The children iterators stop at Term::Def variants

[developedby]

Reproducing the behavior

Term::children and this family of function is not returning the next term in the case of a Term::Def.

This is how it's currently defined

  pub fn children(&self) -> impl DoubleEndedIterator<Item = &Term> + Clone {
    multi_iterator!(ChildrenIter { Zero, One, Two, Vec, Mat, Swt, Bend, Fold });
    match self {
      Term::Mat { arg, bnd: _, with_bnd: _, with_arg, arms } => {
        ChildrenIter::Mat([arg.as_ref()].into_iter().chain(with_arg.iter()).chain(arms.iter().map(|r| &r.2)))
      }
      Term::Swt { arg, bnd: _, with_bnd: _, with_arg, pred: _, arms } => {
        ChildrenIter::Swt([arg.as_ref()].into_iter().chain(with_arg.iter()).chain(arms))
      }
      Term::Bend { bnd: _, arg: init, cond, step, base } => {
        ChildrenIter::Bend(init.iter().chain([cond.as_ref(), step.as_ref(), base.as_ref()]))
      }
      Term::Fold { bnd: _, arg, with_bnd: _, with_arg, arms } => {
        ChildrenIter::Fold([arg.as_ref()].into_iter().chain(with_arg.iter()).chain(arms.iter().map(|r| &r.2)))
      }
      Term::Fan { els, .. } | Term::List { els } => ChildrenIter::Vec(els),
      Term::Let { val: fst, nxt: snd, .. }
      | Term::Ask { val: fst, nxt: snd, .. }
      | Term::Use { val: fst, nxt: snd, .. }
      | Term::App { fun: fst, arg: snd, .. }
      | Term::Oper { fst, snd, .. } => ChildrenIter::Two([fst.as_ref(), snd.as_ref()]),
      Term::Lam { bod, .. } | Term::With { bod, .. } | Term::Open { bod, .. } => {
        ChildrenIter::One([bod.as_ref()])
      }
      Term::Var { .. }
      | Term::Link { .. }
      | Term::Num { .. }
      | Term::Nat { .. }
      | Term::Str { .. }
      | Term::Ref { .. }
      | Term::Def { .. }
      | Term::Era
      | Term::Err => ChildrenIter::Zero([]),
    }
  }

The Term::Def case should instead be Term::Def { nxt, .. } => ChildrenIter::One([nxt]).

This will cause the passes to stop at local function definitions and ignore the subtrees in the AST in this csae.

This will create some bugs in the compilation, although I don't currently have any concrete example.

System Settings

Bend commit 45839a7

Additional context

No response