From 5b00a73b86470d77103808e2b59b3c42ecf46223 Mon Sep 17 00:00:00 2001
From: Santiago Fernandez Madero <safern@microsoft.com>
Date: Wed, 27 Mar 2019 10:54:45 -0700
Subject: [PATCH] Nullable: System.Char (#23480)

---
 src/System.Private.CoreLib/shared/System/Char.cs | 40 +++++++++++++-----------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/src/System.Private.CoreLib/shared/System/Char.cs b/src/System.Private.CoreLib/shared/System/Char.cs
index 50dd092..80dce56 100644
--- a/src/System.Private.CoreLib/shared/System/Char.cs
+++ b/src/System.Private.CoreLib/shared/System/Char.cs
@@ -12,6 +12,7 @@
 **
 ===========================================================*/
 
+#nullable enable
 using System.Diagnostics;
 using System.Globalization;
 using System.Runtime.InteropServices;
@@ -108,7 +109,7 @@ namespace System
 
         // Used for comparing two boxed Char objects.
         //
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             if (!(obj is char))
             {
@@ -129,7 +130,7 @@ namespace System
         // null is considered to be less than any instance.
         // If object is not of type Char, this method throws an ArgumentException.
         //
-        public int CompareTo(object value)
+        public int CompareTo(object? value)
         {
             if (value == null)
             {
@@ -154,7 +155,7 @@ namespace System
             return char.ToString(m_value);
         }
 
-        public string ToString(IFormatProvider provider)
+        public string ToString(IFormatProvider? provider)
         {
             return char.ToString(m_value);
         }
@@ -183,7 +184,7 @@ namespace System
             return s[0];
         }
 
-        public static bool TryParse(string s, out char result)
+        public static bool TryParse(string? s, out char result)
         {
             result = '\0';
             if (s == null)
@@ -426,80 +427,81 @@ namespace System
         }
 
 
-        bool IConvertible.ToBoolean(IFormatProvider provider)
+        bool IConvertible.ToBoolean(IFormatProvider? provider)
         {
             throw new InvalidCastException(SR.Format(SR.InvalidCast_FromTo, "Char", "Boolean"));
         }
 
-        char IConvertible.ToChar(IFormatProvider provider)
+        char IConvertible.ToChar(IFormatProvider? provider)
         {
             return m_value;
         }
 
-        sbyte IConvertible.ToSByte(IFormatProvider provider)
+        sbyte IConvertible.ToSByte(IFormatProvider? provider)
         {
             return Convert.ToSByte(m_value);
         }
 
-        byte IConvertible.ToByte(IFormatProvider provider)
+        byte IConvertible.ToByte(IFormatProvider? provider)
         {
             return Convert.ToByte(m_value);
         }
 
-        short IConvertible.ToInt16(IFormatProvider provider)
+        short IConvertible.ToInt16(IFormatProvider? provider)
         {
             return Convert.ToInt16(m_value);
         }
 
-        ushort IConvertible.ToUInt16(IFormatProvider provider)
+        ushort IConvertible.ToUInt16(IFormatProvider? provider)
         {
             return Convert.ToUInt16(m_value);
         }
 
-        int IConvertible.ToInt32(IFormatProvider provider)
+        int IConvertible.ToInt32(IFormatProvider? provider)
         {
             return Convert.ToInt32(m_value);
         }
 
-        uint IConvertible.ToUInt32(IFormatProvider provider)
+        uint IConvertible.ToUInt32(IFormatProvider? provider)
         {
             return Convert.ToUInt32(m_value);
         }
 
-        long IConvertible.ToInt64(IFormatProvider provider)
+        long IConvertible.ToInt64(IFormatProvider? provider)
         {
             return Convert.ToInt64(m_value);
         }
 
-        ulong IConvertible.ToUInt64(IFormatProvider provider)
+        ulong IConvertible.ToUInt64(IFormatProvider? provider)
         {
             return Convert.ToUInt64(m_value);
         }
 
-        float IConvertible.ToSingle(IFormatProvider provider)
+        float IConvertible.ToSingle(IFormatProvider? provider)
         {
             throw new InvalidCastException(SR.Format(SR.InvalidCast_FromTo, "Char", "Single"));
         }
 
-        double IConvertible.ToDouble(IFormatProvider provider)
+        double IConvertible.ToDouble(IFormatProvider? provider)
         {
             throw new InvalidCastException(SR.Format(SR.InvalidCast_FromTo, "Char", "Double"));
         }
 
-        decimal IConvertible.ToDecimal(IFormatProvider provider)
+        decimal IConvertible.ToDecimal(IFormatProvider? provider)
         {
             throw new InvalidCastException(SR.Format(SR.InvalidCast_FromTo, "Char", "Decimal"));
         }
 
-        DateTime IConvertible.ToDateTime(IFormatProvider provider)
+        DateTime IConvertible.ToDateTime(IFormatProvider? provider)
         {
             throw new InvalidCastException(SR.Format(SR.InvalidCast_FromTo, "Char", "DateTime"));
         }
 
-        object IConvertible.ToType(Type type, IFormatProvider provider)
+        object IConvertible.ToType(Type type, IFormatProvider? provider)
         {
             return Convert.DefaultToType((IConvertible)this, type, provider);
         }
+
         public static bool IsControl(char c)
         {
             if (IsLatin1(c))
-- 
2.7.4