Feature → concurrency: asynchronous function aka the async/await pattern
Feature: Declaration and type attributes
Feature → attributes: the @autoclosure type attribute
The @available attribute and availability checking in general
Feature → statements: Availability condition
Feature → identifiers: Backticked identifiers. Allows using reserved words as identifiers
Area → standard library: The `BidirectionalCollection` protocol
Feature → patterns: Binding patterns
Area → utils → build-script: Bootstrapping schemes
Feature → casting: type bridging
A deviation from expected or documented behavior. Also: expected but undesirable behavior.
Errors when building the toolchain, not regular Swift code
Area → utils: The build script
Feature: Interoperability with C
Feature: Interoperability with C++
Feature → c++ interop: c++ to swift
Feature → expressions: Call expressions
Resolution → bug: Cannot reproduce due to incomplete or inaccessible test case
Feature → closures: Closure capture lists
Feature: explicit casting (is, as, as? and as!)
Feature → attributes: The @_cdecl attribute
Area → standard library: The `Character` type