Wrongful "update" prompt / EffectConstructorHadMultipleEffects

[Baccata]

Describe and demonstrate the bug

On a codebase that compiled correctly, pulling some functions in the scratch file leads UCM to prompt me to update, without having made any modifications to the function in question. Additionally, once I do attempt to update, the compiler fails to typecheck, with some cryptic error about ability constructors having multiple effects (when in fact it's just a polymorphic ability that has a higher-kinded type parameter)

.> clone @baccata/schemas/@baccata/multiple-effects-repro
.> edit Schematic

Then save the file without touching it : UCM prompts me to update the terms, despite them having received no changes :

  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 names already exist. You can `update` them to your new definition:
    
      type schemas.Alts u a
      type schemas.Fields s a
      type schemas.Schema a
      ability schemas.abilities.AltSchematic f r u
      ability schemas.abilities.FieldSchematic f s
      ability schemas.abilities.Schematic f

After that, run the update command.

.> update 

UCM then fails typechecking :

  Loading changes detected in ~/scratch.u.

  EffectConstructorHadMultipleEffects:
    {CompileTime f1569, CompileTime f1569} (Eval (f1569 a1568))

I can then fix the typechecking error by removing the ability ascription on the RHS of handling functions :

Doing this everywhere until I don't get typechecking errors reverts to the original state of the codebase.

Environment (please complete the following information):

• release/0.5.27
• macOS 14.5, ARM 64
• vscode Unison extension v1.2.0