Add Optional/Result: Equatable where Element: ~Copyable

Author: airspeedswift

stdlib/public/core/Optional.swift

@@ -522,7 +522,8 @@ func _diagnoseUnexpectedNilOptional(
   }
 }
 
-extension Optional: Equatable where Wrapped: Equatable {
+@_preInverseGenerics
+extension Optional: Equatable where Wrapped: Equatable & ~Copyable {
   /// Returns a Boolean value indicating whether two optional instances are
   /// equal.
   ///
@@ -568,14 +569,19 @@ extension Optional: Equatable where Wrapped: Equatable {
   ///   - lhs: An optional value to compare.
   ///   - rhs: Another optional value to compare.
   @_transparent
-  public static func ==(lhs: Wrapped?, rhs: Wrapped?) -> Bool {
-    switch (lhs, rhs) {
-    case let (l?, r?):
-      return l == r
-    case (nil, nil):
-      return true
-    default:
-      return false
+  @_preInverseGenerics
+  public static func ==(lhs: borrowing Wrapped?, rhs: borrowing Wrapped?) -> Bool {
+    switch lhs {
+    case let l?:
+      switch rhs {
+      case let r?: l == r
+      case nil: false
+      }
+    case nil:
+      switch rhs {
+      case _?: false
+      case nil: true
+      }
     }
   }
 }

stdlib/public/core/Result.swift

@@ -27,7 +27,24 @@ extension Result: Escapable where Success: Escapable & ~Copyable {}
 
 extension Result: Sendable where Success: Sendable & ~Copyable & ~Escapable {}
 
-extension Result: Equatable where Success: Equatable, Failure: Equatable {}
+@_preInverseGenerics
+extension Result: Equatable where Success: Equatable & ~Copyable, Failure: Equatable {
+  @_preInverseGenerics
+  public static func ==(lhs: borrowing Self, rhs: borrowing Self) -> Bool {
+    switch lhs {
+      case let .success(l):
+      switch rhs {
+        case let .success(r): l == r
+        case .failure: false
+      }
+      case let .failure(l):
+      switch rhs {
+        case .success: false
+        case let .failure(r): l == r
+      }
+    }
+  }
+}
 
 extension Result: Hashable where Success: Hashable, Failure: Hashable {}
 

test/api-digester/Outputs/stability-stdlib-source-base.swift.expected

@@ -270,10 +270,14 @@ Func Optional.!=(_:_:) has generic signature change from <Wrapped> to <Wrapped w
 Func Optional.!=(_:_:) has parameter 0 changing from Default to Shared
 Func Optional.!=(_:_:) has parameter 1 changing from Default to Shared
 Func Optional.==(_:_:) has generic signature change from <Wrapped> to <Wrapped where Wrapped : ~Copyable, Wrapped : ~Escapable>
+Func Optional.==(_:_:) has generic signature change from <Wrapped where Wrapped : Swift.Equatable> to <Wrapped where Wrapped : Swift.Equatable, Wrapped : ~Copyable>
 Func Optional.==(_:_:) has parameter 0 changing from Default to Shared
 Func Optional.==(_:_:) has parameter 1 changing from Default to Shared
 Func Optional.~=(_:_:) has generic signature change from <Wrapped> to <Wrapped where Wrapped : ~Copyable, Wrapped : ~Escapable>
 Func Optional.~=(_:_:) has parameter 1 changing from Default to Shared
+Func Result.==(_:_:) has generic signature change from <Success, Failure where Success : Swift.Equatable, Failure : Swift.Equatable, Failure : Swift.Error> to <Success, Failure where Success : Swift.Equatable, Failure : Swift.Equatable, Failure : Swift.Error, Success : ~Copyable>
+Func Result.==(_:_:) has parameter 0 changing from Default to Shared
+Func Result.==(_:_:) has parameter 1 changing from Default to Shared
 Func Result.get() has generic signature change from <Success, Failure where Failure : Swift.Error> to <Success, Failure where Failure : Swift.Error, Success : ~Copyable, Success : ~Escapable>
 Func Result.get() has self access kind changing from NonMutating to Consuming
 Func Result.mapError(_:) has self access kind changing from NonMutating to Consuming

test/api-digester/stability-stdlib-abi-without-asserts.test

@@ -611,7 +611,9 @@ Func Optional.!=(_:_:) has mangled name changing from 'static Swift.Optional.!=
 Func Optional.!=(_:_:) has parameter 0 changing from Default to Shared
 Func Optional.!=(_:_:) has parameter 1 changing from Default to Shared
 Func Optional.!=(_:_:) is now with @_preInverseGenerics
+Func Optional.==(_:_:) has generic signature change from <Wrapped where Wrapped : Swift.Equatable> to <Wrapped where Wrapped : Swift.Equatable, Wrapped : ~Copyable>
 Func Optional.==(_:_:) has generic signature change from <Wrapped> to <Wrapped where Wrapped : ~Copyable, Wrapped : ~Escapable>
+Func Optional.==(_:_:) has mangled name changing from 'static (extension in Swift):Swift.Optional<A where A: Swift.Equatable>.== infix(Swift.Optional<A>, Swift.Optional<A>) -> Swift.Bool' to 'static (extension in Swift):Swift.Optional< where A: Swift.Equatable, A: ~Swift.Copyable>.== infix(Swift.Optional<A>, Swift.Optional<A>) -> Swift.Bool'
 Func Optional.==(_:_:) has mangled name changing from 'static Swift.Optional.== infix(Swift.Optional<A>, Swift._OptionalNilComparisonType) -> Swift.Bool' to 'static (extension in Swift):Swift.Optional< where A: ~Swift.Copyable, A: ~Swift.Escapable>.== infix(Swift.Optional<A>, Swift._OptionalNilComparisonType) -> Swift.Bool'
 Func Optional.==(_:_:) has mangled name changing from 'static Swift.Optional.== infix(Swift._OptionalNilComparisonType, Swift.Optional<A>) -> Swift.Bool' to 'static (extension in Swift):Swift.Optional< where A: ~Swift.Copyable, A: ~Swift.Escapable>.== infix(Swift._OptionalNilComparisonType, Swift.Optional<A>) -> Swift.Bool'
 Func Optional.==(_:_:) has parameter 0 changing from Default to Shared
@@ -623,6 +625,11 @@ Func Optional.~=(_:_:) has parameter 1 changing from Default to Shared
 Func Optional.~=(_:_:) is now with @_preInverseGenerics
 Func Result.get() has been removed
 Func Result.mapError(_:) has been removed
+Func Result.==(_:_:) has generic signature change from <Success, Failure where Success : Swift.Equatable, Failure : Swift.Equatable, Failure : Swift.Error> to <Success, Failure where Success : Swift.Equatable, Failure : Swift.Equatable, Failure : Swift.Error, Success : ~Copyable>
+Func Result.==(_:_:) has mangled name changing from 'static (extension in Swift):Swift.Result< where A: Swift.Equatable, B: Swift.Equatable>.== infix(Swift.Result<A, B>, Swift.Result<A, B>) -> Swift.Bool' to 'static (extension in Swift):Swift.Result< where A: Swift.Equatable, B: Swift.Equatable, A: ~Swift.Copyable>.== infix(Swift.Result<A, B>, Swift.Result<A, B>) -> Swift.Bool'
+Func Result.==(_:_:) has parameter 0 changing from Default to Shared
+Func Result.==(_:_:) has parameter 1 changing from Default to Shared
+Func Result.==(_:_:) is now with @_preInverseGenerics
 Func TextOutputStreamable.write(to:) has generic signature change from <Self, Target where Self : Swift.TextOutputStreamable, Target : Swift.TextOutputStream> to <Self, Target where Self : Swift.TextOutputStreamable, Target : Swift.TextOutputStream, Self : ~Copyable>
 Func UnsafeBufferPointer.deallocate() has generic signature change from <Element> to <Element where Element : ~Copyable>
 Func UnsafeBufferPointer.deallocate() has mangled name changing from 'Swift.UnsafeBufferPointer.deallocate() -> ()' to '(extension in Swift):Swift.UnsafeBufferPointer< where A: ~Swift.Copyable>.deallocate() -> ()'

test/stdlib/NoncopyableEquatable.swift

@@ -71,7 +71,7 @@ NoncopyableEquatableTests.test("comparing noncopyables") {
     expectTrue(array.minIndex() == 2)
  }
 
- extension Noncopyable: CustomStringConvertible {
+extension Noncopyable: CustomStringConvertible {
     var description: String {
         "No copying the number \(i)"
     }
@@ -100,12 +100,48 @@ func debug(value: borrowing some CustomDebugStringConvertible & ~Copyable) -> St
     value.debugDescription
 }
 
- NoncopyableEquatableTests.test("noncopyable interpolation") {
+NoncopyableEquatableTests.test("noncopyable interpolation") {
 
     let a = Noncopyable(riskily: "99")
 
     expectEqual("NC: \(a)", "NC: No copying the number \(a.i)")
     expectEqual("Noncopyable(i: \(a.i))", debug(value: a))
- }
+}
+
+NoncopyableEquatableTests.test("equating optional noncopyables") {
+    let o1: Noncopyable? = Noncopyable(i: 1)
+    let o2: Noncopyable = .init(i: 1)
+    expectTrue(o1 == consume o2)
+}
+
+
+extension Noncopyable {
+    struct Nope: Error, Equatable { let s: String }
+
+    init(throws from: String) throws(Nope) {
+        guard let i = Int(from) else { throw Nope(s: from) }
+        self = .init(i: i)
+    }
+}
+
+NoncopyableEquatableTests.test("equating optional noncopyables") {
+    let o1: Noncopyable? = Noncopyable(i: 1)
+    let o2: Noncopyable = .init(i: 1)
+    expectTrue(o1 == consume o2)
+}
+
+NoncopyableEquatableTests.test("noncopyable result") {
+    let r = Result { () throws(Noncopyable.Nope) -> Noncopyable in 
+        try Noncopyable(throws: "99") 
+    }
+    expectTrue(r == .success(.init(i: 99)))
+
+    let n = Result { () throws(Noncopyable.Nope) -> Noncopyable in try Noncopyable(throws: "nope") }
+    expectTrue(r != n)
+    let m = Result { () throws(Noncopyable.Nope) -> Noncopyable in  try Noncopyable(throws: "nope") }
+    expectTrue(n == m)
+
+    expectEqual(try! r.get().i, 99)
+}
 
 runAllTests()