Bug 12361 - Yield return generates invalid IL code
Summary: Yield return generates invalid IL code
Status: RESOLVED FIXED
Alias: None
Product: Compilers
Classification: Mono
Component: C# ()
Version: unspecified
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Marek Safar
URL:
Depends on:
Blocks:
 
Reported: 2013-05-23 10:43 UTC by koczkatamas
Modified: 2013-05-28 05:15 UTC (History)
1 user (show)

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

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Related Links:
Status:
RESOLVED FIXED

Description koczkatamas 2013-05-23 10:43:17 UTC
Tested on http://www.compileonline.com/compile_csharp_online.php.

Input:
---------------------------------------------------------------------------------
using System;
using System.Linq;
using System.Collections.Generic;

public class Test
{
    public static void Main()
	{
		var x = Test2();
        Console.WriteLine(x == null ? "null" : x.Count().ToString());
	}
    
    public static IEnumerable<int> Test2(){
        while(false)
            yield return 5;            
    }
}
---------------------------------------------------------------------------------

Result:
---------------------------------------------------------------------------------
Compiling the source code....
$mcs main.cs -out:demo.exe 2>&1
main.cs(15,13): warning CS0162: Unreachable code detected
Compilation succeeded - 1 warning(s)

Executing the program....
$mono demo.exe 
Unhandled Exception: System.InvalidProgramException: Invalid IL code in Test/c__Iterator0:MoveNext (): IL_0018: unused28  


  at System.Linq.Enumerable.Count[Int32] (IEnumerable`1 source) [0x00000] in :0 
  at Test.Main () [0x00000] in :0 
---------------------------------------------------------------------------------
Comment 1 Marek Safar 2013-05-28 05:15:17 UTC
Fixed in master