error FS0192 : internal error : Length of Nullable metadata and needs of its processing do not match: { Data = [|0uy; 1uy|] Idx = 2 }

[Evangelink]

When working on YoloDev/YoloDev.Expecto.TestSdk#152 I suddenly started to get many nullability related failures.

I am hitting this TODO

fsharp/src/Compiler/Checking/import.fs

Lines 269 to 271 in c228ace

	// TODO nullness - once being confident that our bugs are solved and what remains are incoming metadata bugs, remove failwith and replace with dprintfn
	// Testing with .NET compilers other then Roslyn producing nullness metadata?
	failwithf "Length of Nullable metadata and needs of its processing do not match: %A" this

Repro steps

Provide the steps required to reproduce the problem:

1. Clone Add support for Microsoft.Testing.Platform YoloDev/YoloDev.Expecto.TestSdk#152
2. dotnet build

Expected behavior

No error

Actual behavior

error FS0192 : internal error : Length of Nullable metadata and needs of its processing do not match: { Data = [|0uy; 1uy|] Idx = 2 }

Known workarounds

Disable nullability

Related information

SDKS:
3.1.426 [C:\Program Files\dotnet\sdk]
6.0.425 [C:\Program Files\dotnet\sdk]
7.0.410 [C:\Program Files\dotnet\sdk]
8.0.100 [C:\Program Files\dotnet\sdk]
8.0.304 [C:\Program Files\dotnet\sdk]
9.0.100-preview.7.24407.12 [C:\Program Files\dotnet\sdk]
9.0.100-rc.1.24452.12 [C:\Program Files\dotnet\sdk]

[T-Gro]

Thanks for the report.
One of the linked C# dependencies used a nullness metadata format which the F# compiler cannot process, will be some nested generic type which was added via nuget and consumed.

I will check if I can find it and figure the missing case to be handled.

I noticed the linked library uses System.Nullable at a few places, hat would be my first guess (some nested generics involving System.Nullable)

[Evangelink]

If you cannot repo, please let me know what I could provide to help your diagnostic.