[Mono-bugs] [Bug 659771] New: gmcs: anon method that captures local var in finalizer crashes compiler

[bugzilla_noreply at novell.com]

https://bugzilla.novell.com/show_bug.cgi?id=659771

https://bugzilla.novell.com/show_bug.cgi?id=659771#c0


           Summary: gmcs: anon method that captures local var in finalizer
                    crashes compiler
    Classification: Mono
           Product: Mono: Compilers
           Version: 2.8.x
          Platform: Macintosh
        OS/Version: Mac OS X 10.6
            Status: NEW
          Severity: Normal
          Priority: P5 - None
         Component: C#
        AssignedTo: msafar at novell.com
        ReportedBy: brian at sooloos.com
         QAContact: mono-bugs at lists.ximian.com
          Found By: ---
           Blocker: ---


User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_5; en-US)
AppleWebKit/534.13 (KHTML, like Gecko) Chrome/9.0.597.19 Safari/534.13

If I try to compile an anonymous method inside of a finalizer and it captures a
variable in the local scope of the finalizer, gmcs crashes.

Yes, I am aware of how weird it is to do this and how obscure a case it really
is :)

brian at brianmbp ~ $ cat t.cs                                                     
using System;
using System.Threading;

class Foo {
    ~Foo() {
        int x = 1;
        new Thread(() => Console.WriteLine("{0}", x));
    }
    public static void Main(string[] args) { }
}
brian at brianmbp ~ $ gmcs t.cs

Unhandled Exception: System.NullReferenceException: Object reference not set to
an instance of an object
  at Mono.CSharp.HoistedVariable.GetFieldExpression (Mono.CSharp.EmitContext
ec) [0x00000] in <filename unknown>:0 
  at Mono.CSharp.HoistedVariable.EmitAssign (Mono.CSharp.EmitContext ec,
Mono.CSharp.Expression source, Boolean leave_copy, Boolean prepare_for_load)
[0x00000] in <filename unknown>:0 
  at Mono.CSharp.VariableReference.EmitAssign (Mono.CSharp.EmitContext ec,
Mono.CSharp.Expression source, Boolean leave_copy, Boolean prepare_for_load)
[0x00000] in <filename unknown>:0 
  at Mono.CSharp.Assign.Emit (Mono.CSharp.EmitContext ec, Boolean is_statement)
[0x00000] in <filename unknown>:0 
  at Mono.CSharp.Assign.EmitStatement (Mono.CSharp.EmitContext ec) [0x00000] in
<filename unknown>:0 
  at Mono.CSharp.StatementExpression.DoEmit (Mono.CSharp.EmitContext ec)
[0x00000] in <filename unknown>:0 
  at Mono.CSharp.Statement.Emit (Mono.CSharp.EmitContext ec) [0x00000] in
<filename unknown>:0 
  at Mono.CSharp.Block.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in
<filename unknown>:0 
  at Mono.CSharp.Block.Emit (Mono.CSharp.EmitContext ec) [0x00000] in <filename
unknown>:0 
  at Mono.CSharp.TryFinally.EmitTryBody (Mono.CSharp.EmitContext ec) [0x00000]
in <filename unknown>:0 
  at Mono.CSharp.ExceptionStatement.DoEmit (Mono.CSharp.EmitContext ec)
[0x00000] in <filename unknown>:0 
  at Mono.CSharp.Statement.Emit (Mono.CSharp.EmitContext ec) [0x00000] in
<filename unknown>:0 
  at Mono.CSharp.Block.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in
<filename unknown>:0 
  at Mono.CSharp.Block.Emit (Mono.CSharp.EmitContext ec) [0x00000] in <filename
unknown>:0 
  at Mono.CSharp.ExplicitBlock.Emit (Mono.CSharp.EmitContext ec) [0x00000] in
<filename unknown>:0 
  at Mono.CSharp.ToplevelBlock.Emit (Mono.CSharp.EmitContext ec) [0x00000] in
<filename unknown>:0 
  at Mono.CSharp.MethodData.Emit (Mono.CSharp.DeclSpace parent) [0x00000] in
<filename unknown>:0 
  at Mono.CSharp.MethodOrOperator.Emit () [0x00000] in <filename unknown>:0 
  at Mono.CSharp.Destructor.Emit () [0x00000] in <filename unknown>:0 
  at Mono.CSharp.TypeContainer.EmitType () [0x00000] in <filename unknown>:0 
  at Mono.CSharp.RootContext.EmitCode () [0x00000] in <filename unknown>:0 
  at Mono.CSharp.Driver.Compile () [0x00000] in <filename unknown>:0 
  at Mono.CSharp.Driver.Main (System.String[] args) [0x00000] in <filename
unknown>:0 
  at Mono.CSharp.Driver.Main (System.String[] args) [0x00000] in <filename
unknown>:0 

Reproducible: Always




This is easily worked around by moving the the code containing the anon method
to a separate method or static method on the class.

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