Add codefix for setup of ref/out methods

This is one of the most annoying scenarios when mocking APIs that have ref/out arguments. Figuring out the callback parameters, setting up the right output values in an untyped collection of some sort, it's terrible. So rather than that, offer a built-in way to generate a delegate that can be used to directly set up and implement the method, with full typed arguments including ref/out annotations, just like you would if you implemented the interface manually (which you likely do when things get complicated because of this issue!). For easier troubleshooting a VSIX project is also provided so you can more easily debug the completion provider. Setting up tests for this will be more complicated than for built-in analyzers, pending further investigation.
moq · kzu · Oct 29, 2020 · Oct 28, 2020 · Oct 29, 2020 · 2591eceb1aaeb195d6ae97f53f29c7cc26aeb68a
commit 2591eceb1aaeb195d6ae97f53f29c7cc26aeb68a
@@ -39,7 +39,9 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "workflows", "workflows", "{
 		.github\workflows\release.yml = .github\workflows\release.yml
 	EndProjectSection
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Moq.CodeAnalysis.UnitTests", "src\Moq.CodeAnalysis.UnitTests\Moq.CodeAnalysis.UnitTests.csproj", "{7EFC63B5-6978-40C9-8FEF-4FEEB4019B4C}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Moq.CodeAnalysis.UnitTests", "src\Moq.CodeAnalysis.UnitTests\Moq.CodeAnalysis.UnitTests.csproj", "{7EFC63B5-6978-40C9-8FEF-4FEEB4019B4C}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Moq.Vsix", "src\Moq.Vsix\Moq.Vsix.csproj", "{EB67F50E-322F-4B22-9B30-EC80AE7CBE88}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -87,6 +89,10 @@ Global
 		{7EFC63B5-6978-40C9-8FEF-4FEEB4019B4C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{7EFC63B5-6978-40C9-8FEF-4FEEB4019B4C}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{7EFC63B5-6978-40C9-8FEF-4FEEB4019B4C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{EB67F50E-322F-4B22-9B30-EC80AE7CBE88}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{EB67F50E-322F-4B22-9B30-EC80AE7CBE88}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{EB67F50E-322F-4B22-9B30-EC80AE7CBE88}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{EB67F50E-322F-4B22-9B30-EC80AE7CBE88}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

@@ -32,6 +32,7 @@
     <RestoreSources>https://pkg.kzu.io/index.json;https://api.nuget.org/v3/index.json;$(RestoreSources)</RestoreSources>
     <RestoreSources Condition="Exists('$(MSBuildThisFileDirectory)..\..\nugetizer\bin\')">$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)..\..\nugetizer\bin'));$(RestoreSources)</RestoreSources>
     <RestoreSources Condition="Exists('$(MSBuildThisFileDirectory)..\..\stunts\bin\')">$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)..\..\stunts\bin'));$(RestoreSources)</RestoreSources>
+    <RestoreSources Condition="Exists('$(MSBuildThisFileDirectory)..\..\ThisAssembly\bin\')">$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)..\..\ThisAssembly\bin'));$(RestoreSources)</RestoreSources>
 
     <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)Moq.snk</AssemblyOriginatorKeyFile>
     <PublicKey>002400000480000094000000060200000024000052534131000400000100010051155fd0ee280be78d81cc979423f1129ec5dd28edce9cd94fd679890639cad54c121ebdb606f8659659cd313d3b3db7fa41e2271158dd602bb0039a142717117fa1f63d93a2d288a1c2f920ec05c4858d344a45d48ebd31c1368ab783596b382b611d8c92f9c1b3d338296aa21b12f3bc9f34de87756100c172c52a24bad2db</PublicKey>

@@ -8,7 +8,8 @@
   <ItemGroup Label="Core">
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="1.0.0" />
     <PackageVersion Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0" />
-    <PackageVersion Include="ThisAssembly" Version="1.0.0-rc" />
+    <PackageVersion Include="ThisAssembly" Version="1.0.0-rc.1" />
+    <PackageVersion Update="ThisAssembly" Version="42.42.42" Condition="Exists('$(MSBuildThisFileDirectory)..\..\ThisAssembly\bin\')" />
     <PackageVersion Include="NuGetizer" Version="0.4.9" />
     <PackageVersion Update="NuGetizer" Version="42.42.42" Condition="Exists('$(MSBuildThisFileDirectory)..\..\nugetizer\bin\')" />
     <PackageVersion Include="Stunts" Version="$(StuntsVersion)" />
@@ -65,6 +66,8 @@
     <PackageVersion Include="Castle.Core" Version="4.4.1" />
     <PackageVersion Include="Superpower" Version="2.3.0" />
     <PackageVersion Include="Ben.Demystifier" Version="0.1.4" />
+
+    <PackageVersion Include="Microsoft.VSSDK.BuildTools" Version="16.7.3069" />
   </ItemGroup>
 
 </Project>
@@ -1,25 +1,25 @@
-using System.Collections.Immutable;
+using System;
+using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CodeActions;
 using Microsoft.CodeAnalysis.CodeFixes;
 using Microsoft.CodeAnalysis.Editing;
+using Microsoft.CodeAnalysis.Simplification;
+using Superpower.Parsers;
 using CS = Microsoft.CodeAnalysis.CSharp.Syntax;
-using VB = Microsoft.CodeAnalysis.VisualBasic.Syntax;
 using CSFactory = Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
+using VB = Microsoft.CodeAnalysis.VisualBasic.Syntax;
 using VBFactory = Microsoft.CodeAnalysis.VisualBasic.SyntaxFactory;
-using Microsoft.CodeAnalysis.Simplification;
-using System;
-using Moq.Properties;
 
 namespace Moq
 {
     /// <summary>
     /// Generates code for custom delegates used for ref/out mocking.
     /// </summary>
-    [ExportCodeFixProvider(LanguageNames.CSharp, LanguageNames.VisualBasic, Name = "CustomDelegate")]
+    [ExportCodeFixProvider(LanguageNames.CSharp, LanguageNames.VisualBasic, Name = nameof(CustomDelegateCodeFix))]
     public class CustomDelegateCodeFix : CodeFixProvider
     {
         /// <inheritdoc />
@@ -36,6 +36,8 @@ public override async Task RegisterCodeFixesAsync(CodeFixContext context)
             var document = context.Document;
             var span = context.Span;
             var root = await document.GetSyntaxRootAsync(context.CancellationToken);
+            if (root == null)
+                return;
 
             var token = root.FindToken(span.Start);
             if (!token.Span.IntersectsWith(span))
@@ -48,7 +50,7 @@ public override async Task RegisterCodeFixesAsync(CodeFixContext context)
             var semantic = await document.GetSemanticModelAsync(context.CancellationToken);
 
             var node = root.FindNode(span);
-            if (node == null)
+            if (node == null || semantic == null)
                 return;
 
             if (node.IsKind(Microsoft.CodeAnalysis.CSharp.SyntaxKind.Argument))
@@ -66,16 +68,16 @@ public override async Task RegisterCodeFixesAsync(CodeFixContext context)
                 return;
 
             var compilation = await document.Project.GetCompilationAsync();
-            var scope = compilation.GetTypeByMetadataName(typeof(SetupScopeAttribute).FullName);
-            if (scope == null)
+            var scope = compilation?.GetTypeByMetadataName(typeof(SetupScopeAttribute).FullName);
+            if (compilation == null || scope == null)
                 return;
 
             // We only generate for [SetupScope] annotated methods. 
             // TODO: should integrate seamlessly with recursive mocks
-            if (!setupSymbol.CandidateSymbols.Any(c => c.GetAttributes().Any(a => a.AttributeClass == scope)))
+            if (!setupSymbol.CandidateSymbols.Any(c => c.GetAttributes().Any(a => SymbolEqualityComparer.Default.Equals(a.AttributeClass, scope))))
                 return;
 
-            IMethodSymbol targetMethod = null;
+            IMethodSymbol? targetMethod = null;
 
             // CS1593 case
             if (node is CS.LambdaExpressionSyntax)
@@ -119,7 +121,7 @@ public override async Task RegisterCodeFixesAsync(CodeFixContext context)
         }
 
         /// <inheritdoc />
-        public sealed override FixAllProvider GetFixAllProvider() => null;
+        public sealed override FixAllProvider? GetFixAllProvider() => null;
 
         class SetupDelegateCodeAction : CodeAction
         {
@@ -134,7 +136,10 @@ public SetupDelegateCodeAction(Document document, SyntaxNode setup, IMethodSymbo
                 this.symbol = symbol;
             }
 
-            public override string Title => Strings.CustomDelegateCodeFix.TitleFormat(symbol.Name);
+            public override string? EquivalenceKey => symbol.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat) + 
+                "(" + string.Join(",", symbol.Parameters.Select(x => x.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat))) + ")";
+
+            public override string Title => ThisAssembly.Strings.CustomDelegateCodeFix.TitleFormat(symbol.Name);
 
             protected override async Task<Document> GetChangedDocumentAsync(CancellationToken cancellationToken)
             {
@@ -160,10 +165,13 @@ protected override async Task<Document> GetChangedDocumentAsync(CancellationToke
                     node = FindSetup(root);
                 }
                 else
-                {                    
+                {
                     var tempDoc = document.WithSyntaxRoot(generator.ReplaceNode(root, @delegate, signature));
                     tempDoc = await Simplifier.ReduceAsync(tempDoc);
                     var tempRoot = await tempDoc.GetSyntaxRootAsync(cancellationToken);
+                    if (tempRoot == null)
+                        return document;
+
                     var className = generator.GetName(@class);
                     var tempClass = tempRoot.DescendantNodes().First(x =>
                         generator.GetDeclarationKind(x) == DeclarationKind.Class &&
@@ -175,14 +183,21 @@ protected override async Task<Document> GetChangedDocumentAsync(CancellationToke
                     {
                         // Generate the delegate name using full Type+Member name.
                         var semantic = await document.GetSemanticModelAsync(cancellationToken);
-                        var mock = semantic.GetSymbolInfo(
-                            setup.IsKind(Microsoft.CodeAnalysis.CSharp.SyntaxKind.InvocationExpression) ?
-                            (SyntaxNode)((setup as CS.InvocationExpressionSyntax)?.Expression as CS.MemberAccessExpressionSyntax)?.Expression :
-                            ((setup as VB.InvocationExpressionSyntax)?.Expression as VB.MemberAccessExpressionSyntax)?.Expression);
-
-                        if (mock.Symbol != null && 
-                            mock.Symbol.Kind == SymbolKind.Local || 
-                            mock.Symbol.Kind == SymbolKind.Field)
+                        if (semantic == null)
+                            return document;
+
+                        SyntaxNode? memberNode = setup.IsKind(Microsoft.CodeAnalysis.CSharp.SyntaxKind.InvocationExpression) ?
+                            ((setup as CS.InvocationExpressionSyntax)?.Expression as CS.MemberAccessExpressionSyntax)?.Expression :
+                            ((setup as VB.InvocationExpressionSyntax)?.Expression as VB.MemberAccessExpressionSyntax)?.Expression;
+
+                        if (memberNode == null)
+                            return document;
+
+                        var mock = semantic.GetSymbolInfo(memberNode);
+
+                        if (mock.Symbol != null &&
+                            (mock.Symbol.Kind == SymbolKind.Local ||
+                             mock.Symbol.Kind == SymbolKind.Field))
                         {
                             var type = mock.Symbol.Kind == SymbolKind.Local ?
                                 ((ILocalSymbol)mock.Symbol).Type :
@@ -200,10 +215,11 @@ protected override async Task<Document> GetChangedDocumentAsync(CancellationToke
                 root = generator.ReplaceNode(root, node, generator.WithTypeArguments(node, generator.IdentifierName(delegateName)));
                 // Find the updated setup
                 node = FindSetup(root);
+                if (node == null || node.Parent == null)
+                    return document;
 
                 // Detect recursive mock access and wrap in a Func<TDelegate>
-                if (
-                    node.Parent.ChildNodes()
+                if (node.Parent.ChildNodes()
                         .OfType<CS.ArgumentListSyntax>()
                         .Where(list => !list.Arguments.Select(arg => arg.Expression).OfType<CS.LambdaExpressionSyntax>().Any())
                         .SelectMany(list => list.DescendantNodes().OfType<CS.MemberAccessExpressionSyntax>())
@@ -226,12 +242,15 @@ protected override async Task<Document> GetChangedDocumentAsync(CancellationToke
                         generator.ValueReturningLambdaExpression(expression));
                     // Find the updated setup
                     node = FindSetup(root);
+                    if (node == null || node.Parent == null)
+                        return document;
                 }
 
                 // If there is no Returns, generate one
-                if (node.Parent.Parent.IsKind(Microsoft.CodeAnalysis.CSharp.SyntaxKind.ExpressionStatement))
+                if (node.Parent?.Parent != null &&
+                    node.Parent.Parent.IsKind(Microsoft.CodeAnalysis.CSharp.SyntaxKind.ExpressionStatement))
                 {
-                    var returns = generator.InvocationExpression(
+                    var returns = (CS.InvocationExpressionSyntax)generator.InvocationExpression(
                         generator.MemberAccessExpression(
                             node.Parent.WithTrailingTrivia(
                                 node.Parent.Parent.GetLeadingTrivia().Add(CSFactory.Whitespace("\t"))),
@@ -242,15 +261,29 @@ protected override async Task<Document> GetChangedDocumentAsync(CancellationToke
 
                     // Replace the parent InvocationExpression with the returning one.
                     root = generator.ReplaceNode(root, node.Parent, returns);
+
+                    // Find the updated setup
+                    node = FindSetup(root);
+
+                    var statement = node.Ancestors().OfType<CS.ExpressionStatementSyntax>().FirstOrDefault();
+                    if (statement != null && 
+                        (statement.GetTrailingTrivia().Count == 0 || 
+                        !statement.GetTrailingTrivia().Any(t => t.Token == statement.SemicolonToken)))
+                    {
+                        root = generator.ReplaceNode(root, statement, statement
+                            .WithSemicolonToken(CSFactory.Token(Microsoft.CodeAnalysis.CSharp.SyntaxKind.SemicolonToken)
+                            .WithTrailingTrivia(statement.GetTrailingTrivia().Insert(0, CSFactory.ElasticCarriageReturnLineFeed))));
+                    }
                 }
-                else if (node.Parent.Parent.IsKind(Microsoft.CodeAnalysis.VisualBasic.SyntaxKind.ExpressionStatement))
+                else if (node.Parent?.Parent != null && 
+                    node.Parent.Parent.IsKind(Microsoft.CodeAnalysis.VisualBasic.SyntaxKind.ExpressionStatement))
                 {
                     var lambda = VBFactory.MultiLineFunctionLambdaExpression(
                         VBFactory.FunctionLambdaHeader().WithParameterList(
                             VBFactory.ParameterList(
                                 VBFactory.SeparatedList(
                                     symbol.Parameters.Select(prm => (VB.ParameterSyntax)generator.ParameterDeclaration(prm))))),
-                        VBFactory.List(new VB.StatementSyntax[] 
+                        VBFactory.List(new VB.StatementSyntax[]
                         {
                             VBFactory.ThrowStatement(
                                 VBFactory.ObjectCreationExpression(