The order in which type forwarders are emitted to ExportedType table is non-deterministic

[tmat]

PEModuleBuilder.GetForwardedTypes enumerates a hash set (http://source.roslyn.io/#Microsoft.CodeAnalysis.CSharp/Emitter/Model/PEModuleBuilder.cs,cef579e20a0e694c,references)

  foreach (NamedTypeSymbol forwardedType in wellKnownAttributeData.ForwardedTypes)
  {
     NamedTypeSymbol originalDefinition = forwardedType.OriginalDefinition;
     ...
     stack.Push(originalDefinition);
     ...
                    while (stack.Count > 0)
                    {
                        NamedTypeSymbol current = stack.Pop();
 ...
                        builder.Add(current);
... 
                    }

  }

[tmat]

@gafter FYI