Move platform requirements to availability annotations

Package.swift

@@ -4,12 +4,6 @@ import PackageDescription
 
 let package = Package(
   name: "swift-async-algorithms",
-  platforms: [
-    .macOS("10.15"),
-    .iOS("13.0"),
-    .tvOS("13.0"),
-    .watchOS("6.0"),
-  ],
   products: [
     .library(name: "AsyncAlgorithms", targets: ["AsyncAlgorithms"])
   ],

Package@swift-5.7.swift

@@ -4,12 +4,6 @@ import PackageDescription
 
 let package = Package(
   name: "swift-async-algorithms",
-  platforms: [
-    .macOS("10.15"),
-    .iOS("13.0"),
-    .tvOS("13.0"),
-    .watchOS("6.0"),
-  ],
   products: [
     .library(name: "AsyncAlgorithms", targets: ["AsyncAlgorithms"]),
     .library(name: "AsyncSequenceValidation", targets: ["AsyncSequenceValidation"]),

Sources/AsyncAlgorithms/AsyncAdjacentPairsSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence {
   /// An `AsyncSequence` that iterates over the adjacent pairs of the original
   /// original `AsyncSequence`.
@@ -35,6 +36,7 @@ extension AsyncSequence {
 /// An `AsyncSequence` that iterates over the adjacent pairs of the original
 /// `AsyncSequence`.
 @frozen
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncAdjacentPairsSequence<Base: AsyncSequence>: AsyncSequence {
   public typealias Element = (Base.Element, Base.Element)
 
@@ -83,6 +85,7 @@ public struct AsyncAdjacentPairsSequence<Base: AsyncSequence>: AsyncSequence {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncAdjacentPairsSequence: Sendable where Base: Sendable, Base.Element: Sendable {}
 
 @available(*, unavailable)

Sources/AsyncAlgorithms/AsyncBufferedByteIterator.swift

@@ -39,6 +39,7 @@
 ///     }
 ///
 ///
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncBufferedByteIterator: AsyncIteratorProtocol {
   public typealias Element = UInt8
   @usableFromInline var buffer: _AsyncBytesBuffer
@@ -68,6 +69,7 @@ public struct AsyncBufferedByteIterator: AsyncIteratorProtocol {
 extension AsyncBufferedByteIterator: Sendable {}
 
 @frozen @usableFromInline
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 internal struct _AsyncBytesBuffer {
   @usableFromInline
   final class Storage {

Sources/AsyncAlgorithms/AsyncChain2Sequence.swift

@@ -18,6 +18,7 @@
 /// - Returns: An asynchronous sequence that iterates first over the elements of `s1`, and
 ///   then over the elements of `s2`.
 @inlinable
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public func chain<Base1: AsyncSequence, Base2: AsyncSequence>(
   _ s1: Base1,
   _ s2: Base2
@@ -27,6 +28,7 @@ public func chain<Base1: AsyncSequence, Base2: AsyncSequence>(
 
 /// A concatenation of two asynchronous sequences with the same element type.
 @frozen
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncChain2Sequence<Base1: AsyncSequence, Base2: AsyncSequence> where Base1.Element == Base2.Element {
   @usableFromInline
   let base1: Base1
@@ -41,6 +43,7 @@ public struct AsyncChain2Sequence<Base1: AsyncSequence, Base2: AsyncSequence> wh
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncChain2Sequence: AsyncSequence {
   public typealias Element = Base1.Element
 
@@ -82,6 +85,7 @@ extension AsyncChain2Sequence: AsyncSequence {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncChain2Sequence: Sendable where Base1: Sendable, Base2: Sendable {}
 
 @available(*, unavailable)

Sources/AsyncAlgorithms/AsyncChain3Sequence.swift

@@ -19,6 +19,7 @@
 /// - Returns: An asynchronous sequence that iterates first over the elements of `s1`, and
 ///   then over the elements of `s2`, and then over the elements of `s3`
 @inlinable
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public func chain<Base1: AsyncSequence, Base2: AsyncSequence, Base3: AsyncSequence>(
   _ s1: Base1,
   _ s2: Base2,
@@ -29,6 +30,7 @@ public func chain<Base1: AsyncSequence, Base2: AsyncSequence, Base3: AsyncSequen
 
 /// A concatenation of three asynchronous sequences with the same element type.
 @frozen
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncChain3Sequence<Base1: AsyncSequence, Base2: AsyncSequence, Base3: AsyncSequence>
 where Base1.Element == Base2.Element, Base1.Element == Base3.Element {
   @usableFromInline
@@ -48,6 +50,7 @@ where Base1.Element == Base2.Element, Base1.Element == Base3.Element {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncChain3Sequence: AsyncSequence {
   public typealias Element = Base1.Element
 
@@ -99,6 +102,7 @@ extension AsyncChain3Sequence: AsyncSequence {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncChain3Sequence: Sendable where Base1: Sendable, Base2: Sendable, Base3: Sendable {}
 
 @available(*, unavailable)

Sources/AsyncAlgorithms/AsyncChunkedByGroupSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence {
   /// Creates an asynchronous sequence that creates chunks of a given `RangeReplaceableCollection`
   /// type by testing if elements belong in the same group.
@@ -51,6 +52,7 @@ extension AsyncSequence {
 ///      // [10, 20, 30]
 ///      // [10, 40, 40]
 ///      // [10, 20]
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncChunkedByGroupSequence<Base: AsyncSequence, Collected: RangeReplaceableCollection>: AsyncSequence
 where Collected.Element == Base.Element {
   public typealias Element = Collected
@@ -121,6 +123,7 @@ where Collected.Element == Base.Element {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncChunkedByGroupSequence: Sendable where Base: Sendable, Base.Element: Sendable {}
 
 @available(*, unavailable)

Sources/AsyncAlgorithms/AsyncChunkedOnProjectionSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence {
   /// Creates an asynchronous sequence that creates chunks of a given `RangeReplaceableCollection` type on the uniqueness of a given subject.
   @inlinable
@@ -29,6 +30,7 @@ extension AsyncSequence {
 }
 
 /// An `AsyncSequence` that chunks on a subject when it differs from the last element.
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncChunkedOnProjectionSequence<
   Base: AsyncSequence,
   Subject: Equatable,
@@ -104,6 +106,7 @@ public struct AsyncChunkedOnProjectionSequence<
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncChunkedOnProjectionSequence: Sendable where Base: Sendable, Base.Element: Sendable {}
 
 @available(*, unavailable)

Sources/AsyncAlgorithms/AsyncChunksOfCountOrSignalSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence {
   /// Creates an asynchronous sequence that creates chunks of a given `RangeReplaceableCollection` type of a given count or when a signal `AsyncSequence` produces an element.
   public func chunks<Signal, Collected: RangeReplaceableCollection>(
@@ -78,6 +79,7 @@ extension AsyncSequence {
 }
 
 /// An `AsyncSequence` that chunks elements into collected `RangeReplaceableCollection` instances by either count or a signal from another `AsyncSequence`.
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncChunksOfCountOrSignalSequence<
   Base: AsyncSequence,
   Collected: RangeReplaceableCollection,

Sources/AsyncAlgorithms/AsyncChunksOfCountSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence {
   /// Creates an asynchronous sequence that creates chunks of a given `RangeReplaceableCollection` of a given count.
   @inlinable
@@ -27,6 +28,7 @@ extension AsyncSequence {
 }
 
 /// An `AsyncSequence` that chunks elements into `RangeReplaceableCollection` instances of at least a given count.
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncChunksOfCountSequence<Base: AsyncSequence, Collected: RangeReplaceableCollection>: AsyncSequence
 where Collected.Element == Base.Element {
   public typealias Element = Collected
@@ -89,8 +91,14 @@ where Collected.Element == Base.Element {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncChunksOfCountSequence: Sendable where Base: Sendable, Base.Element: Sendable {}
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncChunksOfCountSequence.Iterator: Sendable where Base.AsyncIterator: Sendable, Base.Element: Sendable {}
 
-@available(*, unavailable)
-extension AsyncChunksOfCountSequence.Iterator: Sendable {}
+// The following conflicts with the above conformance. The compiler is okay with this
+// when 'platforms' are specified in the package manifest but not when the @available
+// attribute is used instead.
+//
+// @available(*, unavailable)
+// extension AsyncChunksOfCountSequence.Iterator: Sendable { }

Sources/AsyncAlgorithms/AsyncCompactedSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence {
   /// Returns a new `AsyncSequence` that iterates over every non-nil element from the
   /// original `AsyncSequence`.
@@ -28,6 +29,7 @@ extension AsyncSequence {
 /// An `AsyncSequence` that iterates over every non-nil element from the original
 /// `AsyncSequence`.
 @frozen
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncCompactedSequence<Base: AsyncSequence, Element>: AsyncSequence
 where Base.Element == Element? {
 
@@ -66,6 +68,7 @@ where Base.Element == Element? {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncCompactedSequence: Sendable where Base: Sendable, Base.Element: Sendable {}
 
 @available(*, unavailable)

Sources/AsyncAlgorithms/AsyncExclusiveReductionsSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence {
   /// Returns an asynchronous sequence containing the accumulated results of combining the
   /// elements of the asynchronous sequence using the given closure.
@@ -57,6 +58,7 @@ extension AsyncSequence {
 /// An asynchronous sequence of applying a transform to the element of an asynchronous sequence and the
 /// previously transformed result.
 @frozen
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncExclusiveReductionsSequence<Base: AsyncSequence, Element> {
   @usableFromInline
   let base: Base
@@ -75,6 +77,7 @@ public struct AsyncExclusiveReductionsSequence<Base: AsyncSequence, Element> {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncExclusiveReductionsSequence: AsyncSequence {
   /// The iterator for an `AsyncExclusiveReductionsSequence` instance.
   @frozen
@@ -119,6 +122,7 @@ extension AsyncExclusiveReductionsSequence: AsyncSequence {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncExclusiveReductionsSequence: Sendable where Base: Sendable, Element: Sendable {}
 
 @available(*, unavailable)

Sources/AsyncAlgorithms/AsyncInclusiveReductionsSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence {
   /// Returns an asynchronous sequence containing the accumulated results of combining the
   /// elements of the asynchronous sequence using the given closure.
@@ -39,6 +40,7 @@ extension AsyncSequence {
 /// An asynchronous sequence containing the accumulated results of combining the
 /// elements of the asynchronous sequence using a given closure.
 @frozen
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncInclusiveReductionsSequence<Base: AsyncSequence> {
   @usableFromInline
   let base: Base
@@ -53,6 +55,7 @@ public struct AsyncInclusiveReductionsSequence<Base: AsyncSequence> {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncInclusiveReductionsSequence: AsyncSequence {
   public typealias Element = Base.Element
 
@@ -95,6 +98,7 @@ extension AsyncInclusiveReductionsSequence: AsyncSequence {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncInclusiveReductionsSequence: Sendable where Base: Sendable {}
 
 @available(*, unavailable)

Sources/AsyncAlgorithms/AsyncJoinedBySeparatorSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence where Element: AsyncSequence {
   /// Concatenate an `AsyncSequence` of `AsyncSequence` elements with a separator.
   @inlinable
@@ -20,6 +21,7 @@ extension AsyncSequence where Element: AsyncSequence {
 }
 
 /// An `AsyncSequence` that concatenates `AsyncSequence` elements with a separator.
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncJoinedBySeparatorSequence<Base: AsyncSequence, Separator: AsyncSequence>: AsyncSequence
 where Base.Element: AsyncSequence, Separator.Element == Base.Element.Element {
   public typealias Element = Base.Element.Element
@@ -143,6 +145,7 @@ where Base.Element: AsyncSequence, Separator.Element == Base.Element.Element {
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncJoinedBySeparatorSequence: Sendable
 where Base: Sendable, Base.Element: Sendable, Base.Element.Element: Sendable, Separator: Sendable {}
 

Sources/AsyncAlgorithms/AsyncJoinedSequence.swift

@@ -9,6 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncSequence where Element: AsyncSequence {
   /// Concatenate an `AsyncSequence` of `AsyncSequence` elements
   @inlinable
@@ -19,6 +20,7 @@ extension AsyncSequence where Element: AsyncSequence {
 
 /// An `AsyncSequence` that concatenates`AsyncSequence` elements
 @frozen
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 public struct AsyncJoinedSequence<Base: AsyncSequence>: AsyncSequence where Base.Element: AsyncSequence {
   public typealias Element = Base.Element.Element
   public typealias AsyncIterator = Iterator
@@ -90,6 +92,7 @@ public struct AsyncJoinedSequence<Base: AsyncSequence>: AsyncSequence where Base
   }
 }
 
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension AsyncJoinedSequence: Sendable
 where Base: Sendable, Base.Element: Sendable, Base.Element.Element: Sendable {}