Why can't I compile LINQ statements using Mono Evaluator?

Question

I am trying to use C # -Evaluator from a Mono project in MS.NET environment. Simple expressions compile the run. For instance:

var report = new Report(new Printer()); var settings = new CommandLineParser(report).ParseArguments(new string[] { }); var eval = new Evaluator(settings, report); // ensure that the LINQ to object assembly is referenced eval.ReferenceAssembly(typeof(Enumerable).Assembly); eval.Run("using System;"); eval.Run("using System.Collections.Generic;"); eval.Run("using System.Linq;"); // Runs just fine: eval.Run("IEnumerable<string> allData = new string[0];"); eval.Run("Console.Out.WriteLine(allData.Count());"); 

As soon as I cite any LINQ statements, I get exceptions. For instance:

  // Crashes: eval.Run("IEnumerable<string> allData = new string[0];"); eval.Run("var filtered = from d in allData select d;"); eval.Run("Console.Out.WriteLine(filtered.Count());"); 

Error:

 Internal compiler error at Internal(1,1):: exception caught while emitting Name: Host Attributes: 150 Method Signature: Length: 5 Arguments: 0 Signature: 0 0 1 16 28 0 Mono.CSharp.InternalErrorException : VariableInfo is null and the variable `filtered' is not used at Mono.CSharp.LocalVariable.CreateBuilder(EmitContext ec) in statement.cs: line 1593 at Mono.CSharp.BlockVariableDeclaration.DoEmit(EmitContext ec) in statement.cs: line 1368 at Mono.CSharp.Statement.Emit(EmitContext ec) in statement.cs: line 69 at Mono.CSharp.Block.DoEmit(EmitContext ec) in statement.cs: line 2035 at Mono.CSharp.Block.Emit(EmitContext ec) in statement.cs: line 2045 at Mono.CSharp.ExplicitBlock.Emit(EmitContext ec) in statement.cs: line 2177 at Mono.CSharp.ToplevelBlock.Emit(EmitContext ec) in statement.cs: line 2918 at Mono.CSharp.MethodData.Emit(DeclSpace parent) in method.cs: line 2021 at Mono.CSharp.MethodOrOperator.Emit() in method.cs: line 686 at Mono.CSharp.Method.Emit() in method.cs: line 1232 at Mono.CSharp.TypeContainer.EmitType() in class.cs: line 1968 at Mono.CSharp.Evaluator.CompileBlock(Class host, Undo undo, Report Report) in eval.cs: line 659 at Mono.CSharp.Evaluator.Compile(String input, ref CompiledMethod compiled) in eval.cs: line 231 at Mono.CSharp.Evaluator.Evaluate(String input, ref Object result, ref Boolean result_set) in eval.cs: line 298 at Mono.CSharp.Evaluator.Run(String statement) in eval.cs: line 391 

Am I doing something obviously wrong? Or is the Mono expert clearly not ready for use?

Answer 1

Just delete the following line of code:

 // ensure that the LINQ to object assembly is referenced eval.ReferenceAssembly(typeof(Enumerable).Assembly); 

This is not necessary because you already referred to it using directives.