[Mono-bugs] [Bug 475246] New: Compiler throws exception when List<> is a out parameter of a delegate

[bugzilla_noreply at novell.com]

https://bugzilla.novell.com/show_bug.cgi?id=475246


           Summary: Compiler throws exception when List<> is a out
                    parameter of a delegate
    Classification: Mono
           Product: Mono: Compilers
           Version: 2.4.x
          Platform: x86-64
        OS/Version: RHEL 4
            Status: NEW
          Severity: Normal
          Priority: P5 - None
         Component: C#
        AssignedTo: mono-bugs at lists.ximian.com
        ReportedBy: phamorsky at yahoo.com
         QAContact: mono-bugs at lists.ximian.com
          Found By: ---


User-Agent:       Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; WOW64;
SV1; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.04506.648)

I'm getting a compiler exception for the code that follows.  It fails with
today's 2-4 branch and the trunk on Linux.  I believe it has to do with the
List<> container being an out parameter for the delegate.

-Pete

=== Code Sample ===

using System;
using System.Collections.Generic;
using System.Text;

namespace TestComp
{
    class Program
    {
        internal class MyClass
        {
            public delegate void MyDelegate(out List<int> intToAdd);
            private void MyTemplate(MyDelegate myData)
            {
            }
            public void UseATemplate()
            {
                MyTemplate(
                    delegate /* MyDelegate */ (out List<int> intToAdd)
                    {
                        intToAdd = new List<int>();
                        intToAdd.Add(0);
                    }
                );
            }
        }
        static void Main(string[] args)
        {
        }
    }
}



Reproducible: Always

Steps to Reproduce:
1.save sample in cs file.
2.compile sample with gmcs
Actual Results:  
Exception thrown by compiler ...

~/projects/mono-trunk/mono_install_linux64/bin/mono
~/projects/mono-trunk/mono_install_linux64/lib/mono/2.0/gmcs.exe Program.cs 
Exception caught by the compiler while compiling:
   Block that caused the problem begin at: Program.cs(21,21):
                     Block being compiled:
[Program.cs(22,21):,Program.cs(25,21):]
System.NullReferenceException: Object reference not set to an instance of an
object
Exception caught by the compiler while compiling:
   Block that caused the problem begin at: Program.cs(18,25):
                     Block being compiled:
[Program.cs(19,13):,Program.cs(27,13):]
Mono.CSharp.InternalErrorException: Program.cs(21,21):
Internal compiler error at Program.cs(18,25):: exception caught while emitting
MethodBuilder [MyClass::UseATemplate]

Unhandled Exception: Mono.CSharp.InternalErrorException: Program.cs(21,21):
---> System.NullReferenceException: Object reference not set to an instance of
an object
  at Mono.CSharp.ParameterReference.DoResolve (Mono.CSharp.EmitContext ec)
[0x00000] 
  at Mono.CSharp.Expression.Resolve (Mono.CSharp.EmitContext ec, ResolveFlags
flags) [0x00000] 
  at Mono.CSharp.Expression.Resolve (Mono.CSharp.EmitContext ec) [0x00000] 
  at Mono.CSharp.SimpleName.DoSimpleNameResolve (Mono.CSharp.EmitContext ec,
Mono.CSharp.Expression right_side, Boolean intermediate) [0x00000] 
  at Mono.CSharp.SimpleName.SimpleNameResolve (Mono.CSharp.EmitContext ec,
Mono.CSharp.Expression right_side, Boolean intermediate) [0x00000] 
  at Mono.CSharp.SimpleName.DoResolve (Mono.CSharp.EmitContext ec, Boolean
intermediate) [0x00000] 
  at Mono.CSharp.Expression.Resolve (Mono.CSharp.EmitContext ec, ResolveFlags
flags) [0x00000] 
  at Mono.CSharp.MemberAccess.DoResolve (Mono.CSharp.EmitContext ec,
Mono.CSharp.Expression right_side) [0x00000] 
  at Mono.CSharp.MemberAccess.DoResolve (Mono.CSharp.EmitContext ec) [0x00000] 
  at Mono.CSharp.Expression.Resolve (Mono.CSharp.EmitContext ec, ResolveFlags
flags) [0x00000] 
  at Mono.CSharp.Invocation.DoResolve (Mono.CSharp.EmitContext ec) [0x00000] 
  at Mono.CSharp.Expression.Resolve (Mono.CSharp.EmitContext ec, ResolveFlags
flags) [0x00000] 
  at Mono.CSharp.Expression.Resolve (Mono.CSharp.EmitContext ec) [0x00000] 
  at Mono.CSharp.ExpressionStatement.ResolveStatement (Mono.CSharp.EmitContext
ec) [0x00000] 
  at Mono.CSharp.StatementExpression.Resolve (Mono.CSharp.EmitContext ec)
[0x00000] 
  at Mono.CSharp.Block.Resolve (Mono.CSharp.EmitContext ec) [0x00000] 
  at Mono.CSharp.EmitContext.ResolveTopBlock (Mono.CSharp.EmitContext
anonymous_method_host, Mono.CSharp.ToplevelBlock block,
Mono.CSharp.ParametersCompiled ip, IMethodData md, System.Boolean& unreachable)
[0x00000] 
  --- End of inner exception stack trace ---
  at Mono.CSharp.AnonymousMethodExpression.Compatible (Mono.CSharp.EmitContext
ec, System.Type type) [0x00000] 
  at Mono.CSharp.AnonymousMethodExpression.ImplicitStandardConversionExists
(Mono.CSharp.EmitContext ec, System.Type delegate_type) [0x00000] 
  at Mono.CSharp.Convert.ImplicitConversionExists (Mono.CSharp.EmitContext ec,
Mono.CSharp.Expression expr, System.Type target_type) [0x00000] 
  at Mono.CSharp.MethodGroupExpr.IsArgumentCompatible (Mono.CSharp.EmitContext
ec, Modifier arg_mod, Mono.CSharp.Argument argument, Modifier param_mod,
System.Type parameter) [0x00000] 
  at Mono.CSharp.MethodGroupExpr.IsApplicable (Mono.CSharp.EmitContext ec,
System.Collections.ArrayList arguments, Int32 arg_count,
System.Reflection.MethodBase& method, System.Boolean& params_expanded_form)
[0x00000] 
  at Mono.CSharp.MethodGroupExpr.OverloadResolve (Mono.CSharp.EmitContext ec,
System.Collections.ArrayList& Arguments, Boolean may_fail, Location loc)
[0x00000] 
  at Mono.CSharp.Invocation.DoResolveOverload (Mono.CSharp.EmitContext ec)
[0x00000] 
  at Mono.CSharp.Invocation.DoResolve (Mono.CSharp.EmitContext ec) [0x00000] 
  at Mono.CSharp.Expression.Resolve (Mono.CSharp.EmitContext ec, ResolveFlags
flags) [0x00000] 
  at Mono.CSharp.Expression.Resolve (Mono.CSharp.EmitContext ec) [0x00000] 
  at Mono.CSharp.ExpressionStatement.ResolveStatement (Mono.CSharp.EmitContext
ec) [0x00000] 
  at Mono.CSharp.StatementExpression.Resolve (Mono.CSharp.EmitContext ec)
[0x00000] 
  at Mono.CSharp.Block.Resolve (Mono.CSharp.EmitContext ec) [0x00000] 
  at Mono.CSharp.EmitContext.ResolveTopBlock (Mono.CSharp.EmitContext
anonymous_method_host, Mono.CSharp.ToplevelBlock block,
Mono.CSharp.ParametersCompiled ip, IMethodData md, System.Boolean& unreachable)
[0x00000] 


Expected Results:  
Compile with out error.

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