`edit` producing malformed code according to the LSP (code included)

[kylegoetz]

add

RangedFloat.decoder : Optional Float -> Optional Float -> '{Decoder} Float
RangedFloat.decoder min max = do match value! with
    Unparsed a -> Float.fromText a |> Optional.filter (range min max) |> cases
        None -> Decoder.fail ("Expected value in range.")
        Some a -> a
    _ -> Decoder.fail "Expected number"

and then edit RangedFloat.decoder to get back

RangedFloat.decoder : Optional Float -> Optional Float -> '{Decoder} Float
RangedFloat.decoder min max = use Decoder fail -- <-- LSP reports "I expected a block after this (in red), but there wasn't one ...
do
  match value! with
    Unparsed a ->
      Float.fromText a |> Optional.filter (range min max) |> (cases
        None   -> fail "Expected value in range."
        Some a -> a)
    _          -> fail "Expected number"

If I edit the edit-produced code to:

RangedFloat.decoder : Optional Float -> Optional Float -> '{Decoder} Float
RangedFloat.decoder min max = do
  match value! with
    Unparsed a ->
      Float.fromText a |> Optional.filter (range min max) |> (cases
        None   -> fail "Expected value in range."
        Some a -> a)
    _          -> fail "Expected number"

The problem goes away.

[pchiusano]

Possibly a dupe of https://github.com/unisonweb/unison/issues/4344 but I'll leave it open.

[sellout]

I tried to replicate this, but had to water it down a little (range isn’t something I could find). You can see in this transcript output that use Decoder fail is no longer in the output, but I’m not sure if that means it’s fixed or if I just couldn’t match the code path you hit.

If you still manage to trigger this behavior, please add another example – or let me know if you can get my transcript to trigger it for you.

transcript output

scratch/main> lib.install @unison/json

  Downloaded 14452 entities.

  I installed @unison/json/releases/1.2.3 as unison_json_1_2_3.

RangedFloat.decoder : Float -> Float -> '{Decoder} Float
RangedFloat.decoder min max = do match value! with
    Unparsed a -> Float.fromText a |> Optional.filter (x -> x < max) |> cases
        None -> Decoder.fail ("Expected value in range.")
        Some a -> a
    _ -> Decoder.fail "Expected number"

  Loading changes detected in scratch.u.

  I found and typechecked these definitions in scratch.u. If you
  do an `add` or `update`, here's how your codebase would
  change:
  
    ⍟ These new definitions are ok to `add`:
    
      RangedFloat.decoder : Float -> Float -> '{Decoder} Float

scratch/main> add

  ⍟ I've added these definitions:
  
    RangedFloat.decoder : Float -> Float -> '{Decoder} Float

scratch/main> edit RangedFloat.decoder

  ☝️
  
  I added 1 definitions to the top of scratch.u
  
  You can edit them there, then run `update` to replace the
  definitions currently in this namespace.

scratch/main> load

  Loading changes detected in scratch.u.

  I found and typechecked the definitions in scratch.u. This
  file has been previously added to the codebase.

RangedFloat.decoder : Float -> Float -> '{Decoder} Float
RangedFloat.decoder min max = do match value! with
  Unparsed a ->
    Float.fromText a |> Optional.filter (x -> x Universal.< max) |> (cases
      None   -> Decoder.fail "Expected value in range."
      Some a -> a)
  _          -> Decoder.fail "Expected number"