ilasm/ildasm does not roundtrip System.Runtime reference assembly

[jkotas]

Repro

Using .NET 10 ilasm + ildasm and .NET 10.0.0 System.Runtime.dll reference assembly:

ildasm System.Runtime.dll" /out:system.Runtime.il
ilasm system.Runtime.il /out:System.Runtime2.dll /DLL
ildasm System.Runtime2.dll" /out:system.Runtime2.il

Actual Result

System.Runtime.il has correct IEqualityOperators definition:

.class interface public abstract auto ansi beforefieldinit System.Numerics.IEqualityOperators`3<(class System.Numerics.IEqualityOperators`3<!TSelf,!TOther,!TResult>) TSelf,TOther,TResult>

System.Runtime2.il has the constraints duplicated in IEqualityOperators definition:

.class interface public abstract auto ansi beforefieldinit System.Numerics.IEqualityOperators`3<(class System.Numerics.IEqualityOperators`3<!TSelf,!TOther,!TResult>, class System.Numerics.IEqualityOperators`3<!TSelf,!TOther,!TResult>) TSelf,TOther,TResult>

Expected result

IEqualityOperators definition of System.Runtime2.il is identical to the one from System.Runtime.dll

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-runtime
See info in area-owners.md if you want to be subscribed.

[ericstj]

The duplication is causing the compiler to emit nullable annotation warnings when building against the reassembled System.Runtime.dll.

We'll workaround it by suppressing the CS8631 warning (as error).

[dotnet-policy-service]

Tagging subscribers to this area: @JulieLeeMSFT
See info in area-owners.md if you want to be subscribed.

[jkotas]

dotnet/dotnet#3873 run into this issue.