message: Parameterize Reservation by AValue
  Summary:
  `AValueDyn` is not meant to be used as type parameter.
  Code cleanup.
diff: @@ -131,12 +131,12 @@ impl AValueForward {
  /// Reservation is morally a Reservation<T>, but we treat is as an
  /// existential.
  /// Tied to the lifetime of the heap.
  -pub(crate) struct Reservation<'v, 'v2, T: AValueDyn<'v2>> {
  +pub(crate) struct Reservation<'v, 'v2, T: AValue<'v2>> {
  pointer: *mut AValueRepr<T>, // Secretly AValueObject<T>
  phantom: PhantomData<(&'v (), &'v2 T)>,
  }
  -impl<'v, 'v2, T: AValueDyn<'v2>> Reservation<'v, 'v2, T> {
  +impl<'v, 'v2, T: AValue<'v2>> Reservation<'v, 'v2, T> {
  pub(crate) fn fill(self, x: T) {
  unsafe {
  ptr::write(
  