Replace polyfills with PolyShim

CliFx.Analyzers/CliFx.Analyzers.csproj

@@ -6,7 +6,7 @@
     <GenerateDependencyFile>true</GenerateDependencyFile>
     <NoWarn>$(NoWarn);RS1025;RS1026</NoWarn>
   </PropertyGroup>
-  
+
   <PropertyGroup>
     <!--
       Because this project only has a single target framework, the condition in
@@ -17,6 +17,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.5.0" PrivateAssets="all" />
+    <PackageReference Include="PolyShim" Version="1.0.0" PrivateAssets="all" />
   </ItemGroup>
 
 </Project>

CliFx/CliFx.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
     <IsPackable>true</IsPackable>
   </PropertyGroup>
 
@@ -27,11 +27,8 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="all" />
-    <PackageReference Include="PolySharp" Version="1.12.1" PrivateAssets="all" />
+    <PackageReference Include="PolyShim" Version="1.0.0" PrivateAssets="all" />
-  </ItemGroup>
+    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.4" Condition="'$(TargetFramework)' == 'netstandard2.0'" />
-
-  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
-    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.4" />
   </ItemGroup>
 
   <!-- Embed the analyzer inside the package -->

CliFx/Utils/Polyfills.Collections.cs

@@ -1,26 +0,0 @@
-// ReSharper disable CheckNamespace
-
-#if NETSTANDARD2_0
-using System.Collections.Generic;
-
-internal static class CollectionPolyfills
-{
-    public static void Deconstruct<TKey, TValue>(this KeyValuePair<TKey, TValue> pair, out TKey key, out TValue value)
-    {
-        key = pair.Key;
-        value = pair.Value;
-    }
-
-    public static TValue GetValueOrDefault<TKey, TValue>(this IReadOnlyDictionary<TKey, TValue> dic, TKey key) =>
-        dic.TryGetValue(key!, out var result) ? result! : default!;
-}
-
-namespace System.Linq
-{
-    internal static class LinqPolyfills
-    {
-        public static HashSet<T> ToHashSet<T>(this IEnumerable<T> source, IEqualityComparer<T> comparer) =>
-            new(source, comparer);
-    }
-}
-#endif

CliFx/Utils/Polyfills.Regex.cs

@@ -1,12 +0,0 @@
-// ReSharper disable CheckNamespace
-
-#if NETSTANDARD2_0
-using System.Linq;
-using System.Text.RegularExpressions;
-
-internal static class RegexPolyfills
-{
-    public static Match[] ToArray(this MatchCollection matches) =>
-        matches.Cast<Match>().ToArray();
-}
-#endif

CliFx/Utils/Polyfills.Streams.cs

@@ -1,11 +0,0 @@
-// ReSharper disable CheckNamespace
-
-#if NETSTANDARD2_0
-using System.IO;
-
-internal static class StreamPolyfills
-{
-    public static void Write(this Stream stream, byte[] buffer) =>
-        stream.Write(buffer, 0, buffer.Length);
-}
-#endif

CliFx/Utils/Polyfills.Strings.cs

@@ -1,12 +0,0 @@
-// ReSharper disable CheckNamespace
-
-#if NETSTANDARD2_0
-internal static class StringPolyfills
-{
-    public static bool StartsWith(this string str, char c) =>
-        str.Length > 0 && str[0] == c;
-
-    public static bool EndsWith(this string str, char c) =>
-        str.Length > 0 && str[^1] == c;
-}
-#endif