RS0031 when using multiple BannedSymbols.txt files

[drewnoakes]

Analyzer

Diagnostic ID: RS0031: The symbol '' is listed multiple times in the list of banned APIs

Describe the bug

In dotnet/project-system we use the banned API analyzer. We also have a project that targets net472 and net8.0.

I want to ban an API in net472 only.

To do this, I have something like:

<ItemGroup>
  <AdditionalFiles Include="$(MSBuildThisFileDirectory)src\Common\BannedSymbols.txt" />
  <AdditionalFiles Include="$(MSBuildThisFileDirectory)src\Common\BannedSymbols.net472.txt" Condition="'$(TargetFramework)' == 'net472'" />
</ItemGroup>

With this, I get a bunch of warnings:

3>D:\repos\project-system\src\Common\BannedSymbols.net472.txt(6,1,6,2): warning RS0031: The symbol '' is listed multiple times in the list of banned APIs (https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md)
3>D:\repos\project-system\src\Common\BannedSymbols.txt(4,1,4,2): warning RS0031: The symbol '' is listed multiple times in the list of banned APIs (https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md)
3>D:\repos\project-system\src\Common\BannedSymbols.txt(3,1,3,10): warning RS0031: The symbol '' is listed multiple times in the list of banned APIs (https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md)
3>D:\repos\project-system\src\Common\BannedSymbols.txt(5,1,5,16): warning RS0031: The symbol '' is listed multiple times in the list of banned APIs (https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md)
3>D:\repos\project-system\src\Common\BannedSymbols.txt(6,1,6,17): warning RS0031: The symbol '' is listed multiple times in the list of banned APIs (https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md)
3>D:\repos\project-system\src\Common\BannedSymbols.txt(7,1,7,16): warning RS0031: The symbol '' is listed multiple times in the list of banned APIs (https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md)
3>D:\repos\project-system\src\Common\BannedSymbols.txt(8,1,8,19): warning RS0031: The symbol '' is listed multiple times in the list of banned APIs (https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md)
3>D:\repos\project-system\src\Common\BannedSymbols.txt(9,1,9,15): warning RS0031: The symbol '' is listed multiple times in the list of banned APIs (https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md)

It seems incorrect that the symbol name should be empty. The files don't have anything interesting in them, and if I only use one file then everything works fine. I don't believe this is related to #6633.

I couldn't get this working, regardless of warnings.