FS0073 internal error when compiling an exception type with a property with an explicit getter

[chrisvanderpennen]

This appears to be a regression between core sdk 6.0.302 and 6.0.400 on Linux. The following builds with sdk 6.0.302:

 exception CustomException of details: string
     with
         member self.Details with get (): string = self.details

On 6.0.400, it fails with the following error:

❯ cat test.fsx
 exception CustomException of details: string
     with
         member self.Details with get (): string = self.details
❯ dotnet fsi test.fsx


/home/chrisv/code/test.fsx(3,10): error FS0073: internal error: Unexpected definition (GetSetMember
   (Some
      (SynBinding
         (None, Normal, false, false, [],
          PreXmlMerge
  (PreXmlDoc ((3,9), FSharp.Compiler.Xml.XmlDocCollector), PreXmlDocEmpty),
          SynValData
            (Some
               { IsInstance = true
                 IsDispatchSlot = false
                 IsOverrideOrExplicitImpl = false
                 IsFinal = false
                 MemberKind = PropertyGet
                 Trivia =
                  { MemberRange = Some /home/chrisv/code/test.fsx (3,9--3,15)
                    OverrideRange = None
                    AbstractRange = None
                    StaticRange = None
                    DefaultRange = None } },
             SynValInfo
               ([[SynArgInfo ([], false, None)]; []],
                SynArgInfo ([], false, None)), None),
          LongIdent
            (SynLongIdent
               ([self; Details], [/home/chrisv/code/test.fsx (3,20--3,21)],
                [None; None]), Some get, None,
             Pats
               [Paren
                  (Const (Unit, /home/chrisv/code/test.fsx (3,38--3,40)),
                   /home/chrisv/code/test.fsx (3,38--3,40))], None,
             /home/chrisv/code/test.fsx (3,34--3,40)),
          Some
            (SynBindingReturnInfo
               (LongIdent (SynLongIdent ([string], [], [None])),
                /home/chrisv/code/test.fsx (3,42--3,48), [])),
          Typed
            (LongIdent
               (false,
                SynLongIdent
                  ([self; details], [/home/chrisv/code/test.fsx (3,55--3,56)],
                   [None; None]), None, /home/chrisv/code/test.fsx (3,51--3,63)),
             LongIdent (SynLongIdent ([string], [], [None])),
             /home/chrisv/code/test.fsx (3,51--3,63)),
          /home/chrisv/code/test.fsx (3,34--3,40), NoneAtInvisible,
          { LetKeyword = None
            EqualsRange = Some /home/chrisv/code/test.fsx (3,49--3,50) })), None,
    /home/chrisv/code/test.fsx (3,9--3,63),
    { WithKeyword = /home/chrisv/code/test.fsx (3,29--3,33)
      GetKeyword = Some /home/chrisv/code/test.fsx (3,34--3,37)
      AndKeyword = None
      SetKeyword = None }),
 ContainerInfo
  (Parent FSI_0001,
   Some
     (MemberOrValContainerInfo (CustomException, None, None, NoSafeInitInfo, []))))

This also fails when added to Program.fs from dotnet new console --language f#.

Known workarounds

Removing the explicit getter declaration prevents the issue from being encountered:

exception CustomException of details: string with
    member self.Details: string = self.details

Related information

❯ dotnet fsi --version
Microsoft (R) F# Interactive version 12.0.4.0 for F# 6.0
❯ dotnet --list-sdks
6.0.400 [/usr/share/dotnet/sdk]
❯ uname -a
Linux redacted 5.15.57.1-microsoft-standard-WSL2 #1 SMP Wed Jul 27 02:20:31 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
❯ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.4 LTS
Release:        20.04
Codename:       focal

I have git bisect running to try and narrow this down, I'll update when it completes.

[vzarytovskii]

@nojaf does this ring a bell to you by any chance?
I remember you were doing something around getters/setters?

Update: #13435 and #13420

[nojaf]

Yes, let me take a look at that.

[chrisvanderpennen]

Appreciate the fast fix! <3