Do not apply Fix All operations to generated code

src/CodeStyle/Core/CodeFixes/FixAllContextHelper.cs

@@ -74,12 +74,13 @@ public static async Task<ImmutableDictionary<Document, ImmutableArray<Diagnostic
             }
 
             return await GetDocumentDiagnosticsToFixAsync(
-                allDiagnostics, projectsToFix, fixAllContext.CancellationToken).ConfigureAwait(false);
+                allDiagnostics, projectsToFix, isGeneratedCode, fixAllContext.CancellationToken).ConfigureAwait(false);
         }
 
         private static async Task<ImmutableDictionary<Document, ImmutableArray<Diagnostic>>> GetDocumentDiagnosticsToFixAsync(
             ImmutableArray<Diagnostic> diagnostics,
             ImmutableArray<Project> projects,
+            Func<Document, CancellationToken, bool> isGeneratedCode,
             CancellationToken cancellationToken)
         {
             var treeToDocumentMap = await GetTreeToDocumentMapAsync(projects, cancellationToken).ConfigureAwait(false);
@@ -89,8 +90,11 @@ private static async Task<ImmutableDictionary<Document, ImmutableArray<Diagnosti
             {
                 cancellationToken.ThrowIfCancellationRequested();
                 var document = documentAndDiagnostics.Key;
-                var diagnosticsForDocument = documentAndDiagnostics.ToImmutableArray();
-                builder.Add(document, diagnosticsForDocument);
+                if (!isGeneratedCode(document, cancellationToken))
+                {
+                    var diagnosticsForDocument = documentAndDiagnostics.ToImmutableArray();
+                    builder.Add(document, diagnosticsForDocument);
+                }
             }
 
             return builder.ToImmutable();

src/VisualStudio/IntegrationTest/IntegrationTests/CSharp/CSharpCodeActions.cs

@@ -281,6 +281,146 @@ public int Y2
             Assert.Equal(expectedText, VisualStudio.Editor.GetText());
         }
 
+        [CriticalWpfTheory]
+        [InlineData(FixAllScope.Project)]
+        [InlineData(FixAllScope.Solution)]
+        [Trait(Traits.Feature, Traits.Features.CodeActionsFixAllOccurrences)]
+        [WorkItem(33507, "https://github.com/dotnet/roslyn/issues/33507")]
+        public void FixAllOccurrencesIgnoresGeneratedCode(FixAllScope scope)
+        {
+            var markup = @"
+using System;
+using $$System.Threading;
+
+class C
+{
+    public IntPtr X1 { get; set; }
+}";
+            var expectedText = @"
+using System;
+
+class C
+{
+    public IntPtr X1 { get; set; }
+}";
+            var generatedSourceMarkup = @"// <auto-generated/>
+using System;
+using $$System.Threading;
+
+class D
+{
+    public IntPtr X1 { get; set; }
+}";
+            var expectedGeneratedSource = @"// <auto-generated/>
+using System;
+
+class D
+{
+    public IntPtr X1 { get; set; }
+}";
+
+            MarkupTestFile.GetPosition(generatedSourceMarkup, out var generatedSource, out int generatedSourcePosition);
+
+            VisualStudio.SolutionExplorer.AddFile(new ProjectUtils.Project(ProjectName), "D.cs", generatedSource, open: false);
+
+            // Switch to the main document we'll be editing
+            VisualStudio.SolutionExplorer.OpenFile(new ProjectUtils.Project(ProjectName), "Class1.cs");
+
+            // Verify that applying a Fix All operation does not change generated files.
+            // This is a regression test for correctness with respect to the design.
+            SetUpEditor(markup);
+            VisualStudio.WaitForApplicationIdle(CancellationToken.None);
+            VisualStudio.Editor.InvokeCodeActionList();
+            VisualStudio.Editor.Verify.CodeAction(
+                "Remove Unnecessary Usings",
+                applyFix: true,
+                fixAllScope: scope);
+
+            Assert.Equal(expectedText, VisualStudio.Editor.GetText());
+
+            VisualStudio.SolutionExplorer.OpenFile(new ProjectUtils.Project(ProjectName), "D.cs");
+            Assert.Equal(generatedSource, VisualStudio.Editor.GetText());
+
+            // Verify that a Fix All in Document in the generated file still does nothing.
+            // ⚠ This is a statement of the current behavior, and not a claim regarding correctness of the design.
+            // The current behavior is observable; any change to this behavior should be part of an intentional design
+            // change.
+            VisualStudio.Editor.MoveCaret(generatedSourcePosition);
+            VisualStudio.Editor.InvokeCodeActionList();
+            VisualStudio.Editor.Verify.CodeAction(
+                "Remove Unnecessary Usings",
+                applyFix: true,
+                fixAllScope: FixAllScope.Document);
+
+            Assert.Equal(generatedSource, VisualStudio.Editor.GetText());
+
+            // Verify that the code action can still be applied manually from within the generated file.
+            // This is a regression test for correctness with respect to the design.
+            VisualStudio.Editor.MoveCaret(generatedSourcePosition);
+            VisualStudio.Editor.InvokeCodeActionList();
+            VisualStudio.Editor.Verify.CodeAction(
+                "Remove Unnecessary Usings",
+                applyFix: true,
+                fixAllScope: null);
+
+            Assert.Equal(expectedGeneratedSource, VisualStudio.Editor.GetText());
+        }
+
+        [CriticalWpfTheory]
+        [InlineData(FixAllScope.Project)]
+        [InlineData(FixAllScope.Solution)]
+        [Trait(Traits.Feature, Traits.Features.CodeActionsFixAllOccurrences)]
+        [WorkItem(33507, "https://github.com/dotnet/roslyn/issues/33507")]
+        public void FixAllOccurrencesTriggeredFromGeneratedCode(FixAllScope scope)
+        {
+            var markup = @"// <auto-generated/>
+using System;
+using $$System.Threading;
+
+class C
+{
+    public IntPtr X1 { get; set; }
+}";
+            var secondFile = @"
+using System;
+using System.Threading;
+
+class D
+{
+    public IntPtr X1 { get; set; }
+}";
+            var expectedSecondFile = @"
+using System;
+
+class D
+{
+    public IntPtr X1 { get; set; }
+}";
+
+            VisualStudio.SolutionExplorer.AddFile(new ProjectUtils.Project(ProjectName), "D.cs", secondFile, open: false);
+
+            // Switch to the main document we'll be editing
+            VisualStudio.SolutionExplorer.OpenFile(new ProjectUtils.Project(ProjectName), "Class1.cs");
+
+            // Verify that applying a Fix All operation does not change generated file, but does change other files.
+            // ⚠ This is a statement of the current behavior, and not a claim regarding correctness of the design.
+            // The current behavior is observable; any change to this behavior should be part of an intentional design
+            // change.
+            MarkupTestFile.GetPosition(markup, out var expectedText, out int _);
+            SetUpEditor(markup);
+            VisualStudio.WaitForApplicationIdle(CancellationToken.None);
+            VisualStudio.Editor.InvokeCodeActionList();
+            VisualStudio.Editor.Verify.CodeAction(
+                "Remove Unnecessary Usings",
+                applyFix: true,
+                fixAllScope: scope);
+
+            Assert.Equal(expectedText, VisualStudio.Editor.GetText());
+
+            VisualStudio.SolutionExplorer.OpenFile(new ProjectUtils.Project(ProjectName), "D.cs");
+            Assert.Equal(expectedSecondFile, VisualStudio.Editor.GetText());
+        }
+
         [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateMethod)]
         public void ClassificationInPreviewPane()
         {