SR-5803: NSNumber no longer equates 1 and true (#1201)

* SR-5803: NSNumber no longer equates 1 and true

- Fix isEqual to work with NSNumbers initialised with different types
  (eg, float and UInt).

- Match the behaviour of Darwin where true can only equal an NSNumber
  with a value of exactly 1.

Author: spevans

Foundation/NSNumber.swift

@@ -226,7 +226,7 @@ open class NSNumber : NSValue {
         case let other as Bool:
             return boolValue == other
         case let other as NSNumber:
-            return CFEqual(_cfObject, other._cfObject)
+            return compare(other) == .orderedSame
         default:
             return false
         }

TestFoundation/TestNSNumber.swift

@@ -44,6 +44,7 @@ class TestNSNumber : XCTestCase {
             ("test_descriptionWithLocale", test_descriptionWithLocale ),
             ("test_objCType", test_objCType ),
             ("test_stringValue", test_stringValue),
+            ("test_Equals", test_Equals),
         ]
     }
 
@@ -1087,4 +1088,50 @@ class TestNSNumber : XCTestCase {
         XCTAssertEqual(NSNumber(value: Int64.max).stringValue, "9223372036854775807")
         XCTAssertEqual(NSNumber(value: Int64.max - 1).stringValue, "9223372036854775806")
     }
+
+    func test_Equals() {
+        // Booleans: false only equals 0, true only equals 1
+        XCTAssertTrue(NSNumber(value: true) == NSNumber(value: true))
+        XCTAssertTrue(NSNumber(value: true) == NSNumber(value: 1))
+        XCTAssertTrue(NSNumber(value: true) == NSNumber(value: Float(1)))
+        XCTAssertTrue(NSNumber(value: true) == NSNumber(value: Double(1)))
+        XCTAssertTrue(NSNumber(value: true) == NSNumber(value: Int8(1)))
+        XCTAssertTrue(NSNumber(value: true) != NSNumber(value: false))
+        XCTAssertTrue(NSNumber(value: true) != NSNumber(value: Int8(-1)))
+        XCTAssertTrue(NSNumber(value: true) != NSNumber(value: Float(1.01)))
+        XCTAssertTrue(NSNumber(value: true) != NSNumber(value: Double(1234.56)))
+        XCTAssertTrue(NSNumber(value: true) != NSNumber(value: 2))
+        XCTAssertTrue(NSNumber(value: true) != NSNumber(value: Int.max))
+        XCTAssertTrue(NSNumber(value: false) == NSNumber(value: false))
+        XCTAssertTrue(NSNumber(value: false) == NSNumber(value: 0))
+        XCTAssertTrue(NSNumber(value: false) == NSNumber(value: Float(0)))
+        XCTAssertTrue(NSNumber(value: false) == NSNumber(value: Double(0)))
+        XCTAssertTrue(NSNumber(value: false) == NSNumber(value: Int8(0)))
+        XCTAssertTrue(NSNumber(value: false) == NSNumber(value: UInt64(0)))
+        XCTAssertTrue(NSNumber(value: false) != NSNumber(value: 1))
+        XCTAssertTrue(NSNumber(value: false) != NSNumber(value: 2))
+        XCTAssertTrue(NSNumber(value: false) != NSNumber(value: Int.max))
+
+        XCTAssertTrue(NSNumber(value: Int8(-1)) == NSNumber(value: Int16(-1)))
+        XCTAssertTrue(NSNumber(value: Int16(-1)) == NSNumber(value: Int32(-1)))
+        XCTAssertTrue(NSNumber(value: Int32(-1)) == NSNumber(value: Int64(-1)))
+        XCTAssertTrue(NSNumber(value: Int8.max) != NSNumber(value: Int16.max))
+        XCTAssertTrue(NSNumber(value: Int16.max) != NSNumber(value: Int32.max))
+        XCTAssertTrue(NSNumber(value: Int32.max) != NSNumber(value: Int64.max))
+        XCTAssertTrue(NSNumber(value: UInt8.min) == NSNumber(value: UInt16.min))
+        XCTAssertTrue(NSNumber(value: UInt16.min) == NSNumber(value: UInt32.min))
+        XCTAssertTrue(NSNumber(value: UInt32.min) == NSNumber(value: UInt64.min))
+        XCTAssertTrue(NSNumber(value: UInt8.max) != NSNumber(value: UInt16.max))
+        XCTAssertTrue(NSNumber(value: UInt16.max) != NSNumber(value: UInt32.max))
+        XCTAssertTrue(NSNumber(value: UInt32.max) != NSNumber(value: UInt64.max))
+        XCTAssertTrue(NSNumber(value: Int8(0)) == NSNumber(value: UInt16(0)))
+        XCTAssertTrue(NSNumber(value: UInt16(0)) == NSNumber(value: Int32(0)))
+        XCTAssertTrue(NSNumber(value: Int32(0)) == NSNumber(value: UInt64(0)))
+        XCTAssertTrue(NSNumber(value: Int(0)) == NSNumber(value: UInt(0)))
+        XCTAssertTrue(NSNumber(value: Int8.min) == NSNumber(value: Float(-128)))
+        XCTAssertTrue(NSNumber(value: Int8.max) == NSNumber(value: Double(127)))
+        XCTAssertTrue(NSNumber(value: UInt16.min) == NSNumber(value: Float(0)))
+        XCTAssertTrue(NSNumber(value: UInt16.max) == NSNumber(value: Double(65535)))
+        XCTAssertTrue(NSNumber(value: 1.1) != NSNumber(value: Int64(1)))
+    }
 }