Move type to its own file. Add contracts.

src/Features/Core/Portable/AddImport/AddImportFixData.cs

@@ -7,14 +7,6 @@
 
 namespace Microsoft.CodeAnalysis.AddImport
 {
-    internal enum AddImportFixKind
-    {
-        ProjectSymbol,
-        MetadataSymbol,
-        PackageSymbol,
-        ReferenceAssemblySymbol,
-    }
-
     internal class AddImportFixData
     {
         public AddImportFixKind Kind { get; }

src/Features/Core/Portable/AddImport/AddImportFixKind.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.
+
+
+namespace Microsoft.CodeAnalysis.AddImport
+{
+    internal enum AddImportFixKind
+    {
+        ProjectSymbol,
+        MetadataSymbol,
+        PackageSymbol,
+        ReferenceAssemblySymbol,
+    }
+}
\ No newline at end of file

src/Features/Core/Portable/AddImport/CodeActions/AssemblyReferenceCodeAction.cs

@@ -21,6 +21,7 @@ private class AssemblyReferenceCodeAction : AddImportCodeAction
                     AddImportFixData fixData)
                     : base(originalDocument, fixData)
                 {
+                    Contract.ThrowIfFalse(fixData.Kind == AddImportFixKind.ReferenceAssemblySymbol);
                     _lazyResolvedPath = new Lazy<string>(ResolvePath);
                 }
 

src/Features/Core/Portable/AddImport/CodeActions/InstallPackageAndAddImportCodeAction.cs

@@ -8,6 +8,7 @@
 using Microsoft.CodeAnalysis.CodeActions;
 using Microsoft.CodeAnalysis.Shared.Utilities;
 using Microsoft.CodeAnalysis.Text;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.AddImport
 {
@@ -27,6 +28,7 @@ private class InstallPackageAndAddImportCodeAction : AddImportCodeAction
                     InstallPackageDirectlyCodeActionOperation installOperation)
                     : base(originalDocument, fixData, title)
                 {
+                    Contract.ThrowIfFalse(fixData.Kind == AddImportFixKind.PackageSymbol);
                     _installOperation = installOperation;
                 }
 

src/Features/Core/Portable/AddImport/CodeActions/MetadataSymbolReferenceCodeAction.cs

@@ -12,6 +12,7 @@ private class MetadataSymbolReferenceCodeAction : SymbolReferenceCodeAction
             public MetadataSymbolReferenceCodeAction(Document originalDocument, AddImportFixData fixData)
                 : base(originalDocument, fixData)
             {
+                Contract.ThrowIfFalse(fixData.Kind == AddImportFixKind.MetadataSymbol);
             }
 
             protected override Project UpdateProject(Project project)

src/Features/Core/Portable/AddImport/CodeActions/ParentInstallPackageCodeAction.cs

@@ -6,6 +6,7 @@
 using Microsoft.CodeAnalysis.CodeActions;
 using Microsoft.CodeAnalysis.Packaging;
 using Microsoft.CodeAnalysis.Tags;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.AddImport
 {
@@ -37,6 +38,7 @@ private class ParentInstallPackageCodeAction : CodeAction.CodeActionWithNestedAc
                            CreateNestedActions(document, fixData, installerService),
                            isInlinable: false)
                 {
+                    Contract.ThrowIfFalse(fixData.Kind == AddImportFixKind.PackageSymbol);
                 }
 
                 private static ImmutableArray<CodeAction> CreateNestedActions(

src/Features/Core/Portable/AddImport/CodeActions/ProjectSymbolReferenceCodeAction.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 Roslyn.Utilities;
+
 namespace Microsoft.CodeAnalysis.AddImport
 {
     internal abstract partial class AbstractAddImportCodeFixProvider<TSimpleNameSyntax>
@@ -17,6 +19,7 @@ private class ProjectSymbolReferenceCodeAction : SymbolReferenceCodeAction
                 AddImportFixData fixData)
                 : base(originalDocument, fixData)
             {
+                Contract.ThrowIfFalse(fixData.Kind == AddImportFixKind.ProjectSymbol);
             }
 
             private bool ShouldAddProjectReference()

src/Features/Core/Portable/Features.csproj

@@ -100,6 +100,7 @@
       <Link>Shared\Utilities\DesktopShim.cs</Link>
     </Compile>
     <Compile Include="AddImport\AddImportFixData.cs" />
+    <Compile Include="AddImport\AddImportFixKind.cs" />
     <Compile Include="AddImport\CodeActions\AddImportCodeAction.cs" />
     <Compile Include="AddImport\CodeActions\AssemblyReferenceCodeAction.cs" />
     <Compile Include="AddImport\CodeActions\MetadataSymbolReferenceCodeAction.cs" />