Switch to using index operator

src/EditorFeatures/CSharpTest2/EmbeddedLanguages/RegularExpressions/CSharpRegexParserTests.cs

@@ -344,7 +344,7 @@ private static void CheckCharacters(VirtualCharSequence virtualChars, ref int po
 
         private static string And(params string[] regexes)
         {
-            var conj = $"({regexes[regexes.Length - 1]})";
+            var conj = $"({regexes[^1]})";
             for (var i = regexes.Length - 2; i >= 0; i--)
                 conj = $"(?({regexes[i]}){conj}|[0-[0]])";
 

src/EditorFeatures/Core/IntelliSense/QuickInfo/IntellisenseQuickInfoBuilder.cs

@@ -81,8 +81,8 @@ private static async Task<ContainerElement> BuildInteractiveContentAsync(
 
                     // Stack the first paragraph of the documentation comments with the last line of the description
                     // to avoid vertical padding between the two.
-                    var lastElement = elements[elements.Count - 1];
-                    elements[elements.Count - 1] = new ContainerElement(
+                    var lastElement = elements[^1];
+                    elements[^1] = new ContainerElement(
                         ContainerElementStyle.Stacked,
                         lastElement,
                         element);

src/Features/CSharp/Portable/LineSeparators/CSharpLineSeparatorService.cs

@@ -299,7 +299,7 @@ private static void ProcessNodeList<T>(SyntaxList<T> children, ArrayBuilder<Text
         {
             if (!seenSeparator)
             {
-                var nextToLast = children[children.Count - 2];
+                var nextToLast = children[^2];
                 AddLineSeparatorSpanForNode(nextToLast, spans, cancellationToken);
             }
 

src/Features/Core/Portable/EmbeddedLanguages/RegularExpressions/LanguageServices/RegexBraceMatcher.cs

@@ -80,7 +80,7 @@ public RegexBraceMatcher()
             return null;
 
         var firstChar = trivia.Value.VirtualChars[0];
-        var lastChar = trivia.Value.VirtualChars[trivia.Value.VirtualChars.Length - 1];
+        var lastChar = trivia.Value.VirtualChars[^1];
         return firstChar != '(' || lastChar != ')'
             ? null
             : new BraceMatchingResult(firstChar.Span, lastChar.Span);

src/Scripting/Core/Hosting/ObjectFormatter/CommonObjectFormatter.Visitor.FormattedMember.cs

@@ -48,7 +48,7 @@ public string GetDisplayName()
 
                 public bool HasKeyName()
                 {
-                    return Index >= 0 && Name != null && Name.Length >= 2 && Name[0] == '[' && Name[Name.Length - 1] == ']';
+                    return Index >= 0 && Name != null && Name.Length >= 2 && Name[0] == '[' && Name[^1] == ']';
                 }
 
                 public bool AppendAsCollectionEntry(Builder result)

src/Scripting/Core/Hosting/ObjectFormatter/CommonObjectFormatter.Visitor.cs

@@ -697,7 +697,7 @@ private void FormatMultidimensionalArrayElements(Builder result, Array array, bo
                     string _;
                     FormatObjectRecursive(result, array.GetValue(indices), isRoot: false, debuggerDisplayName: out _);
 
-                    indices[indices.Length - 1]++;
+                    indices[^1]++;
                     flatIndex++;
                 }
             }

src/VisualStudio/Core/Def/Library/VsNavInfo/NavInfo.cs

@@ -59,7 +59,7 @@ public NavInfo(
         _basePresentationNodes = CreateNodes(expandDottedNames: false);
 
         _symbolType = _basePresentationNodes.Length > 0
-            ? _basePresentationNodes[_basePresentationNodes.Length - 1].ListType
+            ? _basePresentationNodes[^1].ListType
             : 0;
     }
 

src/VisualStudio/Core/Def/Preview/FileChange.cs

@@ -135,7 +135,7 @@ private static string GetDisplayText(string excerpt)
             var split = excerpt.Split(new[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
             if (split.Length > 1)
             {
-                return string.Format("{0} ... {1}", split[0].Trim(), split[split.Length - 1].Trim());
+                return string.Format("{0} ... {1}", split[0].Trim(), split[^1].Trim());
             }
         }
 

src/VisualStudio/Core/Def/ValueTracking/ValueTrackingTree.xaml.cs

@@ -114,7 +114,7 @@ private TreeViewItemBase GetPreviousItem()
     {
         if (ValueTrackingTreeView.SelectedItem is null)
         {
-            return (TreeViewItemBase)ValueTrackingTreeView.Items[ValueTrackingTreeView.Items.Count - 1];
+            return (TreeViewItemBase)ValueTrackingTreeView.Items[^1];
         }
 
         var item = (TreeViewItemBase)ValueTrackingTreeView.SelectedItem;

src/VisualStudio/Core/Def/Venus/ContainedDocument.cs

@@ -1073,7 +1073,7 @@ private bool IsCodeBlock(ITextSnapshot surfaceSnapshot, int position, char ch)
 
     private static bool CheckCode(ITextSnapshot snapshot, int position, char ch, string tag, bool checkAt = true)
     {
-        if (ch != tag[tag.Length - 1] || position < tag.Length)
+        if (ch != tag[^1] || position < tag.Length)
         {
             return false;
         }

src/VisualStudio/Core/Impl/CodeModel/AbstractCodeModelService.AbstractNodeNameGenerator.cs

@@ -23,7 +23,7 @@ protected abstract class AbstractNodeNameGenerator
             protected static void AppendDotIfNeeded(StringBuilder builder)
             {
                 if (builder.Length > 0 &&
-                    char.IsLetterOrDigit(builder[builder.Length - 1]))
+                    char.IsLetterOrDigit(builder[^1]))
                 {
                     builder.Append('.');
                 }

src/VisualStudio/LiveShare/Impl/Client/RemoteLanguageServiceWorkspace.cs

@@ -175,7 +175,7 @@ private async Task UpdatePathsToRemoteFilesAsync(CollaborationSession session)
 #pragma warning disable CS8602 // Dereference of a possibly null reference. (Can localRoot be null here?)
                 var splitRoot = localRoot.TrimEnd('\\').Split('\\');
 #pragma warning restore CS8602 // Dereference of a possibly null reference.
-                splitRoot[splitRoot.Length - 1] = "~external";
+                splitRoot[^1] = "~external";
                 var externalPath = string.Join("\\", splitRoot) + "\\";
 
                 remoteRootPaths.Add(localRoot);

src/Workspaces/MSBuildTest/MSBuildWorkspaceTestBase.cs

@@ -101,11 +101,11 @@ protected static int GetMethodInsertionPoint(VB.Syntax.ClassBlockSyntax classBlo
         {
             if (classBlock.Implements.Count > 0)
             {
-                return classBlock.Implements[classBlock.Implements.Count - 1].FullSpan.End;
+                return classBlock.Implements[^1].FullSpan.End;
             }
             else if (classBlock.Inherits.Count > 0)
             {
-                return classBlock.Inherits[classBlock.Inherits.Count - 1].FullSpan.End;
+                return classBlock.Inherits[^1].FullSpan.End;
             }
             else
             {

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Services/SyntaxFacts/AbstractDocumentationCommentService.cs

@@ -185,7 +185,7 @@ private static bool HasLeadingWhitespace(string tokenText)
         => tokenText.Length > 0 && char.IsWhiteSpace(tokenText[0]);
 
     private static bool HasTrailingWhitespace(string tokenText)
-        => tokenText.Length > 0 && char.IsWhiteSpace(tokenText[tokenText.Length - 1]);
+        => tokenText.Length > 0 && char.IsWhiteSpace(tokenText[^1]);
 
     public string GetBannerText(SyntaxNode documentationCommentTriviaSyntax, int maxBannerLength, CancellationToken cancellationToken)
         => GetBannerText((TDocumentationCommentTriviaSyntax)documentationCommentTriviaSyntax, maxBannerLength, cancellationToken);

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/SymbolKey/SymbolKey.SymbolKeyWriter.cs

@@ -516,7 +516,7 @@ public void PushMethod(IMethodSymbol method)
         public void PopMethod(IMethodSymbol method)
         {
             Contract.ThrowIfTrue(_methodSymbolStack.Count == 0);
-            Contract.ThrowIfFalse(method.Equals(_methodSymbolStack[_methodSymbolStack.Count - 1]));
+            Contract.ThrowIfFalse(method.Equals(_methodSymbolStack[^1]));
             _methodSymbolStack.RemoveAt(_methodSymbolStack.Count - 1);
         }
     }

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Utilities/EditDistance.cs

@@ -178,7 +178,7 @@ private static int GetEditDistanceWorker(ReadOnlySpan<char> source, ReadOnlySpan
         // First:
         // Determine the common prefix/suffix portions of the strings.  We don't even need to 
         // consider them as they won't add anything to the edit cost.
-        while (source.Length > 0 && source[source.Length - 1] == target[target.Length - 1])
+        while (source.Length > 0 && source[^1] == target[^1])
         {
             source = source[..^1];
             target = target[..^1];

src/Workspaces/SharedUtilitiesAndExtensions/Workspace/CSharp/CodeGeneration/EnumMemberGenerator.cs

@@ -39,7 +39,7 @@ internal static EnumDeclarationSyntax AddEnumMemberTo(EnumDeclarationSyntax dest
         {
             var lastMember = members.Last();
             var trailingTrivia = lastMember.GetTrailingTrivia();
-            members[members.Count - 1] = lastMember.WithTrailingTrivia();
+            members[^1] = lastMember.WithTrailingTrivia();
             members.Add(SyntaxFactory.Token(SyntaxKind.CommaToken).WithTrailingTrivia(trailingTrivia));
             members.Add(member);
         }