Merge pull request #1216 from sharwell/multi-target

Support Roslyn 3.8 and Roslyn 4.0 source generator scenarios

InterfaceStubGenerator.Roslyn38/InterfaceStubGenerator.Roslyn38.csproj

@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0</TargetFrameworks>
+    <AssemblyName>InterfaceStubGeneratorV1</AssemblyName>
     <RootNamespace>Refit.Generator</RootNamespace>
     <IsPackable>false</IsPackable>
     <AssemblyOriginatorKeyFile>..\buildtask.snk</AssemblyOriginatorKeyFile>
@@ -21,4 +22,6 @@
     </PropertyGroup>
   </Target>
 
+  <Import Project="..\InterfaceStubGenerator.Shared\InterfaceStubGenerator.Shared.projitems" Label="Shared" />
+
 </Project>

InterfaceStubGenerator.Roslyn40/InterfaceStubGenerator.Roslyn40.csproj

@@ -0,0 +1,28 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>netstandard2.0</TargetFrameworks>
+    <AssemblyName>InterfaceStubGeneratorV2</AssemblyName>
+    <RootNamespace>Refit.Generator</RootNamespace>
+    <IsPackable>false</IsPackable>
+    <AssemblyOriginatorKeyFile>..\buildtask.snk</AssemblyOriginatorKeyFile>
+    <SignAssembly>true</SignAssembly>
+    <IsRoslynComponent>true</IsRoslynComponent>
+    <Nullable>enable</Nullable>
+    <DefineConstants>$(DefineConstants);ROSLYN_4</DefineConstants>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.0.0-2.final" PrivateAssets="all" />
+  </ItemGroup>
+
+  <Target Name="SetBuildVer" AfterTargets="GetBuildVersion" BeforeTargets="SetCloudBuildVersionVars;SetCloudBuildNumberWithVersion">
+    <PropertyGroup>
+      <Version>$(BuildVersion)</Version>
+      <AssemblyVersion>$(BuildVersionSimple)</AssemblyVersion>
+    </PropertyGroup>
+  </Target>
+
+  <Import Project="..\InterfaceStubGenerator.Shared\InterfaceStubGenerator.Shared.projitems" Label="Shared" />
+
+</Project>

InterfaceStubGenerator.Shared/InterfaceStubGenerator.Shared.projitems

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <MSBuildAllProjects Condition="'$(MSBuildVersion)' == '' Or '$(MSBuildVersion)' &lt; '16.0'">$(MSBuildAllProjects);$(MSBuildThisFileFullPath)</MSBuildAllProjects>
+    <HasSharedItems>true</HasSharedItems>
+    <SharedGUID>b591423d-f92d-4e00-b0eb-615c9853506c</SharedGUID>
+  </PropertyGroup>
+  <PropertyGroup Label="Configuration">
+    <Import_RootNamespace>InterfaceStubGenerator.Shared</Import_RootNamespace>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildThisFileDirectory)InterfaceStubGenerator.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)ITypeSymbolExtensions.cs" />
+  </ItemGroup>
+</Project>

InterfaceStubGenerator.Shared/InterfaceStubGenerator.Shared.shproj

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>b591423d-f92d-4e00-b0eb-615c9853506c</ProjectGuid>
+    <MinimumVisualStudioVersion>14.0</MinimumVisualStudioVersion>
+  </PropertyGroup>
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.Default.props" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.props" />
+  <PropertyGroup />
+  <Import Project="InterfaceStubGenerator.Shared.projitems" Label="Shared" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.CSharp.targets" />
+</Project>

InterfaceStubGenerator.Shared/InterfaceStubGenerator.cs

@@ -17,13 +17,17 @@ namespace Refit.Generator
     //   defn's
 
     [Generator]
+#if ROSLYN_4
+    public class InterfaceStubGeneratorV2 : IIncrementalGenerator
+#else
     public class InterfaceStubGenerator : ISourceGenerator
+#endif
     {
 #pragma warning disable RS2008 // Enable analyzer release tracking
         static readonly DiagnosticDescriptor InvalidRefitMember = new(
                 "RF001",
                 "Refit types must have Refit HTTP method attributes",
-                "Method {0}.{1} either has no Refit HTTP method attribute or you've used something other than a string literal for the 'path' argument.",
+                "Method {0}.{1} either has no Refit HTTP method attribute or you've used something other than a string literal for the 'path' argument",
                 "Refit",
                 DiagnosticSeverity.Warning,
                 true);
@@ -37,40 +41,59 @@ namespace Refit.Generator
                 true);
 #pragma warning restore RS2008 // Enable analyzer release tracking
 
-        public void Execute(GeneratorExecutionContext context)
-        {
-            GenerateInterfaceStubs(context);            
-        }      
+#if !ROSLYN_4
 
-        public void GenerateInterfaceStubs(GeneratorExecutionContext context)
+        public void Execute(GeneratorExecutionContext context)
         {
             if (context.SyntaxReceiver is not SyntaxReceiver receiver)
                 return;
 
             context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.RefitInternalNamespace", out var refitInternalNamespace);
 
+            GenerateInterfaceStubs(
+                context,
+                static (context, diagnostic) => context.ReportDiagnostic(diagnostic),
+                static (context, hintName, sourceText) => context.AddSource(hintName, sourceText),
+                (CSharpCompilation)context.Compilation,
+                refitInternalNamespace,
+                receiver.CandidateMethods.ToImmutableArray(),
+                receiver.CandidateInterfaces.ToImmutableArray());
+        }
+
+#endif
+
+        public void GenerateInterfaceStubs<TContext>(
+            TContext context,
+            Action<TContext, Diagnostic> reportDiagnostic,
+            Action<TContext, string, SourceText> addSource,
+            CSharpCompilation compilation,
+            string? refitInternalNamespace,
+            ImmutableArray<MethodDeclarationSyntax> candidateMethods,
+            ImmutableArray<InterfaceDeclarationSyntax> candidateInterfaces)
+        {
             refitInternalNamespace = $"{refitInternalNamespace ?? string.Empty}RefitInternalGenerated";
 
             // we're going to create a new compilation that contains the attribute.
             // TODO: we should allow source generators to provide source during initialize, so that this step isn't required.
-            var options = (context.Compilation as CSharpCompilation)!.SyntaxTrees[0].Options as CSharpParseOptions;
-            var compilation = context.Compilation;
+            var options = (CSharpParseOptions)compilation.SyntaxTrees[0].Options;
 
             var disposableInterfaceSymbol = compilation.GetTypeByMetadataName("System.IDisposable")!;
             var httpMethodBaseAttributeSymbol = compilation.GetTypeByMetadataName("Refit.HttpMethodAttribute");
 
             if(httpMethodBaseAttributeSymbol == null)
             {
-                context.ReportDiagnostic(Diagnostic.Create(RefitNotReferenced, null));
+                reportDiagnostic(context, Diagnostic.Create(RefitNotReferenced, null));
                 return;
             }
 
 
             // Check the candidates and keep the ones we're actually interested in
 
-            var interfaceToNullableEnabledMap = new Dictionary<INamedTypeSymbol, bool>();
+#pragma warning disable RS1024 // Compare symbols correctly
+            var interfaceToNullableEnabledMap = new Dictionary<INamedTypeSymbol, bool>(SymbolEqualityComparer.Default);
+#pragma warning restore RS1024 // Compare symbols correctly
             var methodSymbols = new List<IMethodSymbol>();
-            foreach (var group in receiver.CandidateMethods.GroupBy(m => m.SyntaxTree))
+            foreach (var group in candidateMethods.GroupBy(m => m.SyntaxTree))
             {
                 var model = compilation.GetSemanticModel(group.Key);             
                 foreach (var method in group)
@@ -79,7 +102,7 @@ namespace Refit.Generator
                     var methodSymbol = model.GetDeclaredSymbol(method);
                     if (IsRefitMethod(methodSymbol, httpMethodBaseAttributeSymbol))
                     {
-                        var isAnnotated = context.Compilation.Options.NullableContextOptions == NullableContextOptions.Enable ||
+                        var isAnnotated = compilation.Options.NullableContextOptions == NullableContextOptions.Enable ||
                             model.GetNullableContext(method.SpanStart) == NullableContext.Enabled;
                         interfaceToNullableEnabledMap[methodSymbol!.ContainingType] = isAnnotated;
 
@@ -88,12 +111,12 @@ namespace Refit.Generator
                 }
             }
 
-            var interfaces = methodSymbols.GroupBy(m => m.ContainingType)
+            var interfaces = methodSymbols.GroupBy<IMethodSymbol, INamedTypeSymbol>(m => m.ContainingType, SymbolEqualityComparer.Default)
                                           .ToDictionary(g => g.Key, v => v.ToList());
 
             // Look through the candidate interfaces
             var interfaceSymbols = new List<INamedTypeSymbol>();
-            foreach(var group in receiver.CandidateInterfaces.GroupBy(i => i.SyntaxTree))
+            foreach(var group in candidateInterfaces.GroupBy(i => i.SyntaxTree))
             {
                 var model = compilation.GetSemanticModel(group.Key);
                 foreach (var iface in group)
@@ -127,7 +150,7 @@ namespace Refit.Generator
             if(!interfaces.Any()) return;
            
 
-            var supportsNullable = ((CSharpParseOptions)context.ParseOptions).LanguageVersion >= LanguageVersion.CSharp8;
+            var supportsNullable = options.LanguageVersion >= LanguageVersion.CSharp8;
 
             var keyCount = new Dictionary<string, int>();
 
@@ -152,10 +175,10 @@ namespace {refitInternalNamespace}
 ";
 
 
-            compilation = context.Compilation.AddSyntaxTrees(CSharpSyntaxTree.ParseText(SourceText.From(attributeText, Encoding.UTF8), options));
+            compilation = compilation.AddSyntaxTrees(CSharpSyntaxTree.ParseText(SourceText.From(attributeText, Encoding.UTF8), options));
 
             // add the attribute text
-            context.AddSource("PreserveAttribute.g.cs", SourceText.From(attributeText, Encoding.UTF8));
+            addSource(context, "PreserveAttribute.g.cs", SourceText.From(attributeText, Encoding.UTF8));
 
             // get the newly bound attribute
             var preserveAttributeSymbol = compilation.GetTypeByMetadataName($"{refitInternalNamespace}.PreserveAttribute")!;
@@ -177,7 +200,7 @@ namespace Refit.Implementation
 }}
 #pragma warning restore
 ";
-            context.AddSource("Generated.g.cs", SourceText.From(generatedClassText, Encoding.UTF8));
+            addSource(context, "Generated.g.cs", SourceText.From(generatedClassText, Encoding.UTF8));
 
             compilation = compilation.AddSyntaxTrees(CSharpSyntaxTree.ParseText(SourceText.From(generatedClassText, Encoding.UTF8), options));
 
@@ -190,14 +213,15 @@ namespace Refit.Implementation
                 // with a refit attribute on them. Types may contain other members, without the attribute, which we'll
                 // need to check for and error out on
 
-                var classSource = ProcessInterface(group.Key,
+                var classSource = ProcessInterface(context,
+                                                   reportDiagnostic,
+                                                   group.Key,
                                                    group.Value,
                                                    preserveAttributeSymbol,
                                                    disposableInterfaceSymbol,
                                                    httpMethodBaseAttributeSymbol,
                                                    supportsNullable,
-                                                   interfaceToNullableEnabledMap[group.Key],
-                                                   context);
+                                                   interfaceToNullableEnabledMap[group.Key]);
              
                 var keyName = group.Key.Name;
                 if(keyCount.TryGetValue(keyName, out var value))
@@ -206,19 +230,20 @@ namespace Refit.Implementation
                 }
                 keyCount[keyName] = value;
 
-                context.AddSource($"{keyName}.g.cs", SourceText.From(classSource, Encoding.UTF8));
+                addSource(context, $"{keyName}.g.cs", SourceText.From(classSource, Encoding.UTF8));
             }           
 
         }
 
-        string ProcessInterface(INamedTypeSymbol interfaceSymbol,
+        string ProcessInterface<TContext>(TContext context,
+                                Action<TContext, Diagnostic> reportDiagnostic,
+                                INamedTypeSymbol interfaceSymbol,
                                 List<IMethodSymbol> refitMethods,
                                 ISymbol preserveAttributeSymbol,
                                 ISymbol disposableInterfaceSymbol,
                                 INamedTypeSymbol httpMethodBaseAttributeSymbol,
                                 bool supportsNullable,
-                                bool nullableEnabled,
-                                GeneratorExecutionContext context)
+                                bool nullableEnabled)
         {
 
             // Get the class name with the type parameters, then remove the namespace
@@ -331,7 +356,7 @@ namespace Refit.Implementation
                     !method.IsAbstract) // If an interface method has a body, it won't be abstract
                     continue;
 
-                ProcessNonRefitMethod(source, method, context);
+                ProcessNonRefitMethod(context, reportDiagnostic, source, method);
             }
 
             // Handle Dispose
@@ -458,7 +483,7 @@ namespace Refit.Implementation
 
         }
 
-        void ProcessNonRefitMethod(StringBuilder source, IMethodSymbol methodSymbol, GeneratorExecutionContext context)
+        void ProcessNonRefitMethod<TContext>(TContext context, Action<TContext, Diagnostic> reportDiagnostic, StringBuilder source, IMethodSymbol methodSymbol)
         {
             WriteMethodOpening(source, methodSymbol, true);
 
@@ -471,7 +496,7 @@ namespace Refit.Implementation
             foreach(var location in methodSymbol.Locations)
             {
                 var diagnostic = Diagnostic.Create(InvalidRefitMember, location, methodSymbol.ContainingType.Name, methodSymbol.Name);
-                context.ReportDiagnostic(diagnostic);
+                reportDiagnostic(context, diagnostic);
             }            
         }
 
@@ -515,6 +540,48 @@ namespace Refit.Implementation
             return methodSymbol?.GetAttributes().Any(ad => ad.AttributeClass?.InheritsFromOrEquals(httpMethodAttibute) == true) == true;
         }
 
+#if ROSLYN_4
+
+        public void Initialize(IncrementalGeneratorInitializationContext context)
+        {
+            // We're looking for methods with an attribute that are in an interface
+            var candidateMethodsProvider = context.SyntaxProvider.CreateSyntaxProvider(
+                (syntax, cancellationToken) => syntax is MethodDeclarationSyntax { Parent: InterfaceDeclarationSyntax, AttributeLists: { Count: > 0 } },
+                (context, cancellationToken) => (MethodDeclarationSyntax)context.Node);
+
+            // We also look for interfaces that derive from others, so we can see if any base methods contain
+            // Refit methods
+            var candidateInterfacesProvider = context.SyntaxProvider.CreateSyntaxProvider(
+                (syntax, cancellationToken) => syntax is InterfaceDeclarationSyntax { BaseList: not null },
+                (context, cancellationToken) => (InterfaceDeclarationSyntax)context.Node);
+
+            var refitInternalNamespace = context.AnalyzerConfigOptionsProvider.Select(
+                (analyzerConfigOptionsProvider, cancellationToken) => analyzerConfigOptionsProvider.GlobalOptions.TryGetValue("build_property.RefitInternalNamespace", out var refitInternalNamespace) ? refitInternalNamespace : null);
+
+            var inputs = candidateMethodsProvider.Collect()
+                .Combine(candidateInterfacesProvider.Collect())
+                .Select((combined, cancellationToken) => (candidateMethods: combined.Left, candidateInterfaces: combined.Right))
+                .Combine(refitInternalNamespace)
+                .Combine(context.CompilationProvider)
+                .Select((combined, cancellationToken) => (combined.Left.Left.candidateMethods, combined.Left.Left.candidateInterfaces, refitInternalNamespace: combined.Left.Right, compilation: combined.Right));
+
+            context.RegisterSourceOutput(
+                inputs,
+                (context, collectedValues) =>
+                {
+                    GenerateInterfaceStubs(
+                        context,
+                        static (context, diagnostic) => context.ReportDiagnostic(diagnostic),
+                        static (context, hintName, sourceText) => context.AddSource(hintName, sourceText),
+                        (CSharpCompilation)collectedValues.compilation,
+                        collectedValues.refitInternalNamespace,
+                        collectedValues.candidateMethods,
+                        collectedValues.candidateInterfaces);
+                });
+        }
+
+#else
+
         public void Initialize(GeneratorInitializationContext context)
         {
             context.RegisterForSyntaxNotifications(() => new SyntaxReceiver());
@@ -544,5 +611,7 @@ namespace Refit.Implementation
                 }
             }
         }
+
+#endif
     }
 }

Refit.Tests/InterfaceStubGenerator.cs

@@ -16,6 +16,7 @@ using Xunit;
 
 using Task = System.Threading.Tasks.Task;
 using VerifyCS = Refit.Tests.CSharpSourceGeneratorVerifier<Refit.Generator.InterfaceStubGenerator>;
+using VerifyCSV2 = Refit.Tests.CSharpIncrementalSourceGeneratorVerifier<Refit.Generator.InterfaceStubGeneratorV2>;
 
 namespace Refit.Tests
 {
@@ -102,6 +103,7 @@ namespace Refit.Tests
         public async Task NoRefitInterfacesSmokeTest()
         {
             var input = File.ReadAllText(IntegrationTestHelper.GetPath("IInterfaceWithoutRefit.cs"));
+
             await new VerifyCS.Test
             {
                 ReferenceAssemblies = ReferenceAssemblies,
@@ -111,6 +113,16 @@ namespace Refit.Tests
                     Sources = { input },
                 },
             }.RunAsync();
+
+            await new VerifyCSV2.Test
+            {
+                ReferenceAssemblies = ReferenceAssemblies,
+                TestState =
+                {
+                    AdditionalReferences = { RefitAssembly },
+                    Sources = { input },
+                },
+            }.RunAsync();
         }
 
         [Fact]
@@ -640,6 +652,24 @@ namespace Refit.Implementation
                     },
                 },
             }.RunAsync();
+
+            await new VerifyCSV2.Test
+            {
+                ReferenceAssemblies = ReferenceAssemblies,
+                TestState =
+                {
+                    AdditionalReferences = { RefitAssembly },
+                    Sources = { input },
+                    GeneratedSources =
+                    {
+                        (typeof(InterfaceStubGeneratorV2), "PreserveAttribute.g.cs", output1),
+                        (typeof(InterfaceStubGeneratorV2), "Generated.g.cs", output1_5),
+                        (typeof(InterfaceStubGeneratorV2), "IGitHubApi.g.cs", output2),
+                        (typeof(InterfaceStubGeneratorV2), "IGitHubApiDisposable.g.cs", output3),
+                        (typeof(InterfaceStubGeneratorV2), "INestedGitHubApi.g.cs", output4),
+                    },
+                },
+            }.RunAsync();
         }
 
 
@@ -768,6 +798,22 @@ namespace Refit.Implementation
                     },
                 },
             }.RunAsync();
+
+            await new VerifyCSV2.Test
+            {
+                ReferenceAssemblies = ReferenceAssemblies,
+                TestState =
+                {
+                    AdditionalReferences = { RefitAssembly },
+                    Sources = { input },
+                    GeneratedSources =
+                    {
+                        (typeof(InterfaceStubGeneratorV2), "PreserveAttribute.g.cs", output1),
+                        (typeof(InterfaceStubGeneratorV2), "Generated.g.cs", output1_5),
+                        (typeof(InterfaceStubGeneratorV2), "IServiceWithoutNamespace.g.cs", output2),
+                    },
+                },
+            }.RunAsync();
         }
     }
 

Refit.Tests/Refit.Tests.csproj

@@ -18,13 +18,14 @@
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" />
     <PackageReference Include="System.Reactive" Version="5.0.0" />    
     <PackageReference Include="Microsoft.AspNetCore.WebUtilities" Version="2.2.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.8.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.0.0-2.final" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing.XUnit" Version="1.1.0" />
     <PackageReference Include="RichardSzalay.MockHttp" Version="6.0.0" />
     <ProjectReference Include="..\Refit.HttpClientFactory\Refit.HttpClientFactory.csproj" />
     <ProjectReference Include="..\Refit.Newtonsoft.Json\Refit.Newtonsoft.Json.csproj" />
-    <ProjectReference Include="..\InterfaceStubGenerator.Core\InterfaceStubGenerator.Core.csproj"
+    <ProjectReference Include="..\InterfaceStubGenerator.Roslyn38\InterfaceStubGenerator.Roslyn38.csproj"
                             OutputItemType="Analyzer" ReferenceOutputAssembly="true" />
+    <ProjectReference Include="..\InterfaceStubGenerator.Roslyn40\InterfaceStubGenerator.Roslyn40.csproj" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net461' ">

Refit.Tests/Verifiers/CSharpIncrementalSourceGeneratorVerifier`1+Test.cs

@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Testing;
+using Microsoft.CodeAnalysis.Testing;
+using Microsoft.CodeAnalysis.Testing.Verifiers;
+
+namespace Refit.Tests
+{
+    public static partial class CSharpIncrementalSourceGeneratorVerifier<TIncrementalGenerator>
+        where TIncrementalGenerator : IIncrementalGenerator, new()
+    {
+        public class Test : CSharpSourceGeneratorTest<EmptySourceGeneratorProvider, XUnitVerifier>
+        {
+            public Test()
+            {
+                SolutionTransforms.Add((solution, projectId) =>
+                {
+                    var compilationOptions = solution.GetProject(projectId).CompilationOptions;
+                    compilationOptions = compilationOptions.WithSpecificDiagnosticOptions(
+                        compilationOptions.SpecificDiagnosticOptions.SetItems(CSharpVerifierHelper.NullableWarnings));
+                    solution = solution.WithProjectCompilationOptions(projectId, compilationOptions);
+
+                    return solution;
+                });
+            }
+
+            protected override IEnumerable<ISourceGenerator> GetSourceGenerators()
+            {
+                yield return new TIncrementalGenerator().AsSourceGenerator();
+            }
+
+            protected override ParseOptions CreateParseOptions()
+            {
+                var parseOptions = (CSharpParseOptions)base.CreateParseOptions();
+                return parseOptions.WithLanguageVersion(LanguageVersion.Preview);
+            }
+        }
+    }
+}

Refit.Tests/Verifiers/CSharpIncrementalSourceGeneratorVerifier`1.cs

@@ -0,0 +1,9 @@
+using Microsoft.CodeAnalysis;
+
+namespace Refit.Tests
+{
+    public static partial class CSharpIncrementalSourceGeneratorVerifier<TIncrementalGenerator>
+        where TIncrementalGenerator : IIncrementalGenerator, new()
+    {
+    }
+}

Refit.sln

@@ -23,9 +23,18 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Refit.HttpClientFactory", "
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Refit.Newtonsoft.Json", "Refit.Newtonsoft.Json\Refit.Newtonsoft.Json.csproj", "{2210E606-1C91-4EA0-8876-3B2F501F2669}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "InterfaceStubGenerator.Core", "InterfaceStubGenerator.Core\InterfaceStubGenerator.Core.csproj", "{72869789-0310-4916-9A41-20D16A01C1B8}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "InterfaceStubGenerator.Roslyn38", "InterfaceStubGenerator.Roslyn38\InterfaceStubGenerator.Roslyn38.csproj", "{72869789-0310-4916-9A41-20D16A01C1B8}"
+EndProject
+Project("{D954291E-2A0B-460D-934E-DC6B0785DB48}") = "InterfaceStubGenerator.Shared", "InterfaceStubGenerator.Shared\InterfaceStubGenerator.Shared.shproj", "{B591423D-F92D-4E00-B0EB-615C9853506C}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "InterfaceStubGenerator.Roslyn40", "InterfaceStubGenerator.Roslyn40\InterfaceStubGenerator.Roslyn40.csproj", "{A4B61169-3314-41DB-8156-BE9677C90C9F}"
 EndProject
 Global
+	GlobalSection(SharedMSBuildProjectFiles) = preSolution
+		InterfaceStubGenerator.Shared\InterfaceStubGenerator.Shared.projitems*{72869789-0310-4916-9a41-20d16a01c1b8}*SharedItemsImports = 5
+		InterfaceStubGenerator.Shared\InterfaceStubGenerator.Shared.projitems*{a4b61169-3314-41db-8156-be9677c90c9f}*SharedItemsImports = 5
+		InterfaceStubGenerator.Shared\InterfaceStubGenerator.Shared.projitems*{b591423d-f92d-4e00-b0eb-615c9853506c}*SharedItemsImports = 13
+	EndGlobalSection
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
 		Debug|ARM = Debug|ARM
@@ -117,6 +126,22 @@ Global
 		{72869789-0310-4916-9A41-20D16A01C1B8}.Release|x64.Build.0 = Release|Any CPU
 		{72869789-0310-4916-9A41-20D16A01C1B8}.Release|x86.ActiveCfg = Release|Any CPU
 		{72869789-0310-4916-9A41-20D16A01C1B8}.Release|x86.Build.0 = Release|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Debug|ARM.ActiveCfg = Debug|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Debug|ARM.Build.0 = Debug|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Debug|x64.Build.0 = Debug|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Debug|x86.Build.0 = Debug|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Release|Any CPU.Build.0 = Release|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Release|ARM.ActiveCfg = Release|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Release|ARM.Build.0 = Release|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Release|x64.ActiveCfg = Release|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Release|x64.Build.0 = Release|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Release|x86.ActiveCfg = Release|Any CPU
+		{A4B61169-3314-41DB-8156-BE9677C90C9F}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

Refit/Refit.csproj

@@ -16,7 +16,8 @@
   <ItemGroup Condition="'$(TargetFramework)' == 'net461'">    
     <Reference Include="System.Web" />
     <PackageReference Include="System.Net.Http" Version="4.3.4" />
-    <ProjectReference Include="..\InterfaceStubGenerator.Core\InterfaceStubGenerator.Core.csproj" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="..\InterfaceStubGenerator.Roslyn38\InterfaceStubGenerator.Roslyn38.csproj" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="..\InterfaceStubGenerator.Roslyn40\InterfaceStubGenerator.Roslyn40.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <ItemGroup Label="Package">        
@@ -25,9 +26,14 @@
 
     <!-- We need this one to catch older clients -->
     <None Include="targets\refit.targets" PackagePath="build\netstandard2.0" Pack="true" />
-    
-    <None Include="..\InterfaceStubGenerator.Core\bin\$(Configuration)\netstandard2.0\InterfaceStubGenerator.Core.dll"
-          PackagePath="analyzers\cs\"
+
+    <None Include="..\InterfaceStubGenerator.Roslyn38\bin\$(Configuration)\netstandard2.0\InterfaceStubGeneratorV1.dll"
+          PackagePath="analyzers\cs\roslyn38"
+          Pack="true"
+          Visible="false" />
+
+    <None Include="..\InterfaceStubGenerator.Roslyn40\bin\$(Configuration)\netstandard2.0\InterfaceStubGeneratorV2.dll"
+          PackagePath="analyzers\cs\roslyn40"
           Pack="true"
           Visible="false" />
   </ItemGroup>

Refit/targets/refit.props

@@ -4,4 +4,17 @@
     <CompilerVisibleProperty Include="RefitInternalNamespace" />
   </ItemGroup>
 
+  <Choose>
+    <When Condition="'$(VisualStudioVersion)' >= '17.0' AND '$(DesignTimeBuild)' == 'True'">
+      <ItemGroup>
+        <Analyzer Include="$(MSBuildThisFileDirectory)../../analyzers/cs/roslyn40/*.dll" />
+      </ItemGroup>
+    </When>
+    <Otherwise>
+      <ItemGroup>
+        <Analyzer Include="$(MSBuildThisFileDirectory)../../analyzers/cs/roslyn38/*.dll" />
+      </ItemGroup>
+    </Otherwise>
+  </Choose>
+
 </Project>