remove usages of @warn_unused_result since it is now the default

Author: phausler

Foundation/CharacterSet.swift

@@ -402,13 +402,11 @@ public struct CharacterSet : ReferenceConvertible, Equatable, Hashable, SetAlgeb
     }
 
     /// Test for membership of a particular `UnicodeScalar` in the `CharacterSet`.
-    @warn_unused_result
     public func contains(_ member: UnicodeScalar) -> Bool {
         return _mapUnmanaged { $0.longCharacterIsMember(member.value) }
     }
 
     /// Returns a union of the `CharacterSet` with another `CharacterSet`.
-    @warn_unused_result
     public func union(_ other: CharacterSet) -> CharacterSet {
         // The underlying collection does not have a method to return new CharacterSets with changes applied, so we will copy and apply here
         var result = self
@@ -422,7 +420,6 @@ public struct CharacterSet : ReferenceConvertible, Equatable, Hashable, SetAlgeb
     }
 
     /// Returns an intersection of the `CharacterSet` with another `CharacterSet`.
-    @warn_unused_result
     public func intersection(_ other: CharacterSet) -> CharacterSet {
         // The underlying collection does not have a method to return new CharacterSets with changes applied, so we will copy and apply here
         var result = self
@@ -438,7 +435,6 @@ public struct CharacterSet : ReferenceConvertible, Equatable, Hashable, SetAlgeb
     }
 
     /// Returns the exclusive or of the `CharacterSet` with another `CharacterSet`.
-    @warn_unused_result
     public func symmetricDifference(_ other: CharacterSet) -> CharacterSet {
         return union(other).subtracting(intersection(other))
     }
@@ -449,7 +445,6 @@ public struct CharacterSet : ReferenceConvertible, Equatable, Hashable, SetAlgeb
     }
 
     /// Returns true if `self` is a superset of `other`.
-    @warn_unused_result
     public func isSuperset(of other: CharacterSet) -> Bool {
         return _mapUnmanaged { $0.isSuperset(of: other) }
     }
@@ -492,7 +487,6 @@ extension CharacterSet {
 }
 
 extension CharacterSet {
-    @warn_unused_result
     public func contains(_ member: unichar) -> Bool {
         return contains(UnicodeScalar(member))
     }

Foundation/Data.swift

@@ -369,7 +369,6 @@ public struct Data : ReferenceConvertible, CustomStringConvertible, Equatable, H
     /// - parameter buffer: A buffer to copy the data into.
     /// - parameter range: A range in the data to copy into the buffer. If the range is empty, this function will return 0 without copying anything. If the range is nil, as much data as will fit into `buffer` is copied.
     /// - returns: Number of bytes copied into the destination buffer.
-    @warn_unused_result
     public func copyBytes<DestinationType>(to buffer: UnsafeMutableBufferPointer<DestinationType>, from range: Range<Index>? = nil) -> Int {
         let cnt = count
         guard cnt > 0 else { return 0 }

Foundation/NSCoder.swift

@@ -46,7 +46,6 @@ public class NSCoder : NSObject {
         NSRequiresConcreteImplementation()
     }
 
-    @warn_unused_result
     public func decodeObjectOfClass<DecodedObjectType : NSCoding where DecodedObjectType : NSObject>(_ cls: DecodedObjectType.Type, forKey key: String) -> DecodedObjectType? {
         NSUnimplemented()
     }
@@ -62,22 +61,18 @@ public class NSCoder : NSObject {
         be casted to NSObject, nor is it Hashable.
      */
     /// - Experiment: This is a draft API currently under consideration for official import into Foundation
-    @warn_unused_result
     public func decodeObjectOfClasses(_ classes: [AnyClass], forKey key: String) -> AnyObject? {
         NSUnimplemented()
     }
 
-    @warn_unused_result
     public func decodeTopLevelObject() throws -> AnyObject? {
         NSUnimplemented()
     }
 
-    @warn_unused_result
     public func decodeTopLevelObjectForKey(_ key: String) throws -> AnyObject? {
         NSUnimplemented()
     }
 
-    @warn_unused_result
     public func decodeTopLevelObjectOfClass<DecodedObjectType : NSCoding where DecodedObjectType : NSObject>(_ cls: DecodedObjectType.Type, forKey key: String) throws -> DecodedObjectType? {
         NSUnimplemented()
     }
@@ -93,7 +88,6 @@ public class NSCoder : NSObject {
      be casted to NSObject, nor is it Hashable.
      */
     /// - Experiment: This is a draft API currently under consideration for official import into Foundation
-    @warn_unused_result
     public func decodeTopLevelObjectOfClasses(_ classes: [AnyClass], forKey key: String) throws -> AnyObject? {
         NSUnimplemented()
     }

Foundation/NSError.swift

@@ -192,7 +192,6 @@ public protocol __BridgedNSError : RawRepresentable, ErrorProtocol {
     static var __NSErrorDomain: String { get }
 }
 
-@warn_unused_result
 public func ==<T: __BridgedNSError where T.RawValue: SignedInteger>(lhs: T, rhs: T) -> Bool {
     return lhs.rawValue.toIntMax() == rhs.rawValue.toIntMax()
 }
@@ -216,7 +215,6 @@ public extension __BridgedNSError where RawValue: SignedInteger {
     public final var hashValue: Int { return _code }
 }
 
-@warn_unused_result
 public func ==<T: __BridgedNSError where T.RawValue: UnsignedInteger>(lhs: T, rhs: T) -> Bool {
     return lhs.rawValue.toUIntMax() == rhs.rawValue.toUIntMax()
 }

Foundation/NSKeyedUnarchiver.swift

@@ -651,27 +651,22 @@ public class NSKeyedUnarchiver : NSCoder {
         return nil
     }
 
-    @warn_unused_result
     public override func decodeObjectOfClass<DecodedObjectType : NSCoding where DecodedObjectType : NSObject>(_ cls: DecodedObjectType.Type, forKey key: String) -> DecodedObjectType? {
         return decodeObjectOfClasses([cls], forKey: key) as? DecodedObjectType
     }
 
-    @warn_unused_result
     public override func decodeObjectOfClasses(_ classes: [AnyClass], forKey key: String) -> AnyObject? {
         return _decodeObjectOfClasses(classes, forKey: key)
     }
 
-    @warn_unused_result
     public override func decodeTopLevelObjectForKey(_ key: String) throws -> AnyObject? {
         return try decodeTopLevelObjectOfClasses([NSArray.self], forKey: key)
     }
 
-    @warn_unused_result
     public override func decodeTopLevelObjectOfClass<DecodedObjectType : NSCoding where DecodedObjectType : NSObject>(_ cls: DecodedObjectType.Type, forKey key: String) throws -> DecodedObjectType? {
         return try self.decodeTopLevelObjectOfClasses([cls], forKey: key) as! DecodedObjectType?
     }
 
-    @warn_unused_result
     public override func decodeTopLevelObjectOfClasses(_ classes: [AnyClass], forKey key: String) throws -> AnyObject? {
         guard self._containers?.count == 1 else {
             throw _decodingError(NSCocoaError.CoderReadCorruptError,
@@ -895,7 +890,6 @@ public class NSKeyedUnarchiver : NSCoder {
 }
 
 extension NSKeyedUnarchiver {
-    @warn_unused_result
     public class func unarchiveTopLevelObjectWithData(_ data: Data) throws -> AnyObject? {
         var root : AnyObject? = nil
 

Foundation/NSRange.swift

@@ -43,7 +43,6 @@ extension NSRange {
         length = x.count
     }
 
-    @warn_unused_result
     public func toRange() -> CountableRange<Int>? {
         if location == NSNotFound { return nil }
         let min = location

Foundation/NSSwiftRuntime.swift

@@ -214,7 +214,6 @@ public protocol _ObjectTypeBridgeable {
     associatedtype _ObjectType : AnyObject
 
     /// Convert `self` to an Object type
-    @warn_unused_result
     func _bridgeToObject() -> _ObjectType
 
     /// Bridge from an object of the bridged class type to a value of