[BitwiseCopyable] Don't apply to FixedWidthInteger.

Per LWG feedback.

This reverts commit c8119e3.

Author: nate-chandler

stdlib/public/core/Integers.swift

@@ -1902,8 +1902,7 @@ public protocol _LosslessStringConvertibleOrNone {}
 /// customization points for arithmetic operations. When you provide just those
 /// methods, the standard library provides default implementations for all
 /// other arithmetic methods and operators.
-public protocol FixedWidthInteger
-: BinaryInteger, _LosslessStringConvertibleOrNone, _BitwiseCopyable
+public protocol FixedWidthInteger: BinaryInteger, _LosslessStringConvertibleOrNone
 where Magnitude: FixedWidthInteger & UnsignedInteger,
       Stride: FixedWidthInteger & SignedInteger {
   /// The number of bits used for the underlying binary representation of

test/api-digester/Outputs/cake-abi.json

@@ -1745,13 +1745,6 @@
             "usr": "s:s25LosslessStringConvertibleP",
             "mangledName": "$ss25LosslessStringConvertibleP"
           },
-          {
-            "kind": "Conformance",
-            "name": "_BitwiseCopyable",
-            "printedName": "_BitwiseCopyable",
-            "usr": "s:s16_BitwiseCopyableP",
-            "mangledName": "$ss16_BitwiseCopyableP"
-          },
           {
             "kind": "Conformance",
             "name": "SignedNumeric",
@@ -2029,6 +2022,13 @@
             ],
             "usr": "s:s10SIMDScalarP",
             "mangledName": "$ss10SIMDScalarP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "_BitwiseCopyable",
+            "printedName": "_BitwiseCopyable",
+            "usr": "s:s16_BitwiseCopyableP",
+            "mangledName": "$ss16_BitwiseCopyableP"
           }
         ]
       }

test/api-digester/Outputs/stability-stdlib-source-x86_64.swift.expected

@@ -48,4 +48,3 @@ Func withoutActuallyEscaping(_:do:) is now without @rethrows
 
 Protocol SIMDScalar has generic signature change from <Self == Self.SIMD16Storage.Scalar, Self.SIMD16Storage : Swift.SIMDStorage, Self.SIMD2Storage : Swift.SIMDStorage, Self.SIMD32Storage : Swift.SIMDStorage, Self.SIMD4Storage : Swift.SIMDStorage, Self.SIMD64Storage : Swift.SIMDStorage, Self.SIMD8Storage : Swift.SIMDStorage, Self.SIMDMaskScalar : Swift.FixedWidthInteger, Self.SIMDMaskScalar : Swift.SIMDScalar, Self.SIMDMaskScalar : Swift.SignedInteger, Self.SIMD16Storage.Scalar == Self.SIMD2Storage.Scalar, Self.SIMD2Storage.Scalar == Self.SIMD32Storage.Scalar, Self.SIMD32Storage.Scalar == Self.SIMD4Storage.Scalar, Self.SIMD4Storage.Scalar == Self.SIMD64Storage.Scalar, Self.SIMD64Storage.Scalar == Self.SIMD8Storage.Scalar> to <Self : Swift._BitwiseCopyable, Self == Self.SIMD16Storage.Scalar, Self.SIMD16Storage : Swift.SIMDStorage, Self.SIMD2Storage : Swift.SIMDStorage, Self.SIMD32Storage : Swift.SIMDStorage, Self.SIMD4Storage : Swift.SIMDStorage, Self.SIMD64Storage : Swift.SIMDStorage, Self.SIMD8Storage : Swift.SIMDStorage, Self.SIMDMaskScalar : Swift.FixedWidthInteger, Self.SIMDMaskScalar : Swift.SIMDScalar, Self.SIMDMaskScalar : Swift.SignedInteger, Self.SIMDMaskScalar == Self.SIMDMaskScalar.SIMDMaskScalar, Self.SIMD16Storage.Scalar == Self.SIMD2Storage.Scalar, Self.SIMD2Storage.Scalar == Self.SIMD32Storage.Scalar, Self.SIMD32Storage.Scalar == Self.SIMD4Storage.Scalar, Self.SIMD4Storage.Scalar == Self.SIMD64Storage.Scalar, Self.SIMD64Storage.Scalar == Self.SIMD8Storage.Scalar>
 Protocol SIMDStorage has generic signature change from <Self.Scalar : Swift.Decodable, Self.Scalar : Swift.Encodable, Self.Scalar : Swift.Hashable> to <Self : Swift._BitwiseCopyable, Self.Scalar : Swift.Decodable, Self.Scalar : Swift.Encodable, Self.Scalar : Swift.Hashable>
-Protocol FixedWidthInteger has generic signature change from <Self : Swift.BinaryInteger, Self : Swift.LosslessStringConvertible, Self.Magnitude : Swift.FixedWidthInteger, Self.Magnitude : Swift.UnsignedInteger, Self.Stride : Swift.FixedWidthInteger, Self.Stride : Swift.SignedInteger> to <Self : Swift.BinaryInteger, Self : Swift.LosslessStringConvertible, Self : Swift._BitwiseCopyable, Self.Magnitude : Swift.FixedWidthInteger, Self.Magnitude : Swift.UnsignedInteger, Self.Stride : Swift.FixedWidthInteger, Self.Stride : Swift.SignedInteger>

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

@@ -191,8 +191,5 @@ Protocol SIMDStorage has added inherited protocol _BitwiseCopyable
 Protocol SIMDStorage has generic signature change from <Self.Scalar : Swift.Decodable, Self.Scalar : Swift.Encodable, Self.Scalar : Swift.Hashable> to <Self : Swift._BitwiseCopyable, Self.Scalar : Swift.Decodable, Self.Scalar : Swift.Encodable, Self.Scalar : Swift.Hashable>
 Protocol _Pointer has added inherited protocol _BitwiseCopyable
 Protocol _Pointer has generic signature change from <Self : Swift.CustomDebugStringConvertible, Self : Swift.CustomReflectable, Self : Swift.Hashable, Self : Swift.Strideable> to <Self : Swift.CustomDebugStringConvertible, Self : Swift.CustomReflectable, Self : Swift.Hashable, Self : Swift.Strideable, Self : Swift._BitwiseCopyable>
-Protocol FixedWidthInteger has added inherited protocol _BitwiseCopyable
-Protocol FixedWidthInteger has generic signature change from <Self : Swift.BinaryInteger, Self : Swift.LosslessStringConvertible, Self.Magnitude : Swift.FixedWidthInteger, Self.Magnitude : Swift.UnsignedInteger, Self.Stride : Swift.FixedWidthInteger, Self.Stride : Swift.SignedInteger> to <Self : Swift.BinaryInteger, Self : Swift.LosslessStringConvertible, Self : Swift._BitwiseCopyable, Self.Magnitude : Swift.FixedWidthInteger, Self.Magnitude : Swift.UnsignedInteger, Self.Stride : Swift.FixedWidthInteger, Self.Stride : Swift.SignedInteger>
-
 
 // *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment above.)