Using Double.Nan can cause SetAsmInfo to fail

This code will cause it to fail:

    public class Utils
    {
        // this produces invalid IL code during SetAssemblyInfo.
        public double Value => double.NaN;
    }

This generates the following IL code which is not valid:

    IL_0000:  ldc.r8     -nan(ind)

The issue was introduced in .NET 4.8 and can probably be fixed by search/replace -nan(ind) for something else. I suggest we just dont use 4.8.

A quick patch can be done by using the code below:

namespace NanTest
{
    public class Utils
    {
        // this produces invalid IL code during SetAssemblyInfo.
        //public double Value => double.NaN;
        // do this instead:
        static double zero = 0.0;
        public static double Value => zero / zero;
    }

    public class Program
    {
        public static void Main()
        {
            if (double.IsNaN(Utils.Value))
            {
                Console.WriteLine("NAN");
            }
            else
            {
                Console.WriteLine("NOT NAN");
            }
        }
    }
}

Replace ment values:

// these codes are invalid
IL_0000:  ldc.r8     -nan(ind)
IL_0000:  ldc.r8     -inf
IL_0000:  ldc.r8     inf
IL_0000:  ldc.r4     -nan(ind)
IL_0000:  ldc.r4     -inf
IL_0000:  ldc.r4     inf

// replace with these
IL_0000:  ldc.r8     (00 00 00 00 00 00 F8 FF)
IL_0000:  ldc.r8     (00 00 00 00 00 00 F0 FF)
IL_0000:  ldc.r8     (00 00 00 00 00 00 F0 7F)
IL_0000:  ldc.r4     (00 00 C0 FF)
IL_0000:  ldc.r4     (00 00 80 FF)
IL_0000:  ldc.r4     (00 00 80 7F)

Related MS issues:

Edited Aug 31, 2020 by Rolf Madsen