[Rename Refactoring] Rename doesn't work correctly with Active Patterns

[dungpa]

Example:

let (|Float|_|) (str: string) =
   let mutable floatvalue = 0.0
   if System.Double.TryParse(str, &floatvalue) then Some(floatvalue)
   else None

let parseNumeric str =
   match str with
   | Integer i -> printfn "%d : Integer" i
   | Float f -> printfn "%f : Floating point" f
   | _ -> printfn "%s : Not matched." str

Renaming the use of Float to Float2 resulting:

let (|Float2) (str: string) =
     let mutable floatvalue = 0.0
     if System.Double.TryParse(str, &floatvalue) then Some(floatvalue)
     else None

that doesn't compile.

Additionally:

• Rename dialog doesn't prevent me to use lowercase identifiders (e.g. float2)
• Users CAN'T rename definition of Float in (|Float|_|)

This might include a bug in FSharp.Compiler.Service which should be reported upstream.

[ghost]

Yes, again this is an FCS bug/limitation. Please report upstream, and ideally add a failing test case to FCS

[ghost]

The underlying problem is fixed in FCS 0.0.26.

However your mileage may vary, particularly when renaming within an active pattern definition let (|AAA|BBB|) x = ..., as it depends on how your identifier-cracking works - does it treat a cursor location of AAA as the idenitifier AAA or the compund identifier representing the overall function.

Renaming at other locations should work OK

[dungpa]

Have you tried the failing tests in fsharp/fsharp-compiler-docs#62? It's the way I fancy it (renaming only individual identifiers).

[ghost]

Yes, the added tests were great ad pass (not the exception ones). A modified copy of them was included.

[dungpa]

@dsyme Is there any easy to check whether a symbol is active pattern? https://github.com/fsharp/FSharp.Compiler.Service/blob/master/src/fsharp/vs/Typed.fs#L758 doesn't seem to help.

[ghost]

That property should work for an active pattern function (|A|B|) (i.e. the symbol for the active pattern function)

But I think you want to test whether a symbol is an active pattern label (like A)? I don't think there is a way to do that, at least just yet. We probably need a subtype of FSharpSymbol called FSharpActivePatternLabel - it's somewhat of a special case.

Also there is no way to retrieve the FSharpActivePatternLabels for a active pattern function. We should add that. Add an FCS issue, thanks