Recently reenabled fuzzing test still needs some work:

It is sporadically failing in CI.

It takes a lot of iterations locally to trip it, but it is possible to repro.

A good way to get a repro locally, (and to stress test a selected test case in general) is to define a xUnit attrbute like this

type RepeatAttribute(count, [<ParamArray>] args: obj array) =
    inherit DataAttribute()
    override _.GetData _ = Seq.init count (fun i -> [| yield! args; i |])

and apply it like this:

[<Theory>]
[<Repeat(100, SignatureFiles.Yes)>]
[<Repeat(100, SignatureFiles.No)>]
[<Repeat(100, SignatureFiles.Some)>]
let Fuzzing signatureFiles _ =

Running the theory in parallel it can be repro'd in around 100 iterations.
Out of curiosity I tried to run this test with useTransparentCompiler = false and it also fails from time to time. It is possible that it reveals some concurrency issue unrelated to TransparentCompiler.