Add support for top-level statements

[Dremor]

Input code

Console.WriteLine("Hello, World!");

This is the default code outputted by dotnet new create console

Erroneous output

In app:

// Test.Decompile.App, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
// Program
using System;
using System.Runtime.CompilerServices;

[CompilerGenerated]
internal class Program
{
	private static void <Main>$(string[] args)
	{
		Console.WriteLine("Hello, World!");
	}
}

Exported:

using System;
using System.Runtime.CompilerServices;

[CompilerGenerated]
internal class Program
{
	private static void _003CMain_003E_0024(string[] args)
	{
		Console.WriteLine("Hello, World!");
	}
}

The compiler fails to find any "Main" method, as the "Main" method is incorrectly named.

Details

• Product in use: ILSpy
• Version in use: 11.0.0.9223-preview1+7554c1b0042dddac2a7385cea5b64f12dd52281b

[siegfriedpammer]

see #829 top-level statements/programs are not supported

[siegfriedpammer]

Apparently, the code-gen for top-level statements was changed at some point, and now csc no longer emits a speakable name for the main method, similar to how async main uses a mangled name. I read some discussions regarding this on the runtime/roslyn/csharplang repos, but I don't remember where exactly.

[siegfriedpammer]

Note: the team decided a while back (when this feature was first added to C#) that we are NOT going to add full support for top-level statements/programs in the ILSpy UI or in syntax. The currently planned level of support is that we will replace the name of the method that has the .entrypoint marker with Main so programs compile in C#.

Quote #829

We have no plans to support this feature as it would add a lot of complexity to the ILSpy UI as well as the decompiler. "Top level functions/free functions" from IL are already supported: they are located in the synthesized <Module> type, similarly C# top level statements are located in the synthesized Program type.

[Dremor]

Fair enough, but that also happens on other kind of programs. My original issue came from a C# API, which I cannot share as is (customer owned code), but which has the very same result. I'm unable to run the exported result unless I correct that Main method name.

Other decompilers (I tester DotPeek) have no such issue.

[siegfriedpammer]

Top-level statements are just syntactic sugar. The whole program is compiled as Main method and top-level functions are just local functions, which will be detected by ILSpy as usual. ASP.NET minimal APIs are nothing special, everything is just compiled as local function.

[Dremor]

Thank you for your work 😸