Bug 4203 - System.ArgumentException: value must be of a primitive type instead of 'Mono.Debugging.Backend.EvaluationResult'
Summary: System.ArgumentException: value must be of a primitive type instead of 'Mono....
Alias: None
Product: Xamarin Studio
Classification: Desktop
Component: Debugger ()
Version: Trunk
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Jeffrey Stedfast
Depends on:
Reported: 2012-04-03 07:52 UTC by Marek Safar
Modified: 2012-04-11 17:48 UTC (History)
1 user (show)

Is this bug a regression?: ---
Last known good build:

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Description Marek Safar 2012-04-03 07:52:01 UTC
using System;
using System.Threading.Tasks;
using System.Threading;

class Tester
	async Task<int> Lambda_1()
		int res = 1;
			int a = 8;
			Func<int> f = () => { Thread.Sleep(100000); return a; };
			res = await Task.Factory.StartNew(f);
			res += f();

		return res - 16;

	public static int Main()
		var t = new Tester().Lambda_1();
		if (!Task.WaitAll(new[] { t }, 1000))   // Set a breakpoint here and add t.Start () to Watch window, then expand the result value
			return 1;
		return 0;

System.ArgumentException: value must be of a primitive type instead of 'Mono.Debugging.Backend.EvaluationResult'
Parameter name: value
  at Mono.Debugger.Soft.VirtualMachine.CreateValue (System.Object value) [0x0005b] in /home/marek/git/monodevelop/main/contrib/Mono.Debugger.Soft/Mono.Debugger.Soft/VirtualMachine.cs:165 
  at Mono.Debugging.Soft.SoftDebuggerAdaptor.CreateValue (Mono.Debugging.Evaluation.EvaluationContext ctx, System.Object value) [0x0002f] in /home/marek/git/monodevelop/main/src/addins/MonoDevelop.Debugger.Soft/Mono.Debugging.Soft/SoftDebuggerAdaptor.cs:208 
  at Mono.Debugging.Evaluation.LiteralValueReference.get_Value () [0x0001f] in /home/marek/git/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/LiteralValueReference.cs:79 
  at Mono.Debugging.Evaluation.ValueReference.GetChildren (ObjectPath path, Int32 index, Int32 count, Mono.Debugging.Client.EvaluationOptions options) [0x00002] in /home/marek/git/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/ValueReference.cs:201
Comment 1 Jeffrey Stedfast 2012-04-11 14:05:22 UTC
The cause of this issue is in NRefactoryEvaluator.cs on line 493:

				return LiteralValueReference.CreateObjectLiteral (ctx, name, new EvaluationResult ("No return value."));

Unfortunately I can't get your sample to build, so it's kinda hard to test, but can you try changing that line to call

LiteralValueReference.Create*Target*ObjectLiteral (... ?

I think that should fix this.
Comment 2 Jeffrey Stedfast 2012-04-11 14:12:21 UTC
Just applied this patch to git master of monodevelop, so you could just try that instead of manually editing the sources.
Comment 3 Jeffrey Stedfast 2012-04-11 17:48:49 UTC
Had to follow up with more fixes, but I think I got it now.