.net 10 regression: Different output for algorithm using IBinaryInteger Zero and One #121572
Description
Description
In the process of upgrading from .net 9 to .net 10 I have seen one of my tests fail. It utilizes the IBinaryInteger<T> interface with known values of One and Zero to generate a polynomial string for a crc polynomial.
The generated string now differs in .net 9 and .net 10.
I can of cause simply change the algorithm now that I have updated to .net 10, but I wanted to let you know that this is different across the two versions.
Reproduction Steps
Consider this small C# program:
using System.Numerics;
using System.Text;
var xmodem = new CrcAlgorithm<ushort>(16, 0x1021);
Console.WriteLine(xmodem.GetPolynomialString());
record CrcAlgorithm<T>(int Width, T Polynomial)
where T : IBinaryInteger<T>
{
public string GetPolynomialString()
{
var sb = new StringBuilder();
AppendTerm(sb, Width);
for (var i = Width; i >= 0; i--)
{
var term = Polynomial >> i;
if ((term & T.One) != T.Zero)
{
AppendTerm(sb, i);
}
}
if (sb.Length == 0)
{
sb.Append('0');
}
return sb.ToString();
static void AppendTerm(StringBuilder sb, int degree)
{
if (sb.Length > 0)
{
sb.Append(" + ");
}
if (degree == 0)
{
sb.Append(1);
}
else
{
sb.Append('x');
if (degree > 1)
{
sb.Append('^').Append(degree);
}
}
}
}
}In .net 9 this produced (as expected):
dotnet run -f net9.0
x^16 + x^12 + x^5 + 1
In .net 10 this now produces:
dotnet run -f net10.0
x^16 + x^16 + x^12 + x^5 + 1
It contains an extra inclusion of the x^16 term.
Expected behavior
I expect that the generated string for both .net version produce the same result.
Actual behavior
The output is not the same for the two versions.
Regression?
Yes, this produces the desired output in .net 9.
Known Workarounds
Rewrite the code for generating the polynomial string.
Configuration
No response
Other information
No response