Repro for type inference bug (or non-specific compiler error message) related to use of byref

Library1.fs

namespace FSharpByrefTypeInferBug

open System.Runtime.InteropServices

#nowarn "9"

type LONG = int32

[<AutoOpen>]
module NativeMethods =
    //
    [<Struct; StructLayout(LayoutKind.Sequential)>]
    type RECT =
        val mutable public left : LONG
        val mutable public top : LONG
        val mutable public right : LONG
        val mutable public bottom : LONG

    [<DllImport("foo.dll")>]
    extern [<MarshalAs(UnmanagedType.Bool)>] bool FooBar (nativeint xyz, RECT& rect)


type Class1() =
    member private __.MyMethod (r : byref<RECT>) =
        printfn "Top: %i" r.top
        ()

    member this.DoStuff () =
        let mutable myRect = Unchecked.defaultof<RECT>
        if FooBar (1234n, &myRect) then
#if ENABLE_WORKAROUND
            // Adding parentheses around the method argument fixes
            // the type resolution for `&myRect`` and allows the
            // program to compile/run as expected.
            this.MyMethod (&myRect)
#else
            // Even though the type of `myRect` is known above, and the compiler
            // infers the type of `&myRect` correctly when calling the FooBar function,
            // attempting to call `MyMethod` with the same argument results in a
            // compiler error:
            // error FS0001: This expression was expected to have type    RECT ref    but here has type    byref<'a>
            this.MyMethod &myRect
#endif