From cf13110aa34d6dfc0a588eeb4b91af626897be21 Mon Sep 17 00:00:00 2001
From: James Ko <jamesqko@gmail.com>
Date: Mon, 4 Jul 2016 20:16:44 -0400
Subject: [PATCH] Fix CoreFX test failures

Commit migrated from https://github.com/dotnet/coreclr/commit/4fd1bfef80fbd4ccb7625196cd841f4fa6415282
---
 .../src/mscorlib/src/System/Text/ASCIIEncoding.cs        |  5 -----
 .../src/mscorlib/src/System/Text/EncodingForwarder.cs    | 16 ++++++++++++----
 src/coreclr/src/mscorlib/src/System/Text/UTF8Encoding.cs |  2 --
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/coreclr/src/mscorlib/src/System/Text/ASCIIEncoding.cs b/src/coreclr/src/mscorlib/src/System/Text/ASCIIEncoding.cs
index bf94b81..4e2b798 100644
--- a/src/coreclr/src/mscorlib/src/System/Text/ASCIIEncoding.cs
+++ b/src/coreclr/src/mscorlib/src/System/Text/ASCIIEncoding.cs
@@ -66,8 +66,6 @@ namespace System.Text
         [System.Security.SecuritySafeCritical]  // auto-generated
         public override int GetByteCount(String chars)
         {
-            // NOTE: If chars is null, this will throw an ArgumentNullException
-            // with the parameter name "s" rather than "chars"
             return EncodingForwarder.GetByteCount(this, chars);
         }
 
@@ -83,7 +81,6 @@ namespace System.Text
         public override int GetBytes(String chars, int charIndex, int charCount,
                                               byte[] bytes, int byteIndex)
         {
-            // NOTE: Will throw ArgumentNull of "s" is chars is null.
             return EncodingForwarder.GetBytes(this, chars, charIndex, charCount, bytes, byteIndex);
         }
 
@@ -149,8 +146,6 @@ namespace System.Text
         [System.Security.SecuritySafeCritical]  // auto-generated
         public override String GetString(byte[] bytes, int byteIndex, int byteCount)
         {
-            // NOTE: If the byteIndex/byteCount parameters are invalid, this will
-            // throw an ArgumentOutOfRange for "index" or "count" instead of those names.
             return EncodingForwarder.GetString(this, bytes, byteIndex, byteCount);
         }
         
diff --git a/src/coreclr/src/mscorlib/src/System/Text/EncodingForwarder.cs b/src/coreclr/src/mscorlib/src/System/Text/EncodingForwarder.cs
index 51c4830..abf21d8 100644
--- a/src/coreclr/src/mscorlib/src/System/Text/EncodingForwarder.cs
+++ b/src/coreclr/src/mscorlib/src/System/Text/EncodingForwarder.cs
@@ -63,7 +63,8 @@ namespace System.Text
             Contract.Assert(encoding != null);
             if (s == null)
             {
-                throw new ArgumentNullException("s");
+                string paramName = encoding is ASCIIEncoding ? "chars" : "s"; // ASCIIEncoding calls the string chars
+                throw new ArgumentNullException(paramName);
             }
             Contract.EndContractBlock();
 
@@ -101,7 +102,8 @@ namespace System.Text
             Contract.Assert(encoding != null);
             if (s == null || bytes == null)
             {
-                throw new ArgumentNullException(s == null ? "s" : "bytes", Environment.GetResourceString("ArgumentNull_Array"));
+                string stringName = encoding is ASCIIEncoding ? "chars" : "s"; // ASCIIEncoding calls the first parameter chars
+                throw new ArgumentNullException(s == null ? stringName : "bytes", Environment.GetResourceString("ArgumentNull_Array"));
             }
             if (charIndex < 0 || charCount < 0)
             {
@@ -109,7 +111,9 @@ namespace System.Text
             }
             if (s.Length - charIndex < charCount)
             {
-                throw new ArgumentOutOfRangeException("s", Environment.GetResourceString("ArgumentOutOfRange_IndexCount"));
+                string stringName = encoding is ASCIIEncoding ? "chars" : "s"; // ASCIIEncoding calls the first parameter chars
+                // Duplicate the above check since we don't want the overhead of a type check on the general path
+                throw new ArgumentOutOfRangeException(stringName, Environment.GetResourceString("ArgumentOutOfRange_IndexCount"));
             }
             if (byteIndex < 0 || byteIndex > bytes.Length)
             {
@@ -293,7 +297,11 @@ namespace System.Text
             }
             if (index < 0 || count < 0)
             {
-                throw new ArgumentOutOfRangeException(index < 0 ? "index" : "count", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
+                // ASCIIEncoding has different names for its parameters here (byteIndex, byteCount)
+                bool ascii = encoding is ASCIIEncoding;
+                string indexName = ascii ? "byteIndex" : "index";
+                string countName = ascii ? "byteCount" : "count";
+                throw new ArgumentOutOfRangeException(index < 0 ? indexName : countName, Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
             }
             if (bytes.Length - index < count)
             {
diff --git a/src/coreclr/src/mscorlib/src/System/Text/UTF8Encoding.cs b/src/coreclr/src/mscorlib/src/System/Text/UTF8Encoding.cs
index e21f1cb..fa6e957 100644
--- a/src/coreclr/src/mscorlib/src/System/Text/UTF8Encoding.cs
+++ b/src/coreclr/src/mscorlib/src/System/Text/UTF8Encoding.cs
@@ -124,8 +124,6 @@ namespace System.Text
         [System.Security.SecuritySafeCritical]  // auto-generated
         public override int GetByteCount(String chars)
         {
-            // NOTE: If chars is null, this will throw an ArgumentNullException
-            // with the parameter name "s" rather than "chars"
             return EncodingForwarder.GetByteCount(this, chars);
         }
 
-- 
2.7.4