Make ValueTuple types serializable (#9271)

src/mscorlib/src/System/ValueTuple.cs

@@ -28,6 +28,7 @@ internal interface IValueTupleInternal : ITuple
     /// - they are mutable rather than readonly, and
     /// - their members (such as Item1, Item2, etc) are fields rather than properties.
     /// </summary>
+    [Serializable]
     public struct ValueTuple
         : IEquatable<ValueTuple>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple>, IValueTupleInternal, ITuple
     {
@@ -296,6 +297,7 @@ internal static int CombineHashCodes(int h1, int h2, int h3, int h4, int h5, int
 
     /// <summary>Represents a 1-tuple, or singleton, as a value type.</summary>
     /// <typeparam name="T1">The type of the tuple's only component.</typeparam>
+    [Serializable]
     public struct ValueTuple<T1>
         : IEquatable<ValueTuple<T1>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1>>, IValueTupleInternal, ITuple
     {
@@ -460,6 +462,7 @@ string IValueTupleInternal.ToStringEnd()
     /// </summary>
     /// <typeparam name="T1">The type of the tuple's first component.</typeparam>
     /// <typeparam name="T2">The type of the tuple's second component.</typeparam>
+    [Serializable]
     [StructLayout(LayoutKind.Auto)]
     public struct ValueTuple<T1, T2>
         : IEquatable<ValueTuple<T1, T2>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2>>, IValueTupleInternal, ITuple
@@ -669,6 +672,7 @@ string IValueTupleInternal.ToStringEnd()
     /// <typeparam name="T1">The type of the tuple's first component.</typeparam>
     /// <typeparam name="T2">The type of the tuple's second component.</typeparam>
     /// <typeparam name="T3">The type of the tuple's third component.</typeparam>
+    [Serializable]
     [StructLayout(LayoutKind.Auto)]
     public struct ValueTuple<T1, T2, T3>
         : IEquatable<ValueTuple<T1, T2, T3>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2, T3>>, IValueTupleInternal, ITuple
@@ -876,6 +880,7 @@ string IValueTupleInternal.ToStringEnd()
     /// <typeparam name="T2">The type of the tuple's second component.</typeparam>
     /// <typeparam name="T3">The type of the tuple's third component.</typeparam>
     /// <typeparam name="T4">The type of the tuple's fourth component.</typeparam>
+    [Serializable]
     [StructLayout(LayoutKind.Auto)]
     public struct ValueTuple<T1, T2, T3, T4>
         : IEquatable<ValueTuple<T1, T2, T3, T4>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2, T3, T4>>, IValueTupleInternal, ITuple
@@ -1102,6 +1107,7 @@ string IValueTupleInternal.ToStringEnd()
     /// <typeparam name="T3">The type of the tuple's third component.</typeparam>
     /// <typeparam name="T4">The type of the tuple's fourth component.</typeparam>
     /// <typeparam name="T5">The type of the tuple's fifth component.</typeparam>
+    [Serializable]
     [StructLayout(LayoutKind.Auto)]
     public struct ValueTuple<T1, T2, T3, T4, T5>
         : IEquatable<ValueTuple<T1, T2, T3, T4, T5>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2, T3, T4, T5>>, IValueTupleInternal, ITuple
@@ -1347,6 +1353,7 @@ string IValueTupleInternal.ToStringEnd()
     /// <typeparam name="T4">The type of the tuple's fourth component.</typeparam>
     /// <typeparam name="T5">The type of the tuple's fifth component.</typeparam>
     /// <typeparam name="T6">The type of the tuple's sixth component.</typeparam>
+    [Serializable]
     [StructLayout(LayoutKind.Auto)]
     public struct ValueTuple<T1, T2, T3, T4, T5, T6>
         : IEquatable<ValueTuple<T1, T2, T3, T4, T5, T6>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2, T3, T4, T5, T6>>, IValueTupleInternal, ITuple
@@ -1611,6 +1618,7 @@ string IValueTupleInternal.ToStringEnd()
     /// <typeparam name="T5">The type of the tuple's fifth component.</typeparam>
     /// <typeparam name="T6">The type of the tuple's sixth component.</typeparam>
     /// <typeparam name="T7">The type of the tuple's seventh component.</typeparam>
+    [Serializable]
     [StructLayout(LayoutKind.Auto)]
     public struct ValueTuple<T1, T2, T3, T4, T5, T6, T7>
         : IEquatable<ValueTuple<T1, T2, T3, T4, T5, T6, T7>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2, T3, T4, T5, T6, T7>>, IValueTupleInternal, ITuple
@@ -1894,6 +1902,7 @@ string IValueTupleInternal.ToStringEnd()
     /// <typeparam name="T6">The type of the tuple's sixth component.</typeparam>
     /// <typeparam name="T7">The type of the tuple's seventh component.</typeparam>
     /// <typeparam name="TRest">The type of the tuple's eighth component.</typeparam>
+    [Serializable]
     [StructLayout(LayoutKind.Auto)]
     public struct ValueTuple<T1, T2, T3, T4, T5, T6, T7, TRest>
     : IEquatable<ValueTuple<T1, T2, T3, T4, T5, T6, T7, TRest>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2, T3, T4, T5, T6, T7, TRest>>, IValueTupleInternal, ITuple