F# Regressions affecting F#+

Start by compiling the named docsrc examples with F# 9, then inspect Extensions/Observable.fs and Extensions/AsyncEnumerable.fs for the reported failures. Check the remaining examples and the Tests and TypeLevel projects; done means producing a complete, reproducible inventory of F# 9 regressions.

With the release of F# 9, lot of regressions are being observed.

The idea is to compile a list as much detailed as possible.

• F#+ doesn't compiler anymore:

  • Errors in Extensions/Observable.fs and Extensions/AsyncEnumerable.fs related to SeqT.lisft see below more examples of this error.

• F#+ examples broken:

  • CEs: https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/computation-expressions.fsx#L120-L127
    Fails both when using F#+ nuget and when using F#+ compiled with F#9.
    More information: The for method of the monad.fx builder is compiled as follow:

    in F#9 comp F#+ ==> Monad<unit> For$W[a,T,Monad<unit>](FSharpFunc`2[FSharpFunc`2[Unit,Monad<unit>],Monad<unit>], FSharpFunc`2[Delay,FSharpFunc`2[FSharpFunc`2[Unit,Monad<unit>],FSharpFunc`2[Delay,Monad<unit>]]], FSharpFunc`2[Monad<unit>,FSharpFunc`2[Return,FSharpFunc`2[Unit,Monad<unit>]]], FSharpFunc`2[IDisposable,FSharpFunc`2[FSharpFunc`2[IDisposable,Monad<unit>],FSharpFunc`2[Using,Monad<unit>]]], FSharpFunc`2[Monad<unit>,FSharpFunc`2[FSharpFunc`2[Unit,Monad<unit>],Monad<unit>]], a, FSharpFunc`2[T,Monad<unit>])|];
    
    in existing F#+ ==> Monad<unit> For$W[a,T,Monad<unit>](FSharpFunc`2                                                          [Delay,FSharpFunc`2[FSharpFunc`2[Unit,Monad<unit>],FSharpFunc`2[Delay,Monad<unit>]]], FSharpFunc`2[Monad<unit>,FSharpFunc`2[Return,FSharpFunc`2[Unit,Monad<unit>]]], FSharpFunc`2[IDisposable,FSharpFunc`2[FSharpFunc`2[IDisposable,Monad<unit>],FSharpFunc`2[Using,Monad<unit>]]], FSharpFunc`2[Monad<unit>,FSharpFunc`2[FSharpFunc`2[Unit,Monad<unit>],Monad<unit>]], a, FSharpFunc`2[T,Monad<unit>])|];
    

  • SeqT: https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/type-seqt.fsx#L70-L77
    Fails with `type-seqt.fsx(74,61): error FS0001: 'SeqT_V2.SeqT.lift' does not support the type 'Async', because the latter lacks the required (real or built-in) member 'Map'``

    Same failure in https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/type-seqt.fsx#L147

  • Alternatives:

    • https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-alternative.fsx#L114
      Using F#+ compiled with F#9 -> abstraction-alternative.fsx(114,24): error FS0001: The type 'string option list' does not support the operator 'choice'
    • https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-alternative.fsx#L128
      abstraction-alternative.fsx(128,22): error FS0071: Type constraint mismatch when applying the default type 'obj' for a type inference variable. None of the types 'Async<(string list -> string list)>, obj' support the operator '<*>' Consider adding further type constraints

  • Bitraversable: https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-bitraversable.fsx#L87 abstraction-bitraversable.fsx(87,37): error FS0043: No overloads match for method 'Bisequence'.

  • Misc: https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-misc.fsx#L47
    abstraction-misc.fsx(47,22): error FS0001: '.Choice' does not support the type 'Result<int,string>', because the latter lacks the required (real or built-in) member 'IsAltLeftZero' (seems to be the same as the one in Alternatives.

  • Monad: https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-monad.fsx#L346 (same as above)
    abstraction-monad.fsx(346,16): error FS0001: The type ''a list' does not support the operator 'choice'

  • Profunctor: https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-traversable.fsx#L110-L113

    • https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-profunctor.fsx#L107

      abstraction-profunctor.fsx(107,12): error FS0071: Type constraint mismatch when applying the default type 'obj' for a type inference variable. No overloads match for method 'Map'.

    • https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-profunctor.fsx#L109
      `abstraction-profunctor.fsx(109,12): error FS0071: Type constraint mismatch when applying the default type 'obj' for a type inference variable. No overloads match for method 'Dimap'.

  • Traversable: https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-traversable.fsx#L110-L113
    abstraction-traversable.fsx(110,23): error FS0071: Type constraint mismatch when applying the default type 'obj' for a type inference variable. None of the types '(int list -> int list) list, obj' support the operator '<*>' Consider adding further type constraints

    abstraction-traversable.fsx(111,23): error FS0071: Type constraint mismatch when applying the default type 'obj' for a type inference variable. None of the types '(int list -> int list) option, obj' support the operator '<*>' Consider adding further type constraints

    abstraction-traversable.fsx(112,23): error FS0071: Type constraint mismatch when applying the default type 'obj' for a type inference variable. None of the types '(int list -> int list) list, obj' support the operator '<*>' Consider adding further type constraints

    abstraction-traversable.fsx(113,23): error FS0071: Type constraint mismatch when applying the default type 'obj' for a type inference variable. None of the types '(int list -> int list) list, obj' support the operator '<*>' Consider adding further type constraints

  • ZipApplicative: https://github.com/fsprojects/FSharpPlus/blob/1f0fc122269f5f0a114b8c1d19e3369daf61b0bd/docsrc/content/abstraction-zipapplicative.fsx#L139

    abstraction-zipapplicative.fsx(139,65): error FS0193: None of the types 'Async<int>, Async<char>, Async<'a>' support the operator 'Zip'

Testing is not complete. More errors are expected in Tests and maybe in the TypeLevel project