Omitting `update` in Mutable class fails to err under separation checking

[rjolly]

Compiler version

3.8.0-RC1-bin-20251017-96aff06-NIGHTLY

Context

Experimenting with https://nightly.scala-lang.org/docs/reference/experimental/capture-checking/separation-checking.html

Minimized code

import language.experimental.{captureChecking, separationChecking}

class Ref(init: Int) extends scala.caps.Mutable:
  private var current = init
  def get: Int = current
  update def set(x: Int): Unit = current = x // no error if `update` is omitted

[rjolly]

This is fixed in 3.8.0-RC1-bin-20251024-41d321d-NIGHTLY (probably by #24205 ). So, closing.

  def set(x: Int): Unit = current = x
                          ^^^^^^^^^^^
       Cannot assign to field current of Ref.this
       since the access is in method set, which is not an update method.