TypeForwardedFrom attributes on coretypes for NetFX serialization (#12059)

* TypeForwardedFrom attributes on coretypes for NetFX serialization

* ValueTuple added

* Removed StubEnvironment typeforwards

* Modified FQAN for some special type forwards

* Support desktop to core serialization with InternalsVisibleTo for mscorlib

* Remove typeforwards from nested types

* Removed unused file

50 files changed, 83 insertions, 86 deletions

diff --git a/src/mscorlib/System.Private.CoreLib.csproj b/src/mscorlib/System.Private.CoreLib.csproj
index 4d3be41d0a..5ae9c69360 100644
--- a/src/mscorlib/System.Private.CoreLib.csproj
+++ b/src/mscorlib/System.Private.CoreLib.csproj
@@ -617,7 +617,6 @@
     <Compile Include="$(BclSourcesRoot)\System\Resources\__HResults.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Resources\FileBasedResourceGroveler.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Resources\IResourceGroveler.cs" />
-    <Compile Include="$(BclSourcesRoot)\System\Resources\LooselyLinkedResourceReference.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Resources\ManifestBasedResourceGroveler.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Resources\ResourceManager.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Resources\ResourceReader.cs" />
diff --git a/src/mscorlib/shared/System/Char.cs b/src/mscorlib/shared/System/Char.cs
index 3fad7a4827..72441763e9 100644
--- a/src/mscorlib/shared/System/Char.cs
+++ b/src/mscorlib/shared/System/Char.cs
@@ -21,6 +21,7 @@ namespace System
 {
     [Serializable]
     [StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public struct Char : IComparable, IComparable<Char>, IEquatable<Char>, IConvertible
     {
         //
diff --git a/src/mscorlib/shared/System/Collections/DictionaryEntry.cs b/src/mscorlib/shared/System/Collections/DictionaryEntry.cs
index 290306d006..0815c93319 100644
--- a/src/mscorlib/shared/System/Collections/DictionaryEntry.cs
+++ b/src/mscorlib/shared/System/Collections/DictionaryEntry.cs
@@ -9,6 +9,7 @@ namespace System.Collections
     // A DictionaryEntry holds a key and a value from a dictionary.
     // It is returned by IDictionaryEnumerator::GetEntry().
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct DictionaryEntry
     {
         private Object _key;
diff --git a/src/mscorlib/shared/System/Collections/Generic/KeyValuePair.cs b/src/mscorlib/shared/System/Collections/Generic/KeyValuePair.cs
index fc51af25f8..6280218063 100644
--- a/src/mscorlib/shared/System/Collections/Generic/KeyValuePair.cs
+++ b/src/mscorlib/shared/System/Collections/Generic/KeyValuePair.cs
@@ -46,6 +46,7 @@ namespace System.Collections.Generic
     // It is used by the IEnumerable<T> implementation for both IDictionary<TKey, TValue>
     // and IReadOnlyDictionary<TKey, TValue>.
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct KeyValuePair<TKey, TValue>
     {
         private TKey key;       // DO NOT change the field name, it's required for compatibility with desktop .NET as it appears in serialization payload.
diff --git a/src/mscorlib/shared/System/DateTime.cs b/src/mscorlib/shared/System/DateTime.cs
index ddb72da77d..02f07d2865 100644
--- a/src/mscorlib/shared/System/DateTime.cs
+++ b/src/mscorlib/shared/System/DateTime.cs
@@ -54,6 +54,7 @@ namespace System
     // 
     [StructLayout(LayoutKind.Auto)]
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public partial struct DateTime : IComparable, IFormattable, IConvertible, IComparable<DateTime>, IEquatable<DateTime>, ISerializable
     {
         // Number of 100ns ticks per time unit
diff --git a/src/mscorlib/shared/System/DateTimeOffset.cs b/src/mscorlib/shared/System/DateTimeOffset.cs
index d5ccbd9195..6df35fed1e 100644
--- a/src/mscorlib/shared/System/DateTimeOffset.cs
+++ b/src/mscorlib/shared/System/DateTimeOffset.cs
@@ -30,6 +30,7 @@ namespace System
 
     [StructLayout(LayoutKind.Auto)]
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public struct DateTimeOffset : IComparable, IFormattable, IComparable<DateTimeOffset>, IEquatable<DateTimeOffset>, ISerializable, IDeserializationCallback
     {
         // Constants
diff --git a/src/mscorlib/shared/System/Globalization/SortVersion.cs b/src/mscorlib/shared/System/Globalization/SortVersion.cs
index 94c04d7063..46e9a833ec 100644
--- a/src/mscorlib/shared/System/Globalization/SortVersion.cs
+++ b/src/mscorlib/shared/System/Globalization/SortVersion.cs
@@ -5,6 +5,7 @@
 namespace System.Globalization
 {
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public sealed class SortVersion : IEquatable<SortVersion>
     {
         private int m_NlsVersion; // Do not rename (binary serialization)
diff --git a/src/mscorlib/shared/System/StringComparer.cs b/src/mscorlib/shared/System/StringComparer.cs
index b327e770d5..765f43ea1a 100644
--- a/src/mscorlib/shared/System/StringComparer.cs
+++ b/src/mscorlib/shared/System/StringComparer.cs
@@ -10,6 +10,7 @@ using System.Diagnostics.Contracts;
 namespace System
 {
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public abstract class StringComparer : IComparer, IEqualityComparer, IComparer<string>, IEqualityComparer<string>
     {
         private static readonly CultureAwareComparer s_invariantCulture = new CultureAwareComparer(CultureInfo.InvariantCulture, false);
@@ -170,6 +171,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     internal sealed class CultureAwareComparer : StringComparer
     {
         private readonly CompareInfo _compareInfo;
@@ -223,6 +225,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     internal sealed class OrdinalComparer : StringComparer 
     {
         public override int Compare(string x, string y) => string.CompareOrdinal(x, y);
@@ -248,6 +251,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     internal sealed class OrdinalIgnoreCaseComparer : StringComparer
     {
         public override int Compare(string x, string y) => string.Compare(x, y, StringComparison.OrdinalIgnoreCase);
diff --git a/src/mscorlib/shared/System/Text/StringBuilder.cs b/src/mscorlib/shared/System/Text/StringBuilder.cs
index 3a06114bff..29f0cdb18b 100644
--- a/src/mscorlib/shared/System/Text/StringBuilder.cs
+++ b/src/mscorlib/shared/System/Text/StringBuilder.cs
@@ -35,6 +35,7 @@ namespace System.Text
     // Console.WriteLine(sb2);
     // 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public sealed partial class StringBuilder : ISerializable
     {
         // A StringBuilder is internally represented as a linked list of blocks each of which holds
diff --git a/src/mscorlib/shared/System/ValueTuple.cs b/src/mscorlib/shared/System/ValueTuple.cs
index e0cd02e914..3464f2781c 100644
--- a/src/mscorlib/shared/System/ValueTuple.cs
+++ b/src/mscorlib/shared/System/ValueTuple.cs
@@ -29,6 +29,7 @@ namespace System
     /// - their members (such as Item1, Item2, etc) are fields rather than properties.
     /// </summary>
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]  
     public struct ValueTuple
         : IEquatable<ValueTuple>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple>, IValueTupleInternal, ITuple
     {
@@ -298,6 +299,7 @@ namespace System
     /// <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]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]  
     public struct ValueTuple<T1>
         : IEquatable<ValueTuple<T1>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1>>, IValueTupleInternal, ITuple
     {
@@ -464,6 +466,7 @@ namespace System
     /// <typeparam name="T2">The type of the tuple's second component.</typeparam>
     [Serializable]
     [StructLayout(LayoutKind.Auto)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]  
     public struct ValueTuple<T1, T2>
         : IEquatable<ValueTuple<T1, T2>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2>>, IValueTupleInternal, ITuple
     {
@@ -674,6 +677,7 @@ namespace System
     /// <typeparam name="T3">The type of the tuple's third component.</typeparam>
     [Serializable]
     [StructLayout(LayoutKind.Auto)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]  
     public struct ValueTuple<T1, T2, T3>
         : IEquatable<ValueTuple<T1, T2, T3>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2, T3>>, IValueTupleInternal, ITuple
     {
@@ -882,6 +886,7 @@ namespace System
     /// <typeparam name="T4">The type of the tuple's fourth component.</typeparam>
     [Serializable]
     [StructLayout(LayoutKind.Auto)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]  
     public struct ValueTuple<T1, T2, T3, T4>
         : IEquatable<ValueTuple<T1, T2, T3, T4>>, IStructuralEquatable, IStructuralComparable, IComparable, IComparable<ValueTuple<T1, T2, T3, T4>>, IValueTupleInternal, ITuple
     {
@@ -1109,6 +1114,7 @@ namespace System
     /// <typeparam name="T5">The type of the tuple's fifth component.</typeparam>
     [Serializable]
     [StructLayout(LayoutKind.Auto)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]  
     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
     {
@@ -1355,6 +1361,7 @@ namespace System
     /// <typeparam name="T6">The type of the tuple's sixth component.</typeparam>
     [Serializable]
     [StructLayout(LayoutKind.Auto)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]  
     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
     {
@@ -1620,6 +1627,7 @@ namespace System
     /// <typeparam name="T7">The type of the tuple's seventh component.</typeparam>
     [Serializable]
     [StructLayout(LayoutKind.Auto)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]  
     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
     {
@@ -1904,6 +1912,7 @@ namespace System
     /// <typeparam name="TRest">The type of the tuple's eighth component.</typeparam>
     [Serializable]
     [StructLayout(LayoutKind.Auto)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]  
     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
     where TRest : struct
diff --git a/src/mscorlib/shared/System/Version.cs b/src/mscorlib/shared/System/Version.cs
index 54b2052ddb..b88db7e6b4 100644
--- a/src/mscorlib/shared/System/Version.cs
+++ b/src/mscorlib/shared/System/Version.cs
@@ -16,6 +16,7 @@ namespace System
     // specified component.
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public sealed class Version : ICloneable, IComparable
         , IComparable<Version>, IEquatable<Version>
     {
diff --git a/src/mscorlib/src/System/AggregateException.cs b/src/mscorlib/src/System/AggregateException.cs
index 22bc323215..4f87357c20 100644
--- a/src/mscorlib/src/System/AggregateException.cs
+++ b/src/mscorlib/src/System/AggregateException.cs
@@ -30,6 +30,7 @@ namespace System
     /// </remarks>
     [Serializable]
     [DebuggerDisplay("Count = {InnerExceptionCount}")]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class AggregateException : Exception
     {
         private ReadOnlyCollection<Exception> m_innerExceptions; // Complete set of exceptions.
diff --git a/src/mscorlib/src/System/Array.cs b/src/mscorlib/src/System/Array.cs
index fcfeb94675..62a4ecf16e 100644
--- a/src/mscorlib/src/System/Array.cs
+++ b/src/mscorlib/src/System/Array.cs
@@ -26,6 +26,7 @@ namespace System
     // Note that we make a T[] (single-dimensional w/ zero as the lower bound) implement both 
     // IList<U> and IReadOnlyList<U>, where T : U dynamically.  See the SZArrayHelper class for details.
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public abstract class Array : ICloneable, IList, IStructuralComparable, IStructuralEquatable
     {
         // This ctor exists solely to prevent C# from generating a protected .ctor that violates the surface area. I really want this to be a
diff --git a/src/mscorlib/src/System/ArraySegment.cs b/src/mscorlib/src/System/ArraySegment.cs
index 664352708d..d515b468da 100644
--- a/src/mscorlib/src/System/ArraySegment.cs
+++ b/src/mscorlib/src/System/ArraySegment.cs
@@ -26,6 +26,7 @@ namespace System
     // three fields from an ArraySegment may not see the same ArraySegment from one call to another
     // (ie, users could assign a new value to the old location).  
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct ArraySegment<T> : IList<T>, IReadOnlyList<T>
     {
         // Do not replace the array allocation with Array.Empty. We don't want to have the overhead of
diff --git a/src/mscorlib/src/System/Attribute.cs b/src/mscorlib/src/System/Attribute.cs
index baa9a71638..23fd9aaaaf 100644
--- a/src/mscorlib/src/System/Attribute.cs
+++ b/src/mscorlib/src/System/Attribute.cs
@@ -17,6 +17,7 @@ namespace System
 {
     [Serializable]
     [AttributeUsageAttribute(AttributeTargets.All, Inherited = true, AllowMultiple = false)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public abstract class Attribute
     {
         #region Private Statics
diff --git a/src/mscorlib/src/System/Boolean.cs b/src/mscorlib/src/System/Boolean.cs
index 59cab74456..a1f5064964 100644
--- a/src/mscorlib/src/System/Boolean.cs
+++ b/src/mscorlib/src/System/Boolean.cs
@@ -21,6 +21,7 @@ namespace System
     // The Boolean class provides the
     // object representation of the boolean primitive type.
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Boolean : IComparable, IConvertible, IComparable<Boolean>, IEquatable<Boolean>
     {
         //
diff --git a/src/mscorlib/src/System/Byte.cs b/src/mscorlib/src/System/Byte.cs
index da3b790ac6..fafdcbb535 100644
--- a/src/mscorlib/src/System/Byte.cs
+++ b/src/mscorlib/src/System/Byte.cs
@@ -25,6 +25,7 @@ namespace System
     // 
     [Serializable]
     [System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Byte : IComparable, IFormattable, IConvertible
             , IComparable<Byte>, IEquatable<Byte>
     {
diff --git a/src/mscorlib/src/System/Collections/Generic/Comparer.cs b/src/mscorlib/src/System/Collections/Generic/Comparer.cs
index e163faa80f..47c241500d 100644
--- a/src/mscorlib/src/System/Collections/Generic/Comparer.cs
+++ b/src/mscorlib/src/System/Collections/Generic/Comparer.cs
@@ -18,6 +18,7 @@ namespace System.Collections.Generic
 {
     [Serializable]
     [TypeDependencyAttribute("System.Collections.Generic.ObjectComparer`1")]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public abstract class Comparer<T> : IComparer, IComparer<T>
     {
         // To minimize generic instantiation overhead of creating the comparer per type, we keep the generic portion of the code as small
@@ -52,6 +53,7 @@ namespace System.Collections.Generic
     // means another generic instantiation, which can be costly esp.
     // for value types.
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class GenericComparer<T> : Comparer<T> where T : IComparable<T>
     {
         public override int Compare(T x, T y)
@@ -74,6 +76,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class NullableComparer<T> : Comparer<T?> where T : struct, IComparable<T>
     {
         public override int Compare(T? x, T? y)
@@ -96,6 +99,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class ObjectComparer<T> : Comparer<T>
     {
         public override int Compare(T x, T y)
@@ -132,6 +136,7 @@ namespace System.Collections.Generic
     // since we want to serialize as ObjectComparer for
     // back-compat reasons (see below).
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class Int32EnumComparer<T> : Comparer<T>, ISerializable where T : struct
     {
         public Int32EnumComparer()
@@ -167,6 +172,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class UInt32EnumComparer<T> : Comparer<T>, ISerializable where T : struct
     {
         public UInt32EnumComparer()
@@ -198,6 +204,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class Int64EnumComparer<T> : Comparer<T>, ISerializable where T : struct
     {
         public Int64EnumComparer()
@@ -226,6 +233,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class UInt64EnumComparer<T> : Comparer<T>, ISerializable where T : struct
     {
         public UInt64EnumComparer()
diff --git a/src/mscorlib/src/System/Collections/Generic/Dictionary.cs b/src/mscorlib/src/System/Collections/Generic/Dictionary.cs
index cd33428ca1..34ee7a3ee4 100644
--- a/src/mscorlib/src/System/Collections/Generic/Dictionary.cs
+++ b/src/mscorlib/src/System/Collections/Generic/Dictionary.cs
@@ -52,6 +52,7 @@ namespace System.Collections.Generic
     [DebuggerTypeProxy(typeof(Mscorlib_DictionaryDebugView<,>))]
     [DebuggerDisplay("Count = {Count}")]
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public class Dictionary<TKey, TValue> : IDictionary<TKey, TValue>, IDictionary, IReadOnlyDictionary<TKey, TValue>, ISerializable, IDeserializationCallback
     {
         private struct Entry
diff --git a/src/mscorlib/src/System/Collections/Generic/EqualityComparer.cs b/src/mscorlib/src/System/Collections/Generic/EqualityComparer.cs
index d6b213c9d7..760c9d10b2 100644
--- a/src/mscorlib/src/System/Collections/Generic/EqualityComparer.cs
+++ b/src/mscorlib/src/System/Collections/Generic/EqualityComparer.cs
@@ -17,6 +17,7 @@ namespace System.Collections.Generic
 {
     [Serializable]
     [TypeDependencyAttribute("System.Collections.Generic.ObjectEqualityComparer`1")]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public abstract class EqualityComparer<T> : IEqualityComparer, IEqualityComparer<T>
     {
         // To minimize generic instantiation overhead of creating the comparer per type, we keep the generic portion of the code as small
@@ -69,6 +70,7 @@ namespace System.Collections.Generic
     // The methods in this class look identical to the inherited methods, but the calls
     // to Equal bind to IEquatable<T>.Equals(T) instead of Object.Equals(Object)
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal class GenericEqualityComparer<T> : EqualityComparer<T> where T : IEquatable<T>
     {
         [Pure]
@@ -137,6 +139,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class NullableEqualityComparer<T> : EqualityComparer<T?> where T : struct, IEquatable<T>
     {
         [Pure]
@@ -203,6 +206,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class ObjectEqualityComparer<T> : EqualityComparer<T>
     {
         [Pure]
@@ -275,6 +279,7 @@ namespace System.Collections.Generic
     // keep the perofrmance not affected till we hit collision threshold and then we switch to the comparer which is using 
     // randomized string hashing GenericEqualityComparer<string>
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal class NonRandomizedStringEqualityComparer : GenericEqualityComparer<string>
     {
         private static IEqualityComparer<string> s_nonRandomizedComparer;
@@ -302,6 +307,7 @@ namespace System.Collections.Generic
     // Performance of IndexOf on byte array is very important for some scenarios.
     // We will call the C runtime function memchr, which is optimized.
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class ByteEqualityComparer : EqualityComparer<byte>
     {
         [Pure]
@@ -353,6 +359,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal class EnumEqualityComparer<T> : EqualityComparer<T>, ISerializable where T : struct
     {
         [Pure]
@@ -416,6 +423,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class SByteEnumEqualityComparer<T> : EnumEqualityComparer<T> where T : struct
     {
         public SByteEnumEqualityComparer() { }
@@ -432,6 +440,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class ShortEnumEqualityComparer<T> : EnumEqualityComparer<T>, ISerializable where T : struct
     {
         public ShortEnumEqualityComparer() { }
@@ -448,6 +457,7 @@ namespace System.Collections.Generic
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal sealed class LongEnumEqualityComparer<T> : EqualityComparer<T>, ISerializable where T : struct
     {
         [Pure]
diff --git a/src/mscorlib/src/System/Collections/Generic/List.cs b/src/mscorlib/src/System/Collections/Generic/List.cs
index 94e794cfd2..f94acb8fdd 100644
--- a/src/mscorlib/src/System/Collections/Generic/List.cs
+++ b/src/mscorlib/src/System/Collections/Generic/List.cs
@@ -30,6 +30,7 @@ namespace System.Collections.Generic
     [DebuggerTypeProxy(typeof(Mscorlib_CollectionDebugView<>))]
     [DebuggerDisplay("Count = {Count}")]
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class List<T> : IList<T>, System.Collections.IList, IReadOnlyList<T>
     {
         private const int _defaultCapacity = 4;
diff --git a/src/mscorlib/src/System/Collections/ListDictionaryInternal.cs b/src/mscorlib/src/System/Collections/ListDictionaryInternal.cs
index 3f92038d4f..87f180929f 100644
--- a/src/mscorlib/src/System/Collections/ListDictionaryInternal.cs
+++ b/src/mscorlib/src/System/Collections/ListDictionaryInternal.cs
@@ -20,6 +20,7 @@ namespace System.Collections
     ///    will be smaller and faster than a Hashtable if the number of elements is 10 or less.
     ///    This should not be used if performance is important for large numbers of elements.
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     internal class ListDictionaryInternal : IDictionary
     {
         private DictionaryNode head;
diff --git a/src/mscorlib/src/System/Collections/ObjectModel/Collection.cs b/src/mscorlib/src/System/Collections/ObjectModel/Collection.cs
index d9801dfaaf..b2668edf83 100644
--- a/src/mscorlib/src/System/Collections/ObjectModel/Collection.cs
+++ b/src/mscorlib/src/System/Collections/ObjectModel/Collection.cs
@@ -15,6 +15,7 @@ namespace System.Collections.ObjectModel
     [Serializable]
     [DebuggerTypeProxy(typeof(Mscorlib_CollectionDebugView<>))]
     [DebuggerDisplay("Count = {Count}")]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Collection<T> : IList<T>, IList, IReadOnlyList<T>
     {
         private IList<T> items;
diff --git a/src/mscorlib/src/System/Collections/ObjectModel/ReadOnlyCollection.cs b/src/mscorlib/src/System/Collections/ObjectModel/ReadOnlyCollection.cs
index b484879c27..e91ecdc4d3 100644
--- a/src/mscorlib/src/System/Collections/ObjectModel/ReadOnlyCollection.cs
+++ b/src/mscorlib/src/System/Collections/ObjectModel/ReadOnlyCollection.cs
@@ -15,6 +15,7 @@ namespace System.Collections.ObjectModel
     [Serializable]
     [DebuggerTypeProxy(typeof(Mscorlib_CollectionDebugView<>))]
     [DebuggerDisplay("Count = {Count}")]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class ReadOnlyCollection<T> : IList<T>, IList, IReadOnlyList<T>
     {
         private IList<T> list;
diff --git a/src/mscorlib/src/System/Decimal.cs b/src/mscorlib/src/System/Decimal.cs
index ce59a99334..68cd503d28 100644
--- a/src/mscorlib/src/System/Decimal.cs
+++ b/src/mscorlib/src/System/Decimal.cs
@@ -59,6 +59,7 @@ namespace System
     [StructLayout(LayoutKind.Sequential)]
     [Serializable]
     [System.Runtime.Versioning.NonVersionable] // This only applies to field layout
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Decimal : IFormattable, IComparable, IConvertible, IComparable<Decimal>, IEquatable<Decimal>, IDeserializationCallback
     {
         // Sign mask for the flags field. A value of zero in this bit indicates a
diff --git a/src/mscorlib/src/System/Double.cs b/src/mscorlib/src/System/Double.cs
index 30fa1a58b3..b64bb72ed2 100644
--- a/src/mscorlib/src/System/Double.cs
+++ b/src/mscorlib/src/System/Double.cs
@@ -23,6 +23,7 @@ namespace System
 {
     [Serializable]
     [StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Double : IComparable, IFormattable, IConvertible
             , IComparable<Double>, IEquatable<Double>
     {
diff --git a/src/mscorlib/src/System/Enum.cs b/src/mscorlib/src/System/Enum.cs
index 489f36739c..25a4ff34d3 100644
--- a/src/mscorlib/src/System/Enum.cs
+++ b/src/mscorlib/src/System/Enum.cs
@@ -15,6 +15,7 @@ using System.Diagnostics.Contracts;
 namespace System
 {
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public abstract class Enum : ValueType, IComparable, IFormattable, IConvertible
     {
         #region Private Constants
diff --git a/src/mscorlib/src/System/Exception.cs b/src/mscorlib/src/System/Exception.cs
index 8d01b4c461..63bcbeb36d 100644
--- a/src/mscorlib/src/System/Exception.cs
+++ b/src/mscorlib/src/System/Exception.cs
@@ -28,6 +28,7 @@ namespace System
     using System.Diagnostics.Contracts;
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Exception : ISerializable
     {
         private void Init()
diff --git a/src/mscorlib/src/System/Globalization/CompareInfo.cs b/src/mscorlib/src/System/Globalization/CompareInfo.cs
index 593e86415d..cf241a66c8 100644
--- a/src/mscorlib/src/System/Globalization/CompareInfo.cs
+++ b/src/mscorlib/src/System/Globalization/CompareInfo.cs
@@ -34,6 +34,7 @@ namespace System.Globalization
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public partial class CompareInfo : IDeserializationCallback
     {
         // Mask used to check if IndexOf()/LastIndexOf()/IsPrefix()/IsPostfix() has the right flags.
diff --git a/src/mscorlib/src/System/Guid.cs b/src/mscorlib/src/System/Guid.cs
index f64211d5d0..da3473b3d2 100644
--- a/src/mscorlib/src/System/Guid.cs
+++ b/src/mscorlib/src/System/Guid.cs
@@ -18,6 +18,7 @@ namespace System
     [StructLayout(LayoutKind.Sequential)]
     [Serializable]
     [System.Runtime.Versioning.NonVersionable] // This only applies to field layout
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Guid : IFormattable, IComparable
         , IComparable<Guid>, IEquatable<Guid>
     {
diff --git a/src/mscorlib/src/System/Int16.cs b/src/mscorlib/src/System/Int16.cs
index aced05df6d..82e5dd5a38 100644
--- a/src/mscorlib/src/System/Int16.cs
+++ b/src/mscorlib/src/System/Int16.cs
@@ -22,6 +22,7 @@ namespace System
 {
     [Serializable]
     [System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Int16 : IComparable, IFormattable, IConvertible
             , IComparable<Int16>, IEquatable<Int16>
     {
diff --git a/src/mscorlib/src/System/Int32.cs b/src/mscorlib/src/System/Int32.cs
index afee0e42d7..503552117d 100644
--- a/src/mscorlib/src/System/Int32.cs
+++ b/src/mscorlib/src/System/Int32.cs
@@ -22,6 +22,7 @@ namespace System
 {
     [Serializable]
     [System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Int32 : IComparable, IFormattable, IConvertible
             , IComparable<Int32>, IEquatable<Int32>
     {
diff --git a/src/mscorlib/src/System/Int64.cs b/src/mscorlib/src/System/Int64.cs
index 619bf7e5d7..015387233c 100644
--- a/src/mscorlib/src/System/Int64.cs
+++ b/src/mscorlib/src/System/Int64.cs
@@ -21,6 +21,7 @@ namespace System
 {
     [Serializable]
     [System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Int64 : IComparable, IFormattable, IConvertible
             , IComparable<Int64>, IEquatable<Int64>
     {
diff --git a/src/mscorlib/src/System/IntPtr.cs b/src/mscorlib/src/System/IntPtr.cs
index 55c86e3795..4ecf448d52 100644
--- a/src/mscorlib/src/System/IntPtr.cs
+++ b/src/mscorlib/src/System/IntPtr.cs
@@ -23,6 +23,7 @@ namespace System
     using System.Diagnostics.Contracts;
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct IntPtr : IEquatable<IntPtr>, ISerializable
     {
         unsafe private void* _value; // The compiler treats void* closest to uint hence explicit casts are required to preserve int behavior
diff --git a/src/mscorlib/src/System/Nullable.cs b/src/mscorlib/src/System/Nullable.cs
index 31a62ecea8..b9b7c59b31 100644
--- a/src/mscorlib/src/System/Nullable.cs
+++ b/src/mscorlib/src/System/Nullable.cs
@@ -23,6 +23,7 @@ namespace System
     // 
     [Serializable]
     [System.Runtime.Versioning.NonVersionable] // This only applies to field layout
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Nullable<T> where T : struct
     {
         private bool hasValue;
diff --git a/src/mscorlib/src/System/Object.cs b/src/mscorlib/src/System/Object.cs
index a476557911..8df1caa9e5 100644
--- a/src/mscorlib/src/System/Object.cs
+++ b/src/mscorlib/src/System/Object.cs
@@ -34,6 +34,7 @@ namespace System
     [Serializable]
     [ClassInterface(ClassInterfaceType.AutoDual)]
     [System.Runtime.InteropServices.ComVisible(true)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Object
     {
         // Creates a new instance of an Object.
diff --git a/src/mscorlib/src/System/Resources/LooselyLinkedResourceReference.cs b/src/mscorlib/src/System/Resources/LooselyLinkedResourceReference.cs
deleted file mode 100644
index 3179df09b7..0000000000
--- a/src/mscorlib/src/System/Resources/LooselyLinkedResourceReference.cs
+++ /dev/null
@@ -1,85 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-/*============================================================
-**
-** 
-** 
-**
-**
-** Purpose: Provides a localizable way of retrieving a file
-** that is linked into your assembly and/or satellite assembly
-** while also leaving the file on disk for unmanaged tools.
-**
-** 
-===========================================================*/
-
-// Removing LooselyLinkedResourceReference from Whidbey.  We don't
-// yet have any strong customer need for it yet.
-#if LOOSELY_LINKED_RESOURCE_REFERENCE
-
-namespace System.Resources {
-    using System.Reflection;
-    using System.Diagnostics.Contracts;
-    using System.IO;
-    using System.Runtime.InteropServices;
-    using System.Globalization;
-
-    [Serializable]
-
-    public struct LooselyLinkedResourceReference {
-        private String _manifestResourceName;
-        private String _typeName;
-
-        public LooselyLinkedResourceReference(String looselyLinkedResourceName, String typeName)
-        {
-            if (looselyLinkedResourceName == null)
-                throw new ArgumentNullException(nameof(looselyLinkedResourceName));
-            if (typeName == null)
-                throw new ArgumentNullException(nameof(typeName));
-            if (looselyLinkedResourceName.Length == 0)
-                throw new ArgumentException(SR.Argument_EmptyName, nameof(looselyLinkedResourceName));
-            if (typeName.Length == 0)
-                throw new ArgumentException(SR.Argument_EmptyName, nameof(typeName));
-            Contract.EndContractBlock();
-            
-            _manifestResourceName = looselyLinkedResourceName;
-            _typeName = typeName;
-        }
-
-        public String LooselyLinkedResourceName { 
-            get { return _manifestResourceName; }
-        }
-
-        public String TypeName {
-            get { return _typeName; }
-        }
-
-        public Object Resolve(Assembly assembly)
-        {
-            if (assembly == null)
-                throw new ArgumentNullException(nameof(assembly));
-            Contract.EndContractBlock();
-
-            Stream data = assembly.GetManifestResourceStream(_manifestResourceName);
-            if (data == null)
-                throw new MissingManifestResourceException(SR.Format(SR.MissingManifestResource_LooselyLinked, _manifestResourceName, assembly.FullName));
-
-            Type type = Type.GetType(_typeName, true);
-            
-            Object obj = Activator.CreateInstance(type, new Object[] { data });
-            return obj;
-        }
-
-        // For good debugging with tools like ResView
-        public override String ToString()
-        {
-            // This is for debugging only.  Since we use the property names,
-            // this does not need to be localized.
-            return "LooselyLinkedResourceName = \""+ _manifestResourceName +"\", TypeName = \"" + _typeName + "\"";
-        }
-    }
-}
-
-#endif // LOOSELY_LINKED_RESOURCE_REFERENCE
diff --git a/src/mscorlib/src/System/SByte.cs b/src/mscorlib/src/System/SByte.cs
index 9e550936fe..8a0ab3e129 100644
--- a/src/mscorlib/src/System/SByte.cs
+++ b/src/mscorlib/src/System/SByte.cs
@@ -21,6 +21,7 @@ namespace System
     // A place holder class for signed bytes.
     [Serializable]
     [CLSCompliant(false), System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct SByte : IComparable, IFormattable, IConvertible
         , IComparable<SByte>, IEquatable<SByte>
     {
diff --git a/src/mscorlib/src/System/Single.cs b/src/mscorlib/src/System/Single.cs
index 24e6839be6..c94e673c26 100644
--- a/src/mscorlib/src/System/Single.cs
+++ b/src/mscorlib/src/System/Single.cs
@@ -22,6 +22,7 @@ namespace System
 {
     [Serializable]
     [System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public struct Single : IComparable, IFormattable, IConvertible
             , IComparable<Single>, IEquatable<Single>
     {
diff --git a/src/mscorlib/src/System/String.cs b/src/mscorlib/src/System/String.cs
index 0a17c1ee24..c2b7466d92 100644
--- a/src/mscorlib/src/System/String.cs
+++ b/src/mscorlib/src/System/String.cs
@@ -40,6 +40,7 @@ namespace System
     // (indices) are zero-based.
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public sealed partial class String : IComparable, ICloneable, IConvertible, IEnumerable
         , IComparable<String>, IEnumerable<char>, IEquatable<String>
     {
diff --git a/src/mscorlib/src/System/TimeZoneInfo.cs b/src/mscorlib/src/System/TimeZoneInfo.cs
index 8ed7e229c0..cadc9b2704 100644
--- a/src/mscorlib/src/System/TimeZoneInfo.cs
+++ b/src/mscorlib/src/System/TimeZoneInfo.cs
@@ -29,6 +29,7 @@ namespace System
     };
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("System.Core, Version=3.5.0.0, Culture=Neutral, PublicKeyToken=b77a5c561934e089")]
     public sealed partial class TimeZoneInfo : IEquatable<TimeZoneInfo>, ISerializable, IDeserializationCallback
     {
         private enum TimeZoneInfoResult
diff --git a/src/mscorlib/src/System/Tuple.cs b/src/mscorlib/src/System/Tuple.cs
index a118df02bd..87663d186a 100644
--- a/src/mscorlib/src/System/Tuple.cs
+++ b/src/mscorlib/src/System/Tuple.cs
@@ -105,6 +105,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Tuple<T1> : IStructuralEquatable, IStructuralComparable, IComparable, ITupleInternal, ITuple
     {
         private readonly T1 m_Item1;
@@ -204,6 +205,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Tuple<T1, T2> : IStructuralEquatable, IStructuralComparable, IComparable, ITupleInternal, ITuple
     {
         private readonly T1 m_Item1;
@@ -318,6 +320,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Tuple<T1, T2, T3> : IStructuralEquatable, IStructuralComparable, IComparable, ITupleInternal, ITuple
     {
         private readonly T1 m_Item1;
@@ -443,6 +446,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Tuple<T1, T2, T3, T4> : IStructuralEquatable, IStructuralComparable, IComparable, ITupleInternal, ITuple
     {
         private readonly T1 m_Item1;
@@ -579,6 +583,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Tuple<T1, T2, T3, T4, T5> : IStructuralEquatable, IStructuralComparable, IComparable, ITupleInternal, ITuple
     {
         private readonly T1 m_Item1;
@@ -726,6 +731,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Tuple<T1, T2, T3, T4, T5, T6> : IStructuralEquatable, IStructuralComparable, IComparable, ITupleInternal, ITuple
     {
         private readonly T1 m_Item1;
@@ -884,6 +890,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Tuple<T1, T2, T3, T4, T5, T6, T7> : IStructuralEquatable, IStructuralComparable, IComparable, ITupleInternal, ITuple
     {
         private readonly T1 m_Item1;
@@ -1053,6 +1060,7 @@ namespace System
     }
 
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class Tuple<T1, T2, T3, T4, T5, T6, T7, TRest> : IStructuralEquatable, IStructuralComparable, IComparable, ITupleInternal, ITuple
     {
         private readonly T1 m_Item1;
diff --git a/src/mscorlib/src/System/UInt16.cs b/src/mscorlib/src/System/UInt16.cs
index c7be2e9a1f..746ed7ba49 100644
--- a/src/mscorlib/src/System/UInt16.cs
+++ b/src/mscorlib/src/System/UInt16.cs
@@ -21,6 +21,7 @@ namespace System
     // Wrapper for unsigned 16 bit integers.
     [Serializable]
     [CLSCompliant(false), System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public struct UInt16 : IComparable, IFormattable, IConvertible
             , IComparable<UInt16>, IEquatable<UInt16>
     {
diff --git a/src/mscorlib/src/System/UInt32.cs b/src/mscorlib/src/System/UInt32.cs
index 2731047e06..f696816b98 100644
--- a/src/mscorlib/src/System/UInt32.cs
+++ b/src/mscorlib/src/System/UInt32.cs
@@ -23,6 +23,7 @@ namespace System
     // * Wrapper for unsigned 32 bit integers.
     [Serializable]
     [CLSCompliant(false), System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public struct UInt32 : IComparable, IFormattable, IConvertible
         , IComparable<UInt32>, IEquatable<UInt32>
     {
diff --git a/src/mscorlib/src/System/UInt64.cs b/src/mscorlib/src/System/UInt64.cs
index a54bb69ba4..03cdcc5f40 100644
--- a/src/mscorlib/src/System/UInt64.cs
+++ b/src/mscorlib/src/System/UInt64.cs
@@ -21,6 +21,7 @@ namespace System
     // Wrapper for unsigned 64 bit integers.
     [Serializable]
     [CLSCompliant(false), System.Runtime.InteropServices.StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public struct UInt64 : IComparable, IFormattable, IConvertible
             , IComparable<UInt64>, IEquatable<UInt64>
     {
diff --git a/src/mscorlib/src/System/UIntPtr.cs b/src/mscorlib/src/System/UIntPtr.cs
index 08e494297b..0ae3b395bd 100644
--- a/src/mscorlib/src/System/UIntPtr.cs
+++ b/src/mscorlib/src/System/UIntPtr.cs
@@ -21,6 +21,7 @@ namespace System
 
     [Serializable]
     [CLSCompliant(false)]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public struct UIntPtr : IEquatable<UIntPtr>, ISerializable
     {
         unsafe private void* _value;
diff --git a/src/mscorlib/src/System/ValueType.cs b/src/mscorlib/src/System/ValueType.cs
index 0cd08bd26f..e5b5528314 100644
--- a/src/mscorlib/src/System/ValueType.cs
+++ b/src/mscorlib/src/System/ValueType.cs
@@ -19,6 +19,7 @@ using System.Runtime.Versioning;
 namespace System
 {
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public abstract class ValueType
     {
         public override bool Equals(Object obj)
diff --git a/src/mscorlib/src/System/WeakReference.cs b/src/mscorlib/src/System/WeakReference.cs
index 60878b8e1c..d0377e1fc3 100644
--- a/src/mscorlib/src/System/WeakReference.cs
+++ b/src/mscorlib/src/System/WeakReference.cs
@@ -20,6 +20,7 @@ using System.Diagnostics.Contracts;
 namespace System
 {
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     public class WeakReference : ISerializable
     {
         // If you fix bugs here, please fix them in WeakReference<T> at the same time.
diff --git a/src/mscorlib/src/System/WeakReferenceOfT.cs b/src/mscorlib/src/System/WeakReferenceOfT.cs
index fbb6f09098..e5b70805c9 100644
--- a/src/mscorlib/src/System/WeakReferenceOfT.cs
+++ b/src/mscorlib/src/System/WeakReferenceOfT.cs
@@ -20,6 +20,7 @@ using System.Diagnostics.Contracts;
 namespace System
 {
     [Serializable]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")] 
     // This class is sealed to mitigate security issues caused by Object::MemberwiseClone.
     public sealed class WeakReference<T> : ISerializable
         where T : class
diff --git a/src/mscorlib/src/mscorlib.Friends.cs b/src/mscorlib/src/mscorlib.Friends.cs
index b02b4829d9..709ec21191 100644
--- a/src/mscorlib/src/mscorlib.Friends.cs
+++ b/src/mscorlib/src/mscorlib.Friends.cs
@@ -13,3 +13,5 @@ using System.Runtime.CompilerServices;
 // Depends on WindowsRuntimeImportAttribute
 [assembly: InternalsVisibleTo("System.Runtime.WindowsRuntime.UI.Xaml, PublicKey=00000000000000000400000000000000", AllInternalsVisible = false)]
 
+// Cross framework serialization needs access to internals
+[assembly: InternalsVisibleTo("mscorlib, PublicKey=00000000000000000400000000000000", AllInternalsVisible=false)]