Creating Roslyn MetadataFileReference bombs on mono/Linux - mono

Question

I'm doing on some basic Roslyn stuff, and have run into what appears to be a mono compatibility issue. Wanted to make sure I'm not doing something wrong and hear other people's experience. Am using Roslyn from the Microsoft.CodeAnalysis nuget, version 0.7.4091001-beta (latest).
var mscorlib = new MetadataFileReference(typeof(object).Assembly.Location);
var compilation = CSharpCompilation.Create("Temp", new SyntaxTree[0], new[] { mscorlib });
compilation.GetAssemblyOrModuleSymbol(mscorlib);
While this works on Microsoft .NET, on mono on Linux the last line produces the following exception:
[ERROR] FATAL UNHANDLED EXCEPTION: System.ArgumentException: Absolute path expected.
Parameter name: fullPath
at Microsoft.CodeAnalysis.CommonReferenceManager`2[Microsoft.CodeAnalysis.CSharp.CSharpCompilation,Microsoft.CodeAnalysis.CSharp.Symbols.AssemblySymbol].ResolveMetadataReferences (Microsoft.CodeAnalysis.CSharp.CSharpCompilation compilation, System.Collections.Immutable.ImmutableArray`1& references, IDictionary`2& boundReferenceDirectiveMap, System.Collections.Immutable.ImmutableArray`1& boundReferenceDirectives, System.Collections.Immutable.ImmutableArray`1& assemblies, System.Collections.Immutable.ImmutableArray`1& modules, Microsoft.CodeAnalysis.DiagnosticBag diagnostics) [0x00000] in <filename unknown>:0
at Microsoft.CodeAnalysis.CSharp.CSharpCompilation+ReferenceManager.CreateAndSetSourceAssemblyFullBind (Microsoft.CodeAnalysis.CSharp.CSharpCompilation compilation) [0x00000] in <filename unknown>:0
at Microsoft.CodeAnalysis.CSharp.CSharpCompilation+ReferenceManager.CreateSourceAssemblyForCompilation (Microsoft.CodeAnalysis.CSharp.CSharpCompilation compilation) [0x00000] in <filename unknown>:0
at Microsoft.CodeAnalysis.CSharp.CSharpCompilation.GetBoundReferenceManager () [0x00000] in <filename unknown>:0
at Microsoft.CodeAnalysis.CSharp.CSharpCompilation.GetAssemblyOrModuleSymbol (Microsoft.CodeAnalysis.MetadataReference reference) [0x00000] in <filename unknown>:0
at Microsoft.CodeAnalysis.CSharp.CSharpCompilation.CommonGetAssemblyOrModuleSymbol (Microsoft.CodeAnalysis.MetadataReference reference) [0x00000] in <filename unknown>:0
at Microsoft.CodeAnalysis.Compilation.GetAssemblyOrModuleSymbol (Microsoft.CodeAnalysis.MetadataReference reference) [0x00000] in <filename unknown>:0
at playground2.MainClass.Main (System.String[] args) [0x00000] in <filename unknown>:0
There's obviously some sort of path parsing Linux/Windows sadness going on here. My current workaround is to create the reference to corlib thus:
var mscorlibMetadata = AssemblyMetadata.CreateFromImageStream(new FileStream(typeof(object).Assembly.Location, FileMode.Open, FileAccess.Read));
var mscorlib = new MetadataImageReference (mscorlibMetadata);
Does anybody know anything about this?

Answer 1

This is a bug in Roslyn.
You can send them a pull request to fix PathUtilities.GetPathKind to be aware of Linux-style paths by checking Path.DirectorySeparatorChar.