Address PR feedback.

Author: teo-tsirpanis

src/libraries/Microsoft.Bcl.Memory/src/Microsoft.Bcl.Memory.csproj

@@ -5,7 +5,7 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <DefineConstants>$(DefineConstants);MICROSOFT_BCL_MEMORY</DefineConstants>
     <IsPackable>true</IsPackable>
-    <PackageDescription>Provides Base64Url, Utf8, Index and Range types support for .NET Framework and .NET Standard.</PackageDescription>
+    <PackageDescription>Provides Base64Url, Utf8, Index, and Range types support for .NET Framework and .NET Standard.</PackageDescription>
   </PropertyGroup>
 
   <!-- DesignTimeBuild requires all the TargetFramework Derived Properties to not be present in the first property group. -->

src/libraries/System.Private.CoreLib/src/System/Text/Rune.cs

@@ -781,7 +781,7 @@ public int EncodeToUtf8(Span<byte> destination)
 
         public override int GetHashCode() => Value;
 
-#if !MICROSOFT_BCL_MEMORY
+#if SYSTEM_PRIVATE_CORELIB
         /// <summary>
         /// Gets the <see cref="Rune"/> which begins at index <paramref name="index"/> in
         /// string <paramref name="input"/>.
@@ -852,7 +852,7 @@ internal static int ReadFirstRuneFromUtf16Buffer(ReadOnlySpan<char> input)
             return (int)returnValue;
         }
 
-#if !MICROSOFT_BCL_MEMORY
+#if SYSTEM_PRIVATE_CORELIB
         // returns a negative number on failure
         private static int ReadRuneFromString(string input, int index)
         {
@@ -1132,7 +1132,7 @@ private static bool TryEncodeToUtf8(Rune value, Span<byte> destination, out int
             return false;
         }
 
-#if !MICROSOFT_BCL_MEMORY
+#if SYSTEM_PRIVATE_CORELIB
         /// <summary>
         /// Attempts to get the <see cref="Rune"/> which begins at index <paramref name="index"/> in
         /// string <paramref name="input"/>.

src/libraries/System.Private.CoreLib/src/System/Text/Unicode/Utf8.cs

@@ -9,15 +9,10 @@
 
 namespace System.Text.Unicode
 {
-#if SYSTEM_PRIVATE_CORELIB || MICROSOFT_BCL_MEMORY
     /// <summary>
-    /// Provides methods for transcoding between UTF-8 and UTF-16.
+    /// Provides static methods that convert chunked data between UTF-8 and UTF-16 encodings.
     /// </summary>
-    public
-#else
-    internal
-#endif
-        static class Utf8
+    public static class Utf8
     {
         /*
          * OperationStatus-based APIs for transcoding of chunked data.

src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Text/Unicode/Utf8Tests.cs

@@ -75,33 +75,17 @@ public static byte[] DecodeHex(ReadOnlySpan<char> inputHex)
             }
             return result;
 
-            static int FromHex(char c)
-            {
-                if (c >= '0' && c <= '9')
-                {
-                    return c - '0';
-                }
-                else if (c >= 'a' && c <= 'f')
-                {
-                    return c - 'a' + 10;
-                }
-                else
-                {
-                    return c - 'A' + 10;
-                }
-            }
+            static int FromHex(char c) =>
+                c >= '0' && c <= '9' ? c - '0' :
+                c >= 'a' && c <= 'f' ? c - 'a' + 10 :
+                c - 'A' + 10;
 #endif
         }
 
         // !! IMPORTANT !!
         // Don't delete this implementation, as we use it as a reference to make sure the framework's
         // transcoding logic is correct.
-#if NET
-        public
-#else
-        private
-#endif
-            static byte[] ToUtf8(Rune rune)
+        private static byte[] ToUtf8(Rune rune)
         {
             Assert.True(Rune.IsValid(rune.Value), $"Rune with value U+{(uint)rune.Value:X4} is not well-formed.");