Treat unused private field as errors (and fix)

Author: andyleejordan

.editorconfig

@@ -25,6 +25,8 @@ dotnet_diagnostic.CS0414.severity = error
 dotnet_diagnostic.CA2007.severity = error
 # CA1822: Mark members as static
 dotnet_diagnostic.CA1822.severity = error
+# CA1823: Avoid unused private fields
+dotnet_diagnostic.CA1823.severity = error
 # All maintainability issues (dead code etc.)
 # See: https://docs.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/maintainability-warnings
 dotnet_analyzer_diagnostic.category-Maintainability.severity = error

src/PowerShellEditorServices/Services/TextDocument/TokenOperations.cs

@@ -14,9 +14,6 @@ namespace Microsoft.PowerShell.EditorServices.Services.TextDocument
     /// </summary>
     internal static class TokenOperations
     {
-        // Region kinds to align with VSCode's region kinds
-        private const string RegionKindComment = "comment";
-        private const string RegionKindRegion = "region";
         private static readonly FoldingRangeKind? RegionKindNone = null;
 
         // These regular expressions are used to match lines which mark the start and end of region comment in a PowerShell

test/PowerShellEditorServices.Test.Shared/TestUtilities/TestUtilities.cs

@@ -14,8 +14,6 @@ namespace Microsoft.PowerShell.EditorServices.Test.Shared
     /// </summary>
     public static class TestUtilities
     {
-        private static readonly char[] s_unixPathSeparators = new [] { '/' };
-
         private static readonly char[] s_unixNewlines = new [] { '\n' };
 
         /// <summary>

test/PowerShellEditorServices.Test/Session/WorkspaceTests.cs

@@ -14,8 +14,6 @@ namespace Microsoft.PowerShell.EditorServices.Test.Session
 {
     public class WorkspaceTests
     {
-        private static readonly Version PowerShellVersion = new Version("5.0");
-
         private static readonly Lazy<string> s_lazyDriveLetter = new Lazy<string>(() => Path.GetFullPath("\\").Substring(0, 1));
 
         public static string CurrentDriveLetter => RuntimeInformation.IsOSPlatform(OSPlatform.Windows)