build: support only Roslyn 4.14 + 5.0 (drop 4.8/4.12 bands)

VS 2022 17.8 (Roslyn 4.8) is EOL and 17.12 (4.12) is nearly EOL; 17.14
(4.14) is the only serviced VS 2022 baseline. Set CodeAnalysisVersion to
4.14, rename the Roslyn4120 variant to Roslyn4140 (4.14), delete Roslyn480,
and ship only the roslyn4.14 + roslyn5.0 analyzer bands. Repoint all
consumers + the test project (was pinned to 4.12, which broke against the
4.14 CodeFixes assembly). Rationale documented in README.

Author: glennawatson

README.md

@@ -72,6 +72,17 @@ Splat.Locator.CurrentMutable.RegisterViewsForViewModelsSourceGenerated();
 - For ReactiveUI versions **older than V19.5.31**, all `[ReactiveCommand]` options are supported except for async methods with a `CancellationToken`.
 - For **.NET Framework 4.8 and older**, add [Polyfill by Simon Cropp](https://github.com/SimonCropp/Polyfill) or [PolySharp by Sergio Pedri](https://github.com/Sergio0694/PolySharp) to your project and set the `LangVersion` to 12.0 or later in your project file.
 
+### Roslyn / Visual Studio support
+
+The generators ship two Roslyn analyzer bands and the matching one is selected automatically by your compiler:
+
+| Band (`analyzers/dotnet/...`) | Roslyn | Tooling |
+| --- | --- | --- |
+| `roslyn4.14` | 4.14 | Visual Studio 2022 17.14, .NET SDK 9.0.3xx |
+| `roslyn5.0` | 5.0 | Visual Studio 2026, .NET 10 SDK |
+
+**Why only 4.14 and 5.0?** Per the [Visual Studio 2022 lifecycle](https://learn.microsoft.com/en-us/lifecycle/products/visual-studio-2022), **17.14 (Roslyn 4.14) is the only serviced VS 2022 baseline** — 17.8 (Roslyn 4.8) is already out of support, and 17.12 (Roslyn 4.12) reaches end of support shortly. Rather than carry soon-to-be-unsupported bands, we target the latest supported VS 2022 Roslyn (4.14) as the baseline and ship a 5.0 band for VS 2026 / .NET 10. If you are on an older Roslyn, stay on a previous release of this package or update Visual Studio.
+
 For more information on analyzer codes, see the [analyzer codes documentation](https://github.com/reactiveui/ReactiveUI.SourceGenerators/blob/main/src/ReactiveUI.SourceGenerators/AnalyzerReleases.Shipped.md).
 
 ---

src/ReactiveUI.SourceGenerator.Tests/ReactiveUI.SourceGenerators.Tests.csproj

@@ -18,11 +18,11 @@
     <PackageReference Include="TUnit" />
     <PackageReference Include="Verify.TUnit" />
     <PackageReference Include="Verify.SourceGenerators" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" VersionOverride="4.12.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Common" PrivateAssets="all" VersionOverride="4.12.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" PrivateAssets="all" VersionOverride="4.12.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis" PrivateAssets="all" VersionOverride="4.12.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" PrivateAssets="all" VersionOverride="4.12.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" VersionOverride="4.14.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Common" PrivateAssets="all" VersionOverride="4.14.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" PrivateAssets="all" VersionOverride="4.14.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis" PrivateAssets="all" VersionOverride="4.14.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" PrivateAssets="all" VersionOverride="4.14.0" />
     <PackageReference Include="ReactiveUI" />
     <PackageReference Include="Splat" />
   </ItemGroup>
@@ -61,7 +61,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\ReactiveUI.SourceGenerators.Analyzers.CodeFixes\ReactiveUI.SourceGenerators.Analyzers.CodeFixes.csproj" />
-    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4120\ReactiveUI.SourceGenerators.Roslyn4120.csproj" />
+    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4140\ReactiveUI.SourceGenerators.Roslyn4140.csproj" />
   </ItemGroup>
 
 </Project>

src/ReactiveUI.SourceGenerators.Execute.Maui/ReactiveUI.SourceGenerators.Execute.Maui.csproj

@@ -24,7 +24,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4120\ReactiveUI.SourceGenerators.Roslyn4120.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4140\ReactiveUI.SourceGenerators.Roslyn4140.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
     <ProjectReference Include="..\ReactiveUI.SourceGenerators.Analyzers.CodeFixes\ReactiveUI.SourceGenerators.Analyzers.CodeFixes.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false"  />
   </ItemGroup>
 

src/ReactiveUI.SourceGenerators.Execute.Nested1/ReactiveUI.SourceGenerators.Execute.Nested1.csproj

@@ -10,7 +10,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4120\ReactiveUI.SourceGenerators.Roslyn4120.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" PrivateAssets="all" />
+    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4140\ReactiveUI.SourceGenerators.Roslyn4140.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>

src/ReactiveUI.SourceGenerators.Execute.Nested2/ReactiveUI.SourceGenerators.Execute.Nested2.csproj

@@ -10,7 +10,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4120\ReactiveUI.SourceGenerators.Roslyn4120.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" PrivateAssets="all" />
+    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4140\ReactiveUI.SourceGenerators.Roslyn4140.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" PrivateAssets="all" />
     <ProjectReference Include="..\ReactiveUI.SourceGenerators.Execute.Nested1\ReactiveUI.SourceGenerators.Execute.Nested1.csproj" />
   </ItemGroup>
 

src/ReactiveUI.SourceGenerators.Execute.Nested3/ReactiveUI.SourceGenerators.Execute.Nested3.csproj

@@ -10,7 +10,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4120\ReactiveUI.SourceGenerators.Roslyn4120.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" PrivateAssets="all" />
+    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4140\ReactiveUI.SourceGenerators.Roslyn4140.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" PrivateAssets="all" />
     <ProjectReference Include="..\ReactiveUI.SourceGenerators.Execute.Nested2\ReactiveUI.SourceGenerators.Execute.Nested2.csproj" />
   </ItemGroup>
 

…iveUI.SourceGenerators.Roslyn4120.csproj …iveUI.SourceGenerators.Roslyn4140.csprojsrc/ReactiveUI.SourceGenerators.Roslyn4120/ReactiveUI.SourceGenerators.Roslyn4120.csproj renamed to src/ReactiveUI.SourceGenerators.Roslyn4140/ReactiveUI.SourceGenerators.Roslyn4140.csproj src/ReactiveUI.SourceGenerators.Roslyn4120/ReactiveUI.SourceGenerators.Roslyn4120.csproj renamed to src/ReactiveUI.SourceGenerators.Roslyn4140/ReactiveUI.SourceGenerators.Roslyn4140.csproj

@@ -14,15 +14,16 @@
 
     <PackageDescription>A MVVM framework that integrates with the Reactive Extensions for .NET to create elegant, testable User Interfaces that run on any mobile or desktop platform. This is the Source Generators package for ReactiveUI</PackageDescription>
     <AssemblyName>ReactiveUI.SourceGenerators</AssemblyName>
+    <!-- ROSYLN_412 is the "Roslyn 4.12+ API surface" feature flag; 4.14 satisfies it. -->
     <DefineConstants>$(DefineConstants);ROSYLN_412</DefineConstants>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" VersionOverride="4.12.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Common" PrivateAssets="all" VersionOverride="4.12.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" PrivateAssets="all" VersionOverride="4.12.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis" PrivateAssets="all" VersionOverride="4.12.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" PrivateAssets="all" VersionOverride="4.12.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" VersionOverride="4.14.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Common" PrivateAssets="all" VersionOverride="4.14.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" PrivateAssets="all" VersionOverride="4.14.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis" PrivateAssets="all" VersionOverride="4.14.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" PrivateAssets="all" VersionOverride="4.14.0" />
   </ItemGroup>
 
   <ItemGroup>

src/ReactiveUI.SourceGenerators.Roslyn480/ReactiveUI.SourceGenerators.Roslyn480.csproj

@@ -22,8 +22,7 @@
   </Folder>
   <Project Path="ReactiveUI.SourceGenerator.Tests/ReactiveUI.SourceGenerators.Tests.csproj" />
   <Project Path="ReactiveUI.SourceGenerators.Analyzers.CodeFixes/ReactiveUI.SourceGenerators.Analyzers.CodeFixes.csproj" />
-  <Project Path="ReactiveUI.SourceGenerators.Roslyn4120/ReactiveUI.SourceGenerators.Roslyn4120.csproj" />
-  <Project Path="ReactiveUI.SourceGenerators.Roslyn480/ReactiveUI.SourceGenerators.Roslyn480.csproj" />
+  <Project Path="ReactiveUI.SourceGenerators.Roslyn4140/ReactiveUI.SourceGenerators.Roslyn4140.csproj" />
   <Project Path="ReactiveUI.SourceGenerators.Roslyn5000/ReactiveUI.SourceGenerators.Roslyn5000.csproj" />
   <Project Path="ReactiveUI.SourceGenerators/ReactiveUI.SourceGenerators.csproj" />
 </Solution>

src/ReactiveUI.SourceGenerators.slnx

@@ -30,14 +30,14 @@
   <ItemGroup>
     <ProjectReference Include="..\ReactiveUI.SourceGenerators.Analyzers.CodeFixes\ReactiveUI.SourceGenerators.Analyzers.CodeFixes.csproj" />
     <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn5000\ReactiveUI.SourceGenerators.Roslyn5000.csproj" ReferenceOutputAssembly="false" />
-    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4120\ReactiveUI.SourceGenerators.Roslyn4120.csproj" ReferenceOutputAssembly="false" />
-    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn480\ReactiveUI.SourceGenerators.Roslyn480.csproj" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="..\ReactiveUI.SourceGenerators.Roslyn4140\ReactiveUI.SourceGenerators.Roslyn4140.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
-  <!-- This ensures the library will be packaged as a source generator when we use `dotnet pack` -->
+  <!-- This ensures the library will be packaged as a source generator when we use `dotnet pack`.
+       Only Roslyn 4.14 (VS 2022 17.14 — the only serviced VS 2022 baseline) and 5.0 (VS 2026) are
+       shipped; the 4.8/4.12 bands were dropped — see README for the rationale. -->
   <ItemGroup>
-    <None Include="..\ReactiveUI.SourceGenerators.Roslyn480\bin\$(Configuration)\netstandard2.0\ReactiveUI.SourceGenerators.dll" PackagePath="analyzers\dotnet\roslyn4.8\cs" Pack="true" Visible="false" />
-    <None Include="..\ReactiveUI.SourceGenerators.Roslyn4120\\bin\$(Configuration)\netstandard2.0\ReactiveUI.SourceGenerators.dll" PackagePath="analyzers\dotnet\roslyn4.12\cs" Pack="true" Visible="false" />
-    <None Include="..\ReactiveUI.SourceGenerators.Roslyn5000\\bin\$(Configuration)\netstandard2.0\ReactiveUI.SourceGenerators.dll" PackagePath="analyzers\dotnet\roslyn5.0\cs" Pack="true" Visible="false" />
+    <None Include="..\ReactiveUI.SourceGenerators.Roslyn4140\bin\$(Configuration)\netstandard2.0\ReactiveUI.SourceGenerators.dll" PackagePath="analyzers\dotnet\roslyn4.14\cs" Pack="true" Visible="false" />
+    <None Include="..\ReactiveUI.SourceGenerators.Roslyn5000\bin\$(Configuration)\netstandard2.0\ReactiveUI.SourceGenerators.dll" PackagePath="analyzers\dotnet\roslyn5.0\cs" Pack="true" Visible="false" />
   </ItemGroup>
 </Project>