The finalizer is run for a partially constructed object for MonoVM

[marek-safar]

There is a change in .NET Core which makes this code to behave differently than on .NET Framework.

using System;

	class Program {
		static void Main ()
		{
			X x;
			try {
				x = new X ();
			} catch (ApplicationException) {
			}
		}
	}

	class X {
		public X () => throw new ApplicationException ();
		~X () => throw new NotImplementedException ();
	}

With MonoVM it prints

System.NotImplementedException: The method or operation is not implemented.

but it should not (it does not with CoreCLR VM).

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[jkotas]

it does not with CoreCLR VM

Nit: It may or may not throw on CoreCLR. It depends on whether GC collects the X instance before the program shutdowns.

[akoeplinger]

Yeah if I change your code to this then it consistently crashes with the NotImplementedException on CoreCLR too:

using System;

namespace netcorefinalizer
{
    class Program {
        static void Main ()
        {
            CreateX();
            GC.Collect();
            GC.WaitForPendingFinalizers();
        }

        public static void CreateX()
        {
            X x;
            try {
                x = new X ();
            } catch (ApplicationException) {
            }
        }
    }

    class X {
        public X () => throw new ApplicationException ();
        ~X () => throw new NotImplementedException ();
    }
}

[marek-safar]

Interesting, that solves the problem.