Extract DocumentSpanExtensions to its own file

src/Features/Core/Portable/DocumentSpan.cs

@@ -2,9 +2,6 @@
 
 using System;
 using System.Collections.Immutable;
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Navigation;
 using Microsoft.CodeAnalysis.Text;
 using Roslyn.Utilities;
 
@@ -55,36 +52,4 @@ public override int GetHashCode()
                 this.Document,
                 this.SourceSpan.GetHashCode());
     }
-
-    internal static class DocumentSpanExtensions
-    {
-        public static bool CanNavigateTo(this DocumentSpan documentSpan)
-        {
-            var workspace = documentSpan.Document.Project.Solution.Workspace;
-            var service = workspace.Services.GetService<IDocumentNavigationService>();
-            return service.CanNavigateToSpan(workspace, documentSpan.Document.Id, documentSpan.SourceSpan);
-        }
-
-        public static bool TryNavigateTo(this DocumentSpan documentSpan, bool isPreview)
-        {
-            var solution = documentSpan.Document.Project.Solution;
-            var workspace = solution.Workspace;
-            var service = workspace.Services.GetService<IDocumentNavigationService>();
-            return service.TryNavigateToSpan(workspace, documentSpan.Document.Id, documentSpan.SourceSpan,
-                options: solution.Options.WithChangedOption(NavigationOptions.PreferProvisionalTab, isPreview));
-        }
-
-        public static async Task<bool> IsHiddenAsync(
-            this DocumentSpan documentSpan, CancellationToken cancellationToken)
-        {
-            var document = documentSpan.Document;
-            if (document.SupportsSyntaxTree)
-            {
-                var tree = await document.GetSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
-                return tree.IsHiddenPosition(documentSpan.SourceSpan.Start, cancellationToken);
-            }
-
-            return false;
-        }
-    }
 }

src/Features/Core/Portable/DocumentSpanExtensions.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Navigation;
+
+namespace Microsoft.CodeAnalysis
+{
+    internal static class DocumentSpanExtensions
+    {
+        public static bool CanNavigateTo(this DocumentSpan documentSpan)
+        {
+            var workspace = documentSpan.Document.Project.Solution.Workspace;
+            var service = workspace.Services.GetService<IDocumentNavigationService>();
+            return service.CanNavigateToSpan(workspace, documentSpan.Document.Id, documentSpan.SourceSpan);
+        }
+
+        public static bool TryNavigateTo(this DocumentSpan documentSpan, bool isPreview)
+        {
+            var solution = documentSpan.Document.Project.Solution;
+            var workspace = solution.Workspace;
+            var service = workspace.Services.GetService<IDocumentNavigationService>();
+            return service.TryNavigateToSpan(workspace, documentSpan.Document.Id, documentSpan.SourceSpan,
+                options: solution.Options.WithChangedOption(NavigationOptions.PreferProvisionalTab, isPreview));
+        }
+
+        public static async Task<bool> IsHiddenAsync(
+            this DocumentSpan documentSpan, CancellationToken cancellationToken)
+        {
+            var document = documentSpan.Document;
+            if (document.SupportsSyntaxTree)
+            {
+                var tree = await document.GetSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
+                return tree.IsHiddenPosition(documentSpan.SourceSpan.Start, cancellationToken);
+            }
+
+            return false;
+        }
+    }
+}