Bug 24607 - Compiling enum with mcs 3.6.1 throws System.ArgumentException "Constant does not match the defined type."
Summary: Compiling enum with mcs 3.6.1 throws System.ArgumentException "Constant does ...
Alias: None
Product: Compilers
Classification: Mono
Component: C# ()
Version: 3.6.0
Hardware: PC Windows
: --- minor
Target Milestone: ---
Assignee: Marek Safar
Depends on:
Reported: 2014-11-18 08:06 UTC by Igor
Modified: 2016-02-09 18:39 UTC (History)
2 users (show)

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

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Description Igor 2014-11-18 08:06:58 UTC
Compiling the code below throws System.ArgumentException "Constant does not match the defined type."
Compiling with Visual studio 2012, Mono.Csharp.dll retrieved via nuget:

  public void Test()
    var evaluator = new Mono.CSharp.Evaluator(new CompilerContext(new CompilerSettings(), new CompilingResult()));
    string input = @"
        using System;
        public class Foo {
          public string Bar(string s) { return s.ToUpper(); }
        enum Gender {
          Male = 1,
          Female = 2

If I remove Male and Female enum values, then it compiles ok.

Stack trace:
at System.Reflection.Emit.TypeBuilder.SetConstantValue(ModuleBuilder module, Int32 tk, Type destType, Object value)
at System.Reflection.Emit.FieldBuilder.SetConstant(Object defaultValue)
at Mono.CSharp.Const.Emit()
at Mono.CSharp.TypeDefinition.Emit()
at Mono.CSharp.TypeDefinition.EmitContainer()
at Mono.CSharp.TypeContainer.EmitContainer()
at Mono.CSharp.NamespaceContainer.EmitContainer()
at Mono.CSharp.TypeContainer.EmitContainer()
at Mono.CSharp.ModuleContainer.EmitContainer()
at Mono.CSharp.Evaluator.CompileBlock(Class host, Undo undo, Report Report)
at Mono.CSharp.Evaluator.Compile(String input, CompiledMethod& compiled)
at Mono.CSharp.Evaluator.Compile(String input)
Comment 1 Marek Safar 2014-11-18 11:08:28 UTC
Sadly, this is .net limitation/bug.

C# compiler uses TypeBuilder to define enums, it cannot use EnumBuilder because it does not support nesting.

TypeBuilder does not support SetConstant with unclosed type on .net though.
Comment 2 g.polzoni 2016-02-09 14:03:33 UTC
So it's not possible to define enum?
Comment 3 Marek Safar 2016-02-09 14:38:41 UTC
Not before .net limitations are fixed
Comment 4 Marek Safar 2016-02-09 14:40:00 UTC
Well, we could special case not nested enums but I am not sure it's worth it
Comment 5 g.polzoni 2016-02-09 18:39:20 UTC
Ok. Understood.