ☑️ Pack iteration

Systems Programming

• ⛔️ Memory ownership system
  • ☑️ Parameter ownership modifiers: borrowing / consuming
  • ☑️ Noncopyable structs and enums
  • ☑️ Noncopyable generics
  • ☑️ Nonescapable types
  • ☑️ Span
  • ☑️ Standard Library primitives for nonescapable types
  • ⚠️ Iterable for noncopyable / nonescapable iteration
• ☑️ Integer generic parameters
• ☑️ InlineArray

Concurrency

• ☑️ async / await
• ☑️ async let structured concurrency bindings
• ☑️ Actors
  • ☑️ Global actors
  • ☑️ Distributed actors
• ☑️ async program entry points
• ☑️ Concurrency in top-level code
• ☑️ AsyncSequence
  • ☑️ AsyncStream
• ☑️ Effectful properties (async and throws)
• ☑️ Strict concurrency checking / data-race safety in Swift 6 language mode
• ☑️ Approachable concurrency
  • ☑️ Default main actor isolation
  • ☑️ Async functions inherit caller isolation by default
  • ☑️ Explicit @concurrent opt-out

Protocols, Existentials, & Generics

• ☑️ Existentials for protocols with Self or associated type constraints
• ☑️ Existential types using any
• ☑️ Opaque types using some
• ☑️ Lightweight same-type requirements for primary associated types
• ☑️ Primary Associated Types in the Standard Library
• ☑️ Primary associated type syntax in structural positions:
  • ☑️ Existential types, e.g. func test(_: any Collection<String>)
  • ☑️ Opaque types, e.g. func evenValues(in: some Collection<Int>) -> some Collection<Int>
  • ☑️ Implicitly opened existentials

Strings

• ☑️ Regex Type
• ☑️ Regex builder DSL
• ☑️ Regex syntax
• ☑️ Regex literals

Optionals

• ☑️ Concise syntax for duplicate identifiers in if let bindings

Domain Specific Languages

• ☑️ Result builders
• ☑️ Implicit memberwise initializer
• ☑️ Result builder let declarations

Metaprogramming & Reflection

• ☑️ Property wrappers
• ⛔️ First-class macro system
  • ☑️ Expression macros
  • ☑️ Attached macros
  • ☑️ Freestanding declaration macros
  • ☑️ Extension macros
  • ☑️ SwiftSyntax-based macro plugins
  • ❌ Pattern-matching macros
  • ⚾️ A way to define default protocol implementations as a macro
  • ❌ Stable helper attributes for macro-defined attributes

Modules

• ☑️ Module name selectors / fully qualified module syntax, e.g. ModuleA::getValue()

Interoperability & Platform Support

• ☑️ C++ interoperability
  • ☑️ Import C++ types and APIs into Swift
  • ☑️ Use Swift from C++ in supported configurations
• ☑️ C interoperability improvements
  • ☑️ @c
  • ☑️ @implementation
• ☑️ Upstream WebAssembly support
• ☑️ JavaScript interoperability
• ☑️ Java interoperability
• ☑️ Official Swift SDK for Android

Ecosystem Features

• ☑️ Swift Testing, an official Swift-native testing library
  • ☑️ Included in official Swift toolchains
  • ☑️ Integrated with Swift Package Manager
  • ☑️ Exit testing
  • ☑️ Attachments
  • ☑️ Warning issues
  • ☑️ Test cancellation
  • ☑️ Image attachments
• ☑️ swiftly, an official Swift toolchain manager
• ☑️ Official HTML documentation generation tool
  • ☑️ DocC
  • ☑️ Static HTML output
  • ☑️ Markdown and code-annotation improvements
• ☑️ Subprocess, a cross-platform process-spawning library
• ⛔️ Swift Build
  • ☑️ Open source build engine
  • ⛔️ SwiftPM integration preview

Standard Library & Foundation

• ☑️ Clock, Instant, and Duration time types for the Standard Library
• ⛔️ Open source Foundation implementation / Foundation reimplementation
• ⛔️ Replace Foundation with modern APIs, split into individually importable submodules
  • ☑️ Foundation Essentials
  • ☑️ Foundation Internationalization
  • ☑️ Typed NotificationCenter messages

Swift Package Manager

• ☑️ Package editor commands
• ☑️ Package traits
• ☑️ Extensible build tools
• ☑️ Additional package plugin APIs
• ☑️ Package Manager command plugins for swift package
• ☑️ swift package show-traits
• ⛔️ Swift Build integration

SwiftNIO & Networking

• ☑️ async / await support
• ❌ QUIC and HTTP/3 support in SwiftNIO
• 📜 Networking workgroup / Swift networking vision