Add AvsEnableDevWarningsNotAsErrors prop (AvaloniaUI#15106)

* Add AvsEnableDevWarningsNotAsErrors prop

* Begone StyleCop

.editorconfig

@@ -159,12 +159,12 @@ dotnet_diagnostic.CA1815.severity = warning
 # CA1820: Test for empty strings using string length
 dotnet_diagnostic.CA1820.severity = warning
 # CA1821: Remove empty finalizers
-dotnet_diagnostic.CA1821.severity = warning
+dotnet_diagnostic.CA1821.severity = error
 # CA1822: Mark members as static
 dotnet_diagnostic.CA1822.severity = suggestion
-# CA1823: Avoid unused private fields
-dotnet_diagnostic.CA1823.severity = warning
 dotnet_code_quality.CA1822.api_surface = private, internal
+# CA1823: Avoid unused private fields
+dotnet_diagnostic.CA1823.severity = error
 # CA1825: Avoid zero-length array allocations
 dotnet_diagnostic.CA1825.severity = warning
 # CA1826: Use property instead of Linq Enumerable method

Avalonia.sln

@@ -120,6 +120,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Props", "Props", "{F3AC8BC1
 		build\UnitTests.NetFX.props = build\UnitTests.NetFX.props
 		build\XUnit.props = build\XUnit.props
 		build\TargetFrameworks.props = build\TargetFrameworks.props
+		build\WarnAsErrors.props = build\WarnAsErrors.props
 	EndProjectSection
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Targets", "Targets", "{4D6FAF79-58B4-482F-9122-0668C346364C}"

Directory.Build.props

@@ -1,6 +1,7 @@
 <Project>
   <Import Project="$(MSBuildThisFileDirectory)/build/AvaloniaPublicKey.props"/>
   <Import Project="$(MSBuildThisFileDirectory)/build/TargetFrameworks.props"/>
+  <Import Project="$(MSBuildThisFileDirectory)/build/WarnAsErrors.props" />
   <PropertyGroup>
       <PackageOutputPath Condition="'$(PackageOutputPath)' == ''">$(MSBuildThisFileDirectory)build-intermediate/nuget</PackageOutputPath>
       <AvaloniaPreviewerNetCoreToolPath>$(MSBuildThisFileDirectory)\src\tools\Avalonia.Designer.HostApp\bin\$(Configuration)\netstandard2.0\Avalonia.Designer.HostApp.dll</AvaloniaPreviewerNetCoreToolPath>

build/WarnAsErrors.props

@@ -0,0 +1,21 @@
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <!-- Keep in sync with .editorconfig -->
+  <PropertyGroup Condition="'$(AvsEnableDevWarningsNotAsErrors)' == 'true'">
+    <!-- CS0649: Field 'field' is never assigned to, and will always have its default value 'value' -->
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);CS0649</WarningsNotAsErrors>
+    <!-- CS0162: Remove unreachable code -->
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);CS0162</WarningsNotAsErrors>
+    <!-- CA2211:Non-constant fields should not be visible -->
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);CA2211</WarningsNotAsErrors>
+    <!-- CA1821: Remove empty finalizers -->
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);CA1821</WarningsNotAsErrors>
+    <!-- CA1823: Avoid unused private fields -->
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);CA1823</WarningsNotAsErrors>
+    <!-- AVLN2203: DuplicateSetterError -->
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);AVLN2203</WarningsNotAsErrors>
+    <!-- AVLN2205: RequiredTemplatePartMissing -->
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);AVLN2205</WarningsNotAsErrors>
+    <!-- AVLN2207: TemplatePartWrongType -->
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);AVLN2207</WarningsNotAsErrors>
+  </PropertyGroup>
+</Project>