Only enable nullability warnings as errors in C#

Author: Mafii

CodeStyle.sln

@@ -19,6 +19,8 @@ EndProjectSection
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Sandbox", "Sandbox\Sandbox.csproj", "{507A6B2B-4AED-4071-AA38-6EDAF39FDC13}"
 EndProject
+Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "Sandbox.Fsharp", "Sandbox.Fsharp\Sandbox.Fsharp.fsproj", "{971C7344-5A4B-4A76-BFE0-E7611F5FA159}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -56,5 +58,17 @@ Global
 		{507A6B2B-4AED-4071-AA38-6EDAF39FDC13}.Release|x64.Build.0 = Release|Any CPU
 		{507A6B2B-4AED-4071-AA38-6EDAF39FDC13}.Release|x86.ActiveCfg = Release|Any CPU
 		{507A6B2B-4AED-4071-AA38-6EDAF39FDC13}.Release|x86.Build.0 = Release|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Debug|x64.Build.0 = Debug|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Debug|x86.Build.0 = Debug|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Release|Any CPU.Build.0 = Release|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Release|x64.ActiveCfg = Release|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Release|x64.Build.0 = Release|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Release|x86.ActiveCfg = Release|Any CPU
+		{971C7344-5A4B-4A76-BFE0-E7611F5FA159}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

CodeStyle/build/Messerli.CodeStyle.props

@@ -2,7 +2,7 @@
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
     <PropertyGroup>
         <CodeAnalysisRuleSet>$(MSBuildThisFileDirectory)Default.ruleset</CodeAnalysisRuleSet>
-        <WarningsAsErrors>$(WarningsAsErrors);nullable</WarningsAsErrors>
+        <WarningsAsErrors Condition="'$(MSBuildProjectExtension)' == '.csproj'">$(WarningsAsErrors);nullable</WarningsAsErrors>
         <GenerateDocumentationFile>true</GenerateDocumentationFile><!-- This is needed so that analyzers can inspect XML comments. Enforced by SA0001. -->
     </PropertyGroup>
     <ItemGroup>

Sandbox.Fsharp/Library.fs

@@ -0,0 +1,5 @@
+namespace Sandbox.Fsharp
+
+module Say =
+    let hello name =
+        printfn "Hello %s" name

Sandbox.Fsharp/Sandbox.Fsharp.fsproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net5.0</TargetFramework>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <Compile Include="Library.fs"/>
+    </ItemGroup>
+
+</Project>