CSC: error CS0041: Unexpected error writing debug information -- 'Operation is not supported on this platform.'

Question

Just downloaded Visual Studio Professional for Mac and I cannot seem to build anything as I always get the same error:

/Library/Frameworks/Mono.framework/Versions/4.8.0/lib/mono/xbuild/14.0/bin/Microsoft.CSharp.targets (CoreCompile target) ->

CSC: error CS0041: Unexpected error writing debug information -- 'Operation is not supported on this platform.'

 19 Warning(s)
 1 Error(s)

Not sure what to change on my project to get things to compile.

Answer 1

I was able to work around this problem two ways:

1. HACK By removing debug symbols from the build (in VS windows: Project Properties -> Build Tab -> Advanced button -> change "Debug Info" dropdown to "none" -- not sure what equivalent is in VS for Mac / Xamarin Studio) I did this for all configurations of affected project(s). Pulled back to macOS env, build now succeeds. No debug info of course, but it works without breaking any deps.

2. NON-HACK Root cause is the use of Roslyn compiler/tools for ASP.NET Web projects, and this tool produces PDB files instead of MDB files, and the build fails trying to produce PDB files on macOS platform (er go "platform unsupported".) Knowing the root cause we can also remove the following nuget packages from the affected projects:

   <package id="Microsoft.CodeDom.Providers.DotNetCompilerPlatform" version="1.0.0" targetFramework="net45" />
   <package id="Microsoft.Net.Compilers" version="1.0.0" targetFramework="net45" developmentDependency="true" />
   

It's unclear what is sacrificed by removing these two packages. This does allow me to build the affected projects with the debug info included. The affected projects only contained webapi endpoints, and no use of MVC nor Razor engine. It would be nice to hear the experiences of others if they had issues upstream from this change.

HTH