Move IDE off of SpecializedCollections.Singleton to using collectoin exprs

src/Analyzers/Core/Analyzers/Formatting/FormatterHelper.cs

@@ -30,10 +30,10 @@ internal static IEnumerable<AbstractFormattingRule> GetDefaultFormattingRules(IS
     /// <param name="cancellationToken">An optional cancellation token.</param>
     /// <returns>The formatted tree's root node.</returns>
     public static SyntaxNode Format(SyntaxNode node, ISyntaxFormatting syntaxFormattingService, SyntaxFormattingOptions options, CancellationToken cancellationToken)
-        => Format(node, SpecializedCollections.SingletonEnumerable(node.FullSpan), syntaxFormattingService, options, rules: null, cancellationToken: cancellationToken);
+        => Format(node, [node.FullSpan], syntaxFormattingService, options, rules: null, cancellationToken: cancellationToken);
 
     public static SyntaxNode Format(SyntaxNode node, TextSpan spanToFormat, ISyntaxFormatting syntaxFormattingService, SyntaxFormattingOptions options, CancellationToken cancellationToken)
-        => Format(node, SpecializedCollections.SingletonEnumerable(spanToFormat), syntaxFormattingService, options, rules: null, cancellationToken: cancellationToken);
+        => Format(node, [spanToFormat], syntaxFormattingService, options, rules: null, cancellationToken: cancellationToken);
 
     /// <summary>
     /// Formats the whitespace of a syntax tree.
@@ -63,5 +63,5 @@ internal static IFormattingResult GetFormattingResult(SyntaxNode node, IEnumerab
     /// <param name="cancellationToken">An optional cancellation token.</param>
     /// <returns>The changes necessary to format the tree.</returns>
     public static IList<TextChange> GetFormattedTextChanges(SyntaxNode node, ISyntaxFormatting syntaxFormattingService, SyntaxFormattingOptions options, CancellationToken cancellationToken)
-        => GetFormattedTextChanges(node, SpecializedCollections.SingletonEnumerable(node.FullSpan), syntaxFormattingService, options, rules: null, cancellationToken: cancellationToken);
+        => GetFormattedTextChanges(node, [node.FullSpan], syntaxFormattingService, options, rules: null, cancellationToken: cancellationToken);
 }

src/Analyzers/Core/Analyzers/PopulateSwitch/PopulateSwitchExpressionHelpers.cs

@@ -35,7 +35,7 @@ public static ICollection<ISymbol> GetMissingEnumMembers(ISwitchExpressionOperat
             }
         }
 
-        return SpecializedCollections.EmptyCollection<ISymbol>();
+        return [];
     }
 
     public static bool HasNullSwitchArm(ISwitchExpressionOperation operation)

src/Analyzers/Core/CodeFixes/NamingStyle/NamingStyleCodeFixProvider.cs

@@ -148,10 +148,7 @@ public FixNameCodeAction(
         }
 
         protected override async Task<IEnumerable<CodeActionOperation>> ComputePreviewOperationsAsync(CancellationToken cancellationToken)
-        {
-            return SpecializedCollections.SingletonEnumerable(
-                new ApplyChangesOperation(await _createChangedSolutionAsync(cancellationToken).ConfigureAwait(false)));
-        }
+            => [new ApplyChangesOperation(await _createChangedSolutionAsync(cancellationToken).ConfigureAwait(false))];
 
         protected override async Task<ImmutableArray<CodeActionOperation>> ComputeOperationsAsync(IProgress<CodeAnalysisProgress> progress, CancellationToken cancellationToken)
         {

src/EditorFeatures/CSharp/AutomaticCompletion/AutomaticLineEnderCommandHandler.cs

@@ -105,7 +105,7 @@ protected override IList<TextChange> FormatBasedOnEndToken(ParsedDocument docume
         var formatter = document.LanguageServices.GetRequiredService<ISyntaxFormattingService>();
         return formatter.GetFormattingResult(
             root,
-            SpecializedCollections.SingletonCollection(CommonFormattingHelpers.GetFormattingSpan(root, span.Value)),
+            [CommonFormattingHelpers.GetFormattingSpan(root, span.Value)],
             options,
             rules: null,
             cancellationToken).GetTextChanges(cancellationToken);

src/EditorFeatures/CSharp/AutomaticCompletion/AutomaticLineEnderCommandHandler_Helpers.cs

@@ -390,9 +390,9 @@ private static (SyntaxNode newNode, SyntaxNode oldNode) ModifyObjectCreationExpr
             // =>
             // var l = new Bar() {}; // I am some comments
             var replacementContainerNode = objectCreationNodeContainer.ReplaceSyntax(
-                nodes: SpecializedCollections.SingletonCollection(baseObjectCreationExpressionNode),
+                nodes: [baseObjectCreationExpressionNode],
                 (_, _) => objectCreationNodeWithCorrectInitializer.WithoutTrailingTrivia(),
-                tokens: SpecializedCollections.SingletonCollection(nextToken),
+                tokens: [nextToken],
                 computeReplacementToken: (_, _) =>
                     SyntaxFactory.Token(SyntaxKind.SemicolonToken).WithTrailingTrivia(objectCreationNodeWithCorrectInitializer.GetTrailingTrivia()),
                 trivia: [],

src/EditorFeatures/CSharp/Formatting/CSharpFormattingInteractionService.cs

@@ -92,7 +92,7 @@ public Task<ImmutableArray<TextChange>> GetFormattingChangesAsync(
         var span = textSpan ?? new TextSpan(0, parsedDocument.Root.FullSpan.Length);
         var formattingSpan = CommonFormattingHelpers.GetFormattingSpan(parsedDocument.Root, span);
 
-        return Task.FromResult(Formatter.GetFormattedTextChanges(parsedDocument.Root, SpecializedCollections.SingletonEnumerable(formattingSpan), document.Project.Solution.Services, options, cancellationToken).ToImmutableArray());
+        return Task.FromResult(Formatter.GetFormattedTextChanges(parsedDocument.Root, [formattingSpan], document.Project.Solution.Services, options, cancellationToken).ToImmutableArray());
     }
 
     public Task<ImmutableArray<TextChange>> GetFormattingChangesOnPasteAsync(Document document, ITextBuffer textBuffer, TextSpan textSpan, CancellationToken cancellationToken)

src/EditorFeatures/Core.Wpf/Interactive/InteractiveWindowResetCommand.cs

@@ -51,7 +51,7 @@ public IEnumerable<string> DetailedDescription
             => null;
 
         public IEnumerable<string> Names
-            => SpecializedCollections.SingletonEnumerable(CommandName);
+            => [CommandName];
 
         public string CommandLine
             => "[" + NoConfigParameterName + "] [" + PlatformNames + "]";

src/EditorFeatures/Core.Wpf/NavigableSymbols/NavigableSymbolService.NavigableSymbol.cs

@@ -42,7 +42,7 @@ public NavigableSymbol(
             public SnapshotSpan SymbolSpan { get; }
 
             public IEnumerable<INavigableRelationship> Relationships
-                => SpecializedCollections.SingletonEnumerable(PredefinedNavigableRelationships.Definition);
+                => [PredefinedNavigableRelationships.Definition];
 
             public void Navigate(INavigableRelationship relationship)
             {

src/EditorFeatures/Core.Wpf/Peek/DefinitionPeekableItem.cs

@@ -41,7 +41,7 @@ public DefinitionPeekableItem(
         }
 
         public override IEnumerable<IPeekRelationship> Relationships
-            => SpecializedCollections.SingletonEnumerable(PredefinedPeekRelationships.Definitions);
+            => [PredefinedPeekRelationships.Definitions];
 
         public override IPeekResultSource GetOrCreateResultSource(string relationshipName)
             => new ResultSource(this);

src/EditorFeatures/Core.Wpf/Peek/ExternalFilePeekableItem.cs

@@ -27,9 +27,7 @@ public ExternalFilePeekableItem(
         }
 
         public override IEnumerable<IPeekRelationship> Relationships
-        {
-            get { return SpecializedCollections.SingletonEnumerable(_relationship); }
-        }
+            => [_relationship];
 
         public override IPeekResultSource GetOrCreateResultSource(string relationshipName)
             => new ResultSource(this);

src/EditorFeatures/Core/InlineHints/InlineHintsDataTaggerProvider.cs

@@ -91,7 +91,7 @@ protected override IEnumerable<SnapshotSpan> GetSpansToTag(ITextView? textView,
             return base.GetSpansToTag(textView, subjectBuffer);
         }
 
-        return SpecializedCollections.SingletonEnumerable(visibleSpanOpt.Value);
+        return [visibleSpanOpt.Value];
     }
 
     protected override async Task ProduceTagsAsync(

src/EditorFeatures/Core/InlineRename/InlineRenameSession.cs

@@ -247,7 +247,7 @@ private void InitializeOpenBuffers(SnapshotSpan triggerSpan)
         }
 
         this.UndoManager.CreateInitialState(this.ReplacementText, _triggerView.Selection, new SnapshotSpan(triggerSpan.Snapshot, startingSpan));
-        _openTextBuffers[triggerSpan.Snapshot.TextBuffer].SetReferenceSpans(SpecializedCollections.SingletonEnumerable(startingSpan.ToTextSpan()));
+        _openTextBuffers[triggerSpan.Snapshot.TextBuffer].SetReferenceSpans([startingSpan.ToTextSpan()]);
 
         UpdateReferenceLocationsTask();
 

src/EditorFeatures/Core/RenameTracking/RenameTrackingTaggerProvider.RenameTrackingCodeAction.cs

@@ -81,8 +81,7 @@ protected override async Task<IEnumerable<CodeActionOperation>> ComputePreviewOp
 
             var solutionSet = await _renameTrackingCommitter.RenameSymbolAsync(cancellationToken).ConfigureAwait(false);
 
-            return SpecializedCollections.SingletonEnumerable(
-                (CodeActionOperation)new ApplyChangesOperation(solutionSet.RenamedSolution));
+            return [new ApplyChangesOperation(solutionSet.RenamedSolution)];
         }
 
         private bool TryInitializeRenameTrackingCommitter(CancellationToken cancellationToken)

src/EditorFeatures/Core/Shared/Extensions/ITextSnapshotExtensions.cs

@@ -44,7 +44,7 @@ public static void FormatAndApplyToBuffer(
         var formatter = document.GetRequiredLanguageService<ISyntaxFormattingService>();
 
         var options = textBuffer.GetSyntaxFormattingOptions(editorOptionsService, document.Project.Services, explicitFormat: false);
-        var result = formatter.GetFormattingResult(documentSyntax.Root, SpecializedCollections.SingletonEnumerable(span), options, rules, cancellationToken);
+        var result = formatter.GetFormattingResult(documentSyntax.Root, [span], options, rules, cancellationToken);
         var changes = result.GetTextChanges(cancellationToken);
 
         using (Logger.LogBlock(FunctionId.Formatting_ApplyResultToBuffer, cancellationToken))

src/EditorFeatures/Core/Tagging/AbstractAsynchronousTaggerProvider.TagSource.cs

@@ -390,8 +390,8 @@ private void RaiseTagsChanged(ITextBuffer buffer, DiffResult difference)
                 return;
             }
 
-            OnTagsChangedForBuffer(SpecializedCollections.SingletonCollection(
-                new KeyValuePair<ITextBuffer, DiffResult>(buffer, difference)),
+            OnTagsChangedForBuffer(
+                [new KeyValuePair<ITextBuffer, DiffResult>(buffer, difference)],
                 highPriority: false);
         }
     }

src/EditorFeatures/Core/Tagging/AbstractAsynchronousTaggerProvider.TagSource_ProduceTags.cs

@@ -90,7 +90,7 @@ private void AccumulateTextChanges(TextContentChangedEventArgs contentChanged)
                         var textChangeRange = new TextChangeRange(new TextSpan(c.OldSpan.Start, c.OldSpan.Length), c.NewLength);
                         this.AccumulatedTextChanges = this.AccumulatedTextChanges == null
                             ? textChangeRange
-                            : this.AccumulatedTextChanges.Accumulate(SpecializedCollections.SingletonEnumerable(textChangeRange));
+                            : this.AccumulatedTextChanges.Accumulate([textChangeRange]);
                     }
 
                     break;

src/EditorFeatures/Core/Tagging/AbstractAsynchronousTaggerProvider.cs

@@ -222,7 +222,7 @@ private void StoreTagSource(ITextView? textView, ITextBuffer subjectBuffer, TagS
     protected virtual IEnumerable<SnapshotSpan> GetSpansToTag(ITextView? textView, ITextBuffer subjectBuffer)
     {
         // For a standard tagger, the spans to tag is the span of the entire snapshot.
-        return SpecializedCollections.SingletonEnumerable(subjectBuffer.CurrentSnapshot.GetFullSpan());
+        return [subjectBuffer.CurrentSnapshot.GetFullSpan()];
     }
 
     /// <summary>

src/EditorFeatures/Core/Tagging/AsynchronousViewportTaggerProvider.SingleViewportTaggerProvider.cs

@@ -80,7 +80,7 @@ protected override IEnumerable<SnapshotSpan> GetSpansToTag(ITextView? textView,
 
             // If we're the 'InView' tagger, tag what was visible. 
             if (_viewPortToTag is ViewPortToTag.InView)
-                return SpecializedCollections.SingletonEnumerable(visibleSpan);
+                return [visibleSpan];
 
             // For the above/below tagger, broaden the span to to the requested portion above/below what's visible, then
             // subtract out the visible range.

src/EditorFeatures/DiagnosticsTestUtilities/Diagnostics/AbstractUserDiagnosticTest.cs

@@ -216,7 +216,7 @@ private static FixAllState GetFixAllState(
             if (scope == FixAllScope.Custom)
             {
                 // Bulk fixing diagnostics in selected scope.                    
-                var diagnosticsToFix = ImmutableDictionary.CreateRange(SpecializedCollections.SingletonEnumerable(KeyValuePairUtil.Create(document, diagnostics.ToImmutableArray())));
+                var diagnosticsToFix = ImmutableDictionary.CreateRange([KeyValuePairUtil.Create(document, diagnostics.ToImmutableArray())]);
                 return FixAllState.Create(fixAllProvider, diagnosticsToFix, fixer, equivalenceKey, optionsProvider);
             }
 

src/EditorFeatures/Test/CodeFixes/CodeFixServiceTests.cs

@@ -411,10 +411,7 @@ private static void GetDocumentAndExtensionManager(
         }
 
         private static IEnumerable<Lazy<CodeFixProvider, CodeChangeProviderMetadata>> CreateFixers()
-        {
-            return SpecializedCollections.SingletonEnumerable(
-                new Lazy<CodeFixProvider, CodeChangeProviderMetadata>(() => new MockFixer(), new CodeChangeProviderMetadata("Test", languages: LanguageNames.CSharp)));
-        }
+            => [new Lazy<CodeFixProvider, CodeChangeProviderMetadata>(() => new MockFixer(), new CodeChangeProviderMetadata("Test", languages: LanguageNames.CSharp))];
 
         internal class MockFixer : CodeFixProvider
         {

src/EditorFeatures/Test/MetadataAsSource/AbstractMetadataAsSourceTests.cs

@@ -47,7 +47,7 @@ public virtual Task DisposeAsync()
         internal static async Task GenerateAndVerifySourceAsync(
             string metadataSource, string symbolName, string projectLanguage, string expected, bool signaturesOnly = true, bool includeXmlDocComments = false, string languageVersion = null, string metadataLanguageVersion = null, string metadataCommonReferences = null)
         {
-            using var context = TestContext.Create(projectLanguage, SpecializedCollections.SingletonEnumerable(metadataSource), includeXmlDocComments, languageVersion: languageVersion, metadataLanguageVersion: metadataLanguageVersion, metadataCommonReferences: metadataCommonReferences);
+            using var context = TestContext.Create(projectLanguage, [metadataSource], includeXmlDocComments, languageVersion: languageVersion, metadataLanguageVersion: metadataLanguageVersion, metadataCommonReferences: metadataCommonReferences);
             await context.GenerateAndVerifySourceAsync(symbolName, expected, signaturesOnly: signaturesOnly);
         }
 
@@ -103,7 +103,7 @@ internal static async Task TestSymbolIdMatchesMetadataAsync(string projectLangua
             var metadataSource = @"[assembly: System.Reflection.AssemblyVersion(""2.0.0.0"")] public class C { }";
             var symbolName = "C";
 
-            using var context = TestContext.Create(projectLanguage, SpecializedCollections.SingletonEnumerable(metadataSource));
+            using var context = TestContext.Create(projectLanguage, [metadataSource]);
             var metadataSymbol = await context.ResolveSymbolAsync(symbolName);
             var metadataSymbolId = metadataSymbol.GetSymbolKey();
             var generatedFile = await context.GenerateSourceAsync(symbolName);