Apply changes from https://github.com/mono/mono/pull/12841 to API snapshot

3 files changed, 213 insertions, 0 deletions

diff --git a/profiles/monodroid/mscorlib.cs b/profiles/monodroid/mscorlib.cs
index 355e61d..b7470d4 100644
--- a/profiles/monodroid/mscorlib.cs
+++ b/profiles/monodroid/mscorlib.cs
@@ -3032,6 +3032,24 @@ namespace System
     {
         string ToString(string format, System.IFormatProvider formatProvider);
     }
+    [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+    public readonly partial struct Index : System.IEquatable<System.Index>
+    {
+        private readonly int _dummyPrimitive;
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public Index(int value, bool fromEnd = false) { throw null; }
+        public static System.Index End { get { throw null; } }
+        public bool IsFromEnd { get { throw null; } }
+        public static System.Index Start { get { throw null; } }
+        public int Value { get { throw null; } }
+        public bool Equals(System.Index other) { throw null; }
+        public override bool Equals(object value) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Index FromEnd(int value) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Index FromStart(int value) { throw null; }
+        public override int GetHashCode() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public int GetOffset(int length) { throw null; }
+        public static implicit operator System.Index (int value) { throw null; }
+        public override string ToString() { throw null; }
+    }
     [System.SerializableAttribute]
     public sealed partial class IndexOutOfRangeException : System.SystemException
     {
@@ -3492,23 +3510,31 @@ namespace System
     public static partial class MemoryExtensions
     {
         public static System.ReadOnlyMemory<char> AsMemory(this string text) { throw null; }
+        public static System.ReadOnlyMemory<char> AsMemory(this string text, System.Index startIndex) { throw null; }
         public static System.ReadOnlyMemory<char> AsMemory(this string text, int start) { throw null; }
         public static System.ReadOnlyMemory<char> AsMemory(this string text, int start, int length) { throw null; }
+        public static System.ReadOnlyMemory<char> AsMemory(this string text, System.Range range) { throw null; }
         public static System.Memory<T> AsMemory<T>(this System.ArraySegment<T> segment) { throw null; }
         public static System.Memory<T> AsMemory<T>(this System.ArraySegment<T> segment, int start) { throw null; }
         public static System.Memory<T> AsMemory<T>(this System.ArraySegment<T> segment, int start, int length) { throw null; }
         public static System.Memory<T> AsMemory<T>(this T[] array) { throw null; }
+        public static System.Memory<T> AsMemory<T>(this T[] array, System.Index startIndex) { throw null; }
         public static System.Memory<T> AsMemory<T>(this T[] array, int start) { throw null; }
         public static System.Memory<T> AsMemory<T>(this T[] array, int start, int length) { throw null; }
+        public static System.Memory<T> AsMemory<T>(this T[] array, System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.ReadOnlySpan<char> AsSpan(this string text) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.ReadOnlySpan<char> AsSpan(this string text, int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.ReadOnlySpan<char> AsSpan(this string text, int start, int length) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static int BinarySearch<T>(this System.ReadOnlySpan<T> span, System.IComparable<T> comparable) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static int BinarySearch<T>(this System.Span<T> span, System.IComparable<T> comparable) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static int BinarySearch<T, TComparer>(this System.ReadOnlySpan<T> span, T value, TComparer comparer) where TComparer : System.Collections.Generic.IComparer<T> { throw null; }
@@ -3582,6 +3608,7 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public Memory(T[] array, int start, int length) { throw null; }
         public static System.Memory<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public System.Memory<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public System.Span<T> Span { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
         public void CopyTo(System.Memory<T> destination) { }
@@ -3592,8 +3619,10 @@ namespace System
         public static implicit operator System.ReadOnlyMemory<T> (System.Memory<T> memory) { throw null; }
         public static implicit operator System.Memory<T> (T[] array) { throw null; }
         public System.Buffers.MemoryHandle Pin() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(System.Range range) { throw null; }
         public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Memory<T> destination) { throw null; }
@@ -3931,6 +3960,31 @@ namespace System
         public virtual double NextDouble() { throw null; }
         protected virtual double Sample() { throw null; }
     }
+    [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+    public readonly partial struct Range : System.IEquatable<System.Range>
+    {
+        private readonly int _dummyPrimitive;
+        public Range(System.Index start, System.Index end) { throw null; }
+        public static System.Range All { get { throw null; } }
+        public System.Index End { get { throw null; } }
+        public System.Index Start { get { throw null; } }
+        public static System.Range EndAt(System.Index end) { throw null; }
+        public override bool Equals(object value) { throw null; }
+        public bool Equals(System.Range other) { throw null; }
+        public override int GetHashCode() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Range.OffsetAndLength GetOffsetAndLength(int length) { throw null; }
+        public static System.Range StartAt(System.Index start) { throw null; }
+        public override string ToString() { throw null; }
+        [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+        public readonly partial struct OffsetAndLength
+        {
+            private readonly int _dummyPrimitive;
+            public OffsetAndLength(int offset, int length) { throw null; }
+            public int Length { get { throw null; } }
+            public int Offset { get { throw null; } }
+            public void Deconstruct(out int offset, out int length) { throw null; }
+        }
+    }
     [System.SerializableAttribute]
     public partial class RankException : System.SystemException
     {
@@ -3950,6 +4004,7 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public ReadOnlyMemory(T[] array, int start, int length) { throw null; }
         public static System.ReadOnlyMemory<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public System.ReadOnlyMemory<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public System.ReadOnlySpan<T> Span { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
         public void CopyTo(System.Memory<T> destination) { }
@@ -3959,8 +4014,10 @@ namespace System
         public static implicit operator System.ReadOnlyMemory<T> (System.ArraySegment<T> segment) { throw null; }
         public static implicit operator System.ReadOnlyMemory<T> (T[] array) { throw null; }
         public System.Buffers.MemoryHandle Pin() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(System.Range range) { throw null; }
         public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Memory<T> destination) { throw null; }
@@ -3978,7 +4035,9 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public ReadOnlySpan(T[] array, int start, int length) { throw null; }
         public static System.ReadOnlySpan<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public ref readonly T this[System.Index index] { get { throw null; } }
         public ref readonly T this[int index] { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
+        public System.ReadOnlySpan<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public void CopyTo(System.Span<T> destination) { }
         [System.ObsoleteAttribute("Equals() on ReadOnlySpan will always throw an exception. Use == instead.")]
@@ -3991,8 +4050,10 @@ namespace System
         public static implicit operator System.ReadOnlySpan<T> (System.ArraySegment<T> segment) { throw null; }
         public static implicit operator System.ReadOnlySpan<T> (T[] array) { throw null; }
         public static bool operator !=(System.ReadOnlySpan<T> left, System.ReadOnlySpan<T> right) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(System.Range range) { throw null; }
         public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Span<T> destination) { throw null; }
@@ -4216,7 +4277,9 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public Span(T[] array, int start, int length) { throw null; }
         public static System.Span<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public ref T this[System.Index index] { get { throw null; } }
         public ref T this[int index] { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
+        public System.Span<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public void Clear() { }
         public void CopyTo(System.Span<T> destination) { }
@@ -4232,8 +4295,10 @@ namespace System
         public static implicit operator System.ReadOnlySpan<T> (System.Span<T> span) { throw null; }
         public static implicit operator System.Span<T> (T[] array) { throw null; }
         public static bool operator !=(System.Span<T> left, System.Span<T> right) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Span<T> destination) { throw null; }
@@ -4277,7 +4342,11 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.InternalCall)][System.CLSCompliantAttribute(false)]
         public unsafe String(sbyte* value, int startIndex, int length, System.Text.Encoding enc) { }
         [System.Runtime.CompilerServices.IndexerName("Chars")]
+        public char this[System.Index index] { get { throw null; } }
+        [System.Runtime.CompilerServices.IndexerName("Chars")]
         public char this[int index] { get { throw null; } }
+        [System.Runtime.CompilerServices.IndexerName("Chars")]
+        public string this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public object Clone() { throw null; }
         public static int Compare(System.String strA, int indexA, System.String strB, int indexB, int length) { throw null; }
@@ -4404,8 +4473,10 @@ namespace System
         public bool StartsWith(System.String value) { throw null; }
         public bool StartsWith(System.String value, bool ignoreCase, System.Globalization.CultureInfo culture) { throw null; }
         public bool StartsWith(System.String value, System.StringComparison comparisonType) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.String Substring(System.Index startIndex) { throw null; }
         public System.String Substring(int startIndex) { throw null; }
         public System.String Substring(int startIndex, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.String Substring(System.Range range) { throw null; }
         System.Collections.Generic.IEnumerator<char> System.Collections.Generic.IEnumerable<System.Char>.GetEnumerator() { throw null; }
         System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { throw null; }
         bool System.IConvertible.ToBoolean(System.IFormatProvider provider) { throw null; }
diff --git a/profiles/monotouch/mscorlib.cs b/profiles/monotouch/mscorlib.cs
index 6ceda03..4dd347d 100644
--- a/profiles/monotouch/mscorlib.cs
+++ b/profiles/monotouch/mscorlib.cs
@@ -3012,6 +3012,24 @@ namespace System
     {
         string ToString(string format, System.IFormatProvider formatProvider);
     }
+    [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+    public readonly partial struct Index : System.IEquatable<System.Index>
+    {
+        private readonly int _dummyPrimitive;
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public Index(int value, bool fromEnd = false) { throw null; }
+        public static System.Index End { get { throw null; } }
+        public bool IsFromEnd { get { throw null; } }
+        public static System.Index Start { get { throw null; } }
+        public int Value { get { throw null; } }
+        public bool Equals(System.Index other) { throw null; }
+        public override bool Equals(object value) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Index FromEnd(int value) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Index FromStart(int value) { throw null; }
+        public override int GetHashCode() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public int GetOffset(int length) { throw null; }
+        public static implicit operator System.Index (int value) { throw null; }
+        public override string ToString() { throw null; }
+    }
     [System.SerializableAttribute]
     public sealed partial class IndexOutOfRangeException : System.SystemException
     {
@@ -3472,23 +3490,31 @@ namespace System
     public static partial class MemoryExtensions
     {
         public static System.ReadOnlyMemory<char> AsMemory(this string text) { throw null; }
+        public static System.ReadOnlyMemory<char> AsMemory(this string text, System.Index startIndex) { throw null; }
         public static System.ReadOnlyMemory<char> AsMemory(this string text, int start) { throw null; }
         public static System.ReadOnlyMemory<char> AsMemory(this string text, int start, int length) { throw null; }
+        public static System.ReadOnlyMemory<char> AsMemory(this string text, System.Range range) { throw null; }
         public static System.Memory<T> AsMemory<T>(this System.ArraySegment<T> segment) { throw null; }
         public static System.Memory<T> AsMemory<T>(this System.ArraySegment<T> segment, int start) { throw null; }
         public static System.Memory<T> AsMemory<T>(this System.ArraySegment<T> segment, int start, int length) { throw null; }
         public static System.Memory<T> AsMemory<T>(this T[] array) { throw null; }
+        public static System.Memory<T> AsMemory<T>(this T[] array, System.Index startIndex) { throw null; }
         public static System.Memory<T> AsMemory<T>(this T[] array, int start) { throw null; }
         public static System.Memory<T> AsMemory<T>(this T[] array, int start, int length) { throw null; }
+        public static System.Memory<T> AsMemory<T>(this T[] array, System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.ReadOnlySpan<char> AsSpan(this string text) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.ReadOnlySpan<char> AsSpan(this string text, int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.ReadOnlySpan<char> AsSpan(this string text, int start, int length) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static int BinarySearch<T>(this System.ReadOnlySpan<T> span, System.IComparable<T> comparable) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static int BinarySearch<T>(this System.Span<T> span, System.IComparable<T> comparable) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static int BinarySearch<T, TComparer>(this System.ReadOnlySpan<T> span, T value, TComparer comparer) where TComparer : System.Collections.Generic.IComparer<T> { throw null; }
@@ -3562,6 +3588,7 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public Memory(T[] array, int start, int length) { throw null; }
         public static System.Memory<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public System.Memory<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public System.Span<T> Span { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
         public void CopyTo(System.Memory<T> destination) { }
@@ -3572,8 +3599,10 @@ namespace System
         public static implicit operator System.ReadOnlyMemory<T> (System.Memory<T> memory) { throw null; }
         public static implicit operator System.Memory<T> (T[] array) { throw null; }
         public System.Buffers.MemoryHandle Pin() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(System.Range range) { throw null; }
         public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Memory<T> destination) { throw null; }
@@ -3911,6 +3940,31 @@ namespace System
         public virtual double NextDouble() { throw null; }
         protected virtual double Sample() { throw null; }
     }
+    [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+    public readonly partial struct Range : System.IEquatable<System.Range>
+    {
+        private readonly int _dummyPrimitive;
+        public Range(System.Index start, System.Index end) { throw null; }
+        public static System.Range All { get { throw null; } }
+        public System.Index End { get { throw null; } }
+        public System.Index Start { get { throw null; } }
+        public static System.Range EndAt(System.Index end) { throw null; }
+        public override bool Equals(object value) { throw null; }
+        public bool Equals(System.Range other) { throw null; }
+        public override int GetHashCode() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Range.OffsetAndLength GetOffsetAndLength(int length) { throw null; }
+        public static System.Range StartAt(System.Index start) { throw null; }
+        public override string ToString() { throw null; }
+        [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+        public readonly partial struct OffsetAndLength
+        {
+            private readonly int _dummyPrimitive;
+            public OffsetAndLength(int offset, int length) { throw null; }
+            public int Length { get { throw null; } }
+            public int Offset { get { throw null; } }
+            public void Deconstruct(out int offset, out int length) { throw null; }
+        }
+    }
     [System.SerializableAttribute]
     public partial class RankException : System.SystemException
     {
@@ -3930,6 +3984,7 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public ReadOnlyMemory(T[] array, int start, int length) { throw null; }
         public static System.ReadOnlyMemory<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public System.ReadOnlyMemory<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public System.ReadOnlySpan<T> Span { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
         public void CopyTo(System.Memory<T> destination) { }
@@ -3939,8 +3994,10 @@ namespace System
         public static implicit operator System.ReadOnlyMemory<T> (System.ArraySegment<T> segment) { throw null; }
         public static implicit operator System.ReadOnlyMemory<T> (T[] array) { throw null; }
         public System.Buffers.MemoryHandle Pin() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(System.Range range) { throw null; }
         public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Memory<T> destination) { throw null; }
@@ -3958,7 +4015,9 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public ReadOnlySpan(T[] array, int start, int length) { throw null; }
         public static System.ReadOnlySpan<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public ref readonly T this[System.Index index] { get { throw null; } }
         public ref readonly T this[int index] { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
+        public System.ReadOnlySpan<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public void CopyTo(System.Span<T> destination) { }
         [System.ObsoleteAttribute("Equals() on ReadOnlySpan will always throw an exception. Use == instead.")]
@@ -3971,8 +4030,10 @@ namespace System
         public static implicit operator System.ReadOnlySpan<T> (System.ArraySegment<T> segment) { throw null; }
         public static implicit operator System.ReadOnlySpan<T> (T[] array) { throw null; }
         public static bool operator !=(System.ReadOnlySpan<T> left, System.ReadOnlySpan<T> right) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(System.Range range) { throw null; }
         public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Span<T> destination) { throw null; }
@@ -4196,7 +4257,9 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public Span(T[] array, int start, int length) { throw null; }
         public static System.Span<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public ref T this[System.Index index] { get { throw null; } }
         public ref T this[int index] { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
+        public System.Span<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public void Clear() { }
         public void CopyTo(System.Span<T> destination) { }
@@ -4212,8 +4275,10 @@ namespace System
         public static implicit operator System.ReadOnlySpan<T> (System.Span<T> span) { throw null; }
         public static implicit operator System.Span<T> (T[] array) { throw null; }
         public static bool operator !=(System.Span<T> left, System.Span<T> right) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Span<T> destination) { throw null; }
@@ -4257,7 +4322,11 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.InternalCall)][System.CLSCompliantAttribute(false)]
         public unsafe String(sbyte* value, int startIndex, int length, System.Text.Encoding enc) { }
         [System.Runtime.CompilerServices.IndexerName("Chars")]
+        public char this[System.Index index] { get { throw null; } }
+        [System.Runtime.CompilerServices.IndexerName("Chars")]
         public char this[int index] { get { throw null; } }
+        [System.Runtime.CompilerServices.IndexerName("Chars")]
+        public string this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public object Clone() { throw null; }
         public static int Compare(System.String strA, int indexA, System.String strB, int indexB, int length) { throw null; }
@@ -4384,8 +4453,10 @@ namespace System
         public bool StartsWith(System.String value) { throw null; }
         public bool StartsWith(System.String value, bool ignoreCase, System.Globalization.CultureInfo culture) { throw null; }
         public bool StartsWith(System.String value, System.StringComparison comparisonType) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.String Substring(System.Index startIndex) { throw null; }
         public System.String Substring(int startIndex) { throw null; }
         public System.String Substring(int startIndex, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.String Substring(System.Range range) { throw null; }
         System.Collections.Generic.IEnumerator<char> System.Collections.Generic.IEnumerable<System.Char>.GetEnumerator() { throw null; }
         System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { throw null; }
         bool System.IConvertible.ToBoolean(System.IFormatProvider provider) { throw null; }
diff --git a/profiles/net_4_x/mscorlib.cs b/profiles/net_4_x/mscorlib.cs
index dec7da2..d99f1f2 100644
--- a/profiles/net_4_x/mscorlib.cs
+++ b/profiles/net_4_x/mscorlib.cs
@@ -3078,6 +3078,24 @@ namespace System
     {
         string ToString(string format, System.IFormatProvider formatProvider);
     }
+    [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+    public readonly partial struct Index : System.IEquatable<System.Index>
+    {
+        private readonly int _dummyPrimitive;
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public Index(int value, bool fromEnd = false) { throw null; }
+        public static System.Index End { get { throw null; } }
+        public bool IsFromEnd { get { throw null; } }
+        public static System.Index Start { get { throw null; } }
+        public int Value { get { throw null; } }
+        public bool Equals(System.Index other) { throw null; }
+        public override bool Equals(object value) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Index FromEnd(int value) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Index FromStart(int value) { throw null; }
+        public override int GetHashCode() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public int GetOffset(int length) { throw null; }
+        public static implicit operator System.Index (int value) { throw null; }
+        public override string ToString() { throw null; }
+    }
     [System.SerializableAttribute]
     public sealed partial class IndexOutOfRangeException : System.SystemException
     {
@@ -3538,23 +3556,31 @@ namespace System
     public static partial class MemoryExtensions
     {
         public static System.ReadOnlyMemory<char> AsMemory(this string text) { throw null; }
+        public static System.ReadOnlyMemory<char> AsMemory(this string text, System.Index startIndex) { throw null; }
         public static System.ReadOnlyMemory<char> AsMemory(this string text, int start) { throw null; }
         public static System.ReadOnlyMemory<char> AsMemory(this string text, int start, int length) { throw null; }
+        public static System.ReadOnlyMemory<char> AsMemory(this string text, System.Range range) { throw null; }
         public static System.Memory<T> AsMemory<T>(this System.ArraySegment<T> segment) { throw null; }
         public static System.Memory<T> AsMemory<T>(this System.ArraySegment<T> segment, int start) { throw null; }
         public static System.Memory<T> AsMemory<T>(this System.ArraySegment<T> segment, int start, int length) { throw null; }
         public static System.Memory<T> AsMemory<T>(this T[] array) { throw null; }
+        public static System.Memory<T> AsMemory<T>(this T[] array, System.Index startIndex) { throw null; }
         public static System.Memory<T> AsMemory<T>(this T[] array, int start) { throw null; }
         public static System.Memory<T> AsMemory<T>(this T[] array, int start, int length) { throw null; }
+        public static System.Memory<T> AsMemory<T>(this T[] array, System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.ReadOnlySpan<char> AsSpan(this string text) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.ReadOnlySpan<char> AsSpan(this string text, int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.ReadOnlySpan<char> AsSpan(this string text, int start, int length) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this System.ArraySegment<T> segment, System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static System.Span<T> AsSpan<T>(this T[] array, System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static int BinarySearch<T>(this System.ReadOnlySpan<T> span, System.IComparable<T> comparable) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static int BinarySearch<T>(this System.Span<T> span, System.IComparable<T> comparable) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public static int BinarySearch<T, TComparer>(this System.ReadOnlySpan<T> span, T value, TComparer comparer) where TComparer : System.Collections.Generic.IComparer<T> { throw null; }
@@ -3628,6 +3654,7 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public Memory(T[] array, int start, int length) { throw null; }
         public static System.Memory<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public System.Memory<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public System.Span<T> Span { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
         public void CopyTo(System.Memory<T> destination) { }
@@ -3638,8 +3665,10 @@ namespace System
         public static implicit operator System.ReadOnlyMemory<T> (System.Memory<T> memory) { throw null; }
         public static implicit operator System.Memory<T> (T[] array) { throw null; }
         public System.Buffers.MemoryHandle Pin() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Memory<T> Slice(System.Range range) { throw null; }
         public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Memory<T> destination) { throw null; }
@@ -3977,6 +4006,31 @@ namespace System
         public virtual double NextDouble() { throw null; }
         protected virtual double Sample() { throw null; }
     }
+    [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+    public readonly partial struct Range : System.IEquatable<System.Range>
+    {
+        private readonly int _dummyPrimitive;
+        public Range(System.Index start, System.Index end) { throw null; }
+        public static System.Range All { get { throw null; } }
+        public System.Index End { get { throw null; } }
+        public System.Index Start { get { throw null; } }
+        public static System.Range EndAt(System.Index end) { throw null; }
+        public override bool Equals(object value) { throw null; }
+        public bool Equals(System.Range other) { throw null; }
+        public override int GetHashCode() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Range.OffsetAndLength GetOffsetAndLength(int length) { throw null; }
+        public static System.Range StartAt(System.Index start) { throw null; }
+        public override string ToString() { throw null; }
+        [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+        public readonly partial struct OffsetAndLength
+        {
+            private readonly int _dummyPrimitive;
+            public OffsetAndLength(int offset, int length) { throw null; }
+            public int Length { get { throw null; } }
+            public int Offset { get { throw null; } }
+            public void Deconstruct(out int offset, out int length) { throw null; }
+        }
+    }
     [System.SerializableAttribute]
     public partial class RankException : System.SystemException
     {
@@ -3996,6 +4050,7 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public ReadOnlyMemory(T[] array, int start, int length) { throw null; }
         public static System.ReadOnlyMemory<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public System.ReadOnlyMemory<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public System.ReadOnlySpan<T> Span { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
         public void CopyTo(System.Memory<T> destination) { }
@@ -4005,8 +4060,10 @@ namespace System
         public static implicit operator System.ReadOnlyMemory<T> (System.ArraySegment<T> segment) { throw null; }
         public static implicit operator System.ReadOnlyMemory<T> (T[] array) { throw null; }
         public System.Buffers.MemoryHandle Pin() { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlyMemory<T> Slice(System.Range range) { throw null; }
         public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Memory<T> destination) { throw null; }
@@ -4024,7 +4081,9 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public ReadOnlySpan(T[] array, int start, int length) { throw null; }
         public static System.ReadOnlySpan<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public ref readonly T this[System.Index index] { get { throw null; } }
         public ref readonly T this[int index] { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
+        public System.ReadOnlySpan<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public void CopyTo(System.Span<T> destination) { }
         [System.ObsoleteAttribute("Equals() on ReadOnlySpan will always throw an exception. Use == instead.")]
@@ -4037,8 +4096,10 @@ namespace System
         public static implicit operator System.ReadOnlySpan<T> (System.ArraySegment<T> segment) { throw null; }
         public static implicit operator System.ReadOnlySpan<T> (T[] array) { throw null; }
         public static bool operator !=(System.ReadOnlySpan<T> left, System.ReadOnlySpan<T> right) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.ReadOnlySpan<T> Slice(System.Range range) { throw null; }
         public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Span<T> destination) { throw null; }
@@ -4262,7 +4323,9 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public Span(T[] array, int start, int length) { throw null; }
         public static System.Span<T> Empty { get { throw null; } }
         public bool IsEmpty { get { throw null; } }
+        public ref T this[System.Index index] { get { throw null; } }
         public ref T this[int index] { [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]get { throw null; } }
+        public System.Span<T> this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public void Clear() { }
         public void CopyTo(System.Span<T> destination) { }
@@ -4278,8 +4341,10 @@ namespace System
         public static implicit operator System.ReadOnlySpan<T> (System.Span<T> span) { throw null; }
         public static implicit operator System.Span<T> (T[] array) { throw null; }
         public static bool operator !=(System.Span<T> left, System.Span<T> right) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(System.Index startIndex) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(int start) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(int start, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.Span<T> Slice(System.Range range) { throw null; }
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public T[] ToArray() { throw null; }
         public override string ToString() { throw null; }
         public bool TryCopyTo(System.Span<T> destination) { throw null; }
@@ -4323,7 +4388,11 @@ namespace System
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.InternalCall)][System.CLSCompliantAttribute(false)]
         public unsafe String(sbyte* value, int startIndex, int length, System.Text.Encoding enc) { }
         [System.Runtime.CompilerServices.IndexerName("Chars")]
+        public char this[System.Index index] { get { throw null; } }
+        [System.Runtime.CompilerServices.IndexerName("Chars")]
         public char this[int index] { get { throw null; } }
+        [System.Runtime.CompilerServices.IndexerName("Chars")]
+        public string this[System.Range range] { get { throw null; } }
         public int Length { get { throw null; } }
         public object Clone() { throw null; }
         public static int Compare(System.String strA, int indexA, System.String strB, int indexB, int length) { throw null; }
@@ -4450,8 +4519,10 @@ namespace System
         public bool StartsWith(System.String value) { throw null; }
         public bool StartsWith(System.String value, bool ignoreCase, System.Globalization.CultureInfo culture) { throw null; }
         public bool StartsWith(System.String value, System.StringComparison comparisonType) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.String Substring(System.Index startIndex) { throw null; }
         public System.String Substring(int startIndex) { throw null; }
         public System.String Substring(int startIndex, int length) { throw null; }
+        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]public System.String Substring(System.Range range) { throw null; }
         System.Collections.Generic.IEnumerator<char> System.Collections.Generic.IEnumerable<System.Char>.GetEnumerator() { throw null; }
         System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { throw null; }
         bool System.IConvertible.ToBoolean(System.IFormatProvider provider) { throw null; }