Add RenameHelper

Author: sharwell

AsyncUsageAnalyzers/AsyncUsageAnalyzers/AsyncUsageAnalyzers.csproj

@@ -45,6 +45,7 @@
     <Compile Include="AnalyzerConstants.cs" />
     <Compile Include="AnalyzerExtensions.cs" />
     <Compile Include="GeneratedCodeAnalysisExtensions.cs" />
+    <Compile Include="Helpers\RenameHelper.cs" />
     <Compile Include="NoCodeFixAttribute.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Resources.Designer.cs">

AsyncUsageAnalyzers/AsyncUsageAnalyzers/Helpers/RenameHelper.cs

@@ -0,0 +1,29 @@
+namespace AsyncUsageAnalyzers.Helpers
+{
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.CodeActions;
+    using Microsoft.CodeAnalysis.Rename;
+
+    internal static class RenameHelper
+    {
+        public static async Task<Solution> RenameSymbolAsync(Document document, SyntaxNode root, SyntaxToken declarationToken, string newName, CancellationToken cancellationToken)
+        {
+            var annotatedRoot = root.ReplaceToken(declarationToken, declarationToken.WithAdditionalAnnotations(RenameAnnotation.Create()));
+            var annotatedSolution = document.Project.Solution.WithDocumentSyntaxRoot(document.Id, annotatedRoot);
+            var annotatedDocument = annotatedSolution.GetDocument(document.Id);
+
+            annotatedRoot = await annotatedDocument.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
+            var annotatedToken = annotatedRoot.FindToken(declarationToken.SpanStart);
+
+            var semanticModel = await annotatedDocument.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
+            var symbol = semanticModel?.GetDeclaredSymbol(annotatedToken.Parent, cancellationToken);
+
+            var newSolution = await Renamer.RenameSymbolAsync(annotatedSolution, symbol, newName, null, cancellationToken).ConfigureAwait(false);
+
+            // TODO: return annotatedSolution instead of newSolution if newSolution contains any new errors (for any project)
+            return newSolution;
+        }
+    }
+}