Capturing bind with symbolic name doesn't work in ability constructor match

[ceedubs]

Describe and demonstrate the bug

fresh/main> builtins.merge

  Done.

In the following code, the user-provided function can be captured as == by using parentheses (==):

ensureEqBy : (a -> a -> Boolean) -> a -> a -> ()
ensureEqBy (==) a1 a2 = if a1 == a2 then () else bug ("not equal", a1, a2)

ability EnsureEq where
  ensureEqBy2 : (a -> a -> Boolean) -> a -> a -> ()

  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`:
    
      ability EnsureEq
      ensureEqBy : (a ->{g1} a ->{g} Boolean)
                   -> a
                   -> a
                   ->{g1, g} ()

However, the same does not work in an ability constructor match:

EnsureEq.run : '{g, EnsureEq} r -> {g} r
EnsureEq.run =
  go thunk = handle !thunk with cases
    { r } -> r
    { ensureEqBy2 (==) a1 a2 -> k } ->
      if a1 == a2 then () else bug ("not equal", a1, a2)
      go k
  go

🛑

The transcript failed due to an error in the stanza above. The error is:

I got confused here:

    5 |     { ensureEqBy2 (==) a1 a2 -> k } ->


I was surprised to find a ( here.
I was expecting one of these instead:

* @

Environment (please complete the following information):

• ucm --version bc7e65d built on 04/22/2025