F# 7.0 generate incorrect program in release config.

[flarelee]

F# 7.0 compiled program failed to run .

Repro steps

// fail to run in release config
// runtime: .net framework 4.7
// F# version: 7.0 12.0.5.0 
// Visual Studio 2022
(*
error message: System.TypeLoadException: 
'Method 'Specialize' on type 'memoizeLatestRef@5-1' from 
assembly 'FSharpCompilerBugs, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' 
tried to implicitly override a method with weaker type parameter constraints.'
*)

let inline refEquals<'a when 'a : not struct> (a : 'a) (b : 'a) = obj.ReferenceEquals (a, b)

let inline tee f x = 
    f x
    x

let memoizeLatestRef (f: 'a -> 'b) =
    let cell = ref None
    let f' (x: 'a) =
        match !cell with
        | Some (x', value) when refEquals x' x -> value
        | _ -> f x |> tee (fun y -> cell := Some (x, y))
    f'

module BugInReleaseConfig = 

    let test f x = 
        printfn "%s" (f x)

    let f: string -> string = memoizeLatestRef id

    let run () = test f "ok"

[<EntryPoint>]
let main argv =
    let culture = System.Globalization.CultureInfo("en")
    System.Globalization.CultureInfo.CurrentCulture <- culture
    System.Globalization.CultureInfo.CurrentUICulture <- culture

    BugInReleaseConfig.run ()

    System.Console.ReadLine() |> ignore
    0

Expected behavior

It should print "ok".

Actual behavior

A System.TypeLoadException was throwed.

Source code
FSharpCompilerBugs.zip

[T-Gro]

I tried reducing this example down and noticed that if I replace the usage of Ref<> (and !, :=) with cell being a mutable variable, it works fine.
Is changing to mutable an option for you, as a temporary workaround at least?

https://sharplab.io/#v2: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=

[flarelee]

@T-Gro Yes, changing to mutable work for me, thanks :)

[nodakai]

I haven't been able to reduce my issue to a minimal repro yet, but I can confirm my code doesn't involve any OCaml-style Ref cells.

[nodakai]

Just for the record, I had this construct in my code:

data |> flip tap <| fun data -> ....

where flip and tap are from F# Plus.

Replacing flip with a home-grown version fun flip f x y = f y x, defined directly above the calling site, resolved my problem for some unknown reason.
Maybe the bug is related to handling generic functions from external assemblies?

[T-Gro]

The mention of "Specialize" in the message hints me that this is about the usage of generics (or SRTPs) meant to be inlined, but inlining did not happen.

Definitely this does help to narrow it down - also meaning that a standalone repro is likely impossible, and this will only occur on cross-assembly boundaries with optimizations (which are supposed to inline function calls across the boundary).,