Stack overflow despite tail call position but only in 64-bit

Question

Originated from this question, I have this little F# code (github) to generate random values according to a normal distribution:

// val nextSingle : (unit -&         


        

Answer 1

Looks like a bug in the compiler's sequence expression compilation mechanism. Here's a simplified repro:

let rec loop r = seq {
    if r > 0 then
        let rec unused() = unused()
        yield r
        yield! loop r
}

printfn "%i" (Seq.nth 10000000 (loop 1))

Obviously the presence of the unused recursive definition shouldn't affect whether this generates a stack overflow, but it does.