I was naively expecting that 'from the end slicing and indexing' would be moved from F#5 Preview to F#6.

But when trying out the following code (taken from F# RFC FS-1076) produces a compiler error when using F# 6.

let list = [1;2;3;4;5]

list.[..^0]   // 1,2,3,4,5
list.[..^1]   // 1,2,3,4
list.[0..^1]  // 1,2,3,4
list.[^1..]   // 4,5
list.[^0..]   // 5
list.[^2..^1] // 3,4

Compiler error:
"From the end slicing with requires language version 5.0, use /langversion:preview."

I've since learned that this is not yet included in F#6, but it is still in the preview of the language, so I think this should be changed to:
"From the end slicing with requires language version 6.0, use /langversion:preview."

Provide the steps required to reproduce the problem:

Either use your IDE to get error feedback or run dotnet build to view the errors

If possible attach a zip file with the repro case. This often makes it easier for others to reproduce.
The zip file should ideally represent the situation just before the call/step that is problematic.

Expected behavior

Error should be:
"From the end slicing with requires language version 6.0, use /langversion:preview."

Actual behavior

Compiler error:
From the end slicing with requires language version 5.0, use /langversion:preview.

Known workarounds

You can still set <LangVersion>preview</LangVersion> but the error is slightly misleading.

Related information

Provide any related information (optional):

• Operating system

• .NET Runtime kind (.NET Core, .NET Framework, Mono)
  .NET 6

• Editing Tools (e.g. Visual Studio Version, Visual Studio)
  Visual Studio Code