public override void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
 {
     sb.Append(nameMangler.CompilationUnitPrefix);
     sb.Append("GenericLookupSignature(");
     sb.Append(_runtimeLookupKind.ToString());
     sb.Append(" / ");
     sb.Append(_fixupKind.ToString());
     sb.Append(": ");
     if (_typeArgument != null)
     {
         RuntimeDeterminedTypeHelper.WriteTo(_typeArgument, sb);
     }
     else if (_methodArgument != null)
     {
         RuntimeDeterminedTypeHelper.WriteTo(_methodArgument.Method, sb);
         if (!_methodArgument.Token.IsNull)
         {
             sb.Append(" [");
             sb.Append(_methodArgument.Token.MetadataReader.GetString(_methodArgument.Token.MetadataReader.GetAssemblyDefinition().Name));
             sb.Append(":");;
             sb.Append(((uint)_methodArgument.Token.Token).ToString("X8"));
             sb.Append("]");
         }
     }
     else
     {
         throw new NotImplementedException();
     }
     sb.Append(" (");
     sb.Append(_methodContext.ToString());
     sb.Append(")");
 }