bjoernager/rust
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Overhaul Const.

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Specifically, rename the `Const` struct as `ConstS` and re-introduce `Const` as
this:
```
pub struct Const<'tcx>(&'tcx Interned<ConstS>);
```
This now matches `Ty` and `Predicate` more closely, including using
pointer-based `eq` and `hash`.

Notable changes:
- `mk_const` now takes a `ConstS`.
- `Const` was copy, despite being 48 bytes. Now `ConstS` is not, so need a
  we need separate arena for it, because we can't use the `Dropless` one any
  more.
- Many `&'tcx Const<'tcx>`/`&Const<'tcx>` to `Const<'tcx>` changes
- Many `ct.ty` to `ct.ty()` and `ct.val` to `ct.val()` changes.
- Lots of tedious sigil fiddling.
This commit is contained in:
Nicholas Nethercote 2022-02-02 14:24:45 +11:00
parent 7eb15509ce
commit a95fb8b150
116 changed files with 654 additions and 619 deletions
Download patch file Download diff file Expand all files Collapse all files

30
compiler/rustc_trait_selection/src/traits/project.rs
View file

@ -499,7 +499,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
}
}
fn fold_const(&mut self, constant: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
fn fold_const(&mut self, constant: ty::Const<'tcx>) -> ty::Const<'tcx> {
if self.selcx.tcx().lazy_normalization() {
constant
} else {
@ -622,24 +622,24 @@ impl<'tcx> TypeFolder<'tcx> for BoundVarReplacer<'_, 'tcx> {
}
}
fn fold_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
match *ct {
ty::Const { val: ty::ConstKind::Bound(debruijn, _), ty: _ }
fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> {
match ct.val() {
ty::ConstKind::Bound(debruijn, _)
if debruijn.as_usize() + 1
> self.current_index.as_usize() + self.universe_indices.len() =>
{
bug!("Bound vars outside of `self.universe_indices`");
}
ty::Const { val: ty::ConstKind::Bound(debruijn, bound_const), ty }
if debruijn >= self.current_index =>
{
ty::ConstKind::Bound(debruijn, bound_const) if debruijn >= self.current_index => {
let universe = self.universe_for(debruijn);
let p = ty::PlaceholderConst {
universe,
name: ty::BoundConst { var: bound_const, ty },
name: ty::BoundConst { var: bound_const, ty: ct.ty() },
};
self.mapped_consts.insert(p, bound_const);
self.infcx.tcx.mk_const(ty::Const { val: ty::ConstKind::Placeholder(p), ty })
self.infcx
.tcx
.mk_const(ty::ConstS { val: ty::ConstKind::Placeholder(p), ty: ct.ty() })
}
_ if ct.has_vars_bound_at_or_above(self.current_index) => ct.super_fold_with(self),
_ => ct,
@ -758,8 +758,8 @@ impl<'tcx> TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> {
}
}
fn fold_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
if let ty::Const { val: ty::ConstKind::Placeholder(p), ty } = *ct {
fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> {
if let ty::ConstKind::Placeholder(p) = ct.val() {
let replace_var = self.mapped_consts.get(&p);
match replace_var {
Some(replace_var) => {
@ -771,8 +771,10 @@ impl<'tcx> TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> {
let db = ty::DebruijnIndex::from_usize(
self.universe_indices.len() - index + self.current_index.as_usize() - 1,
);
self.tcx()
.mk_const(ty::Const { val: ty::ConstKind::Bound(db, *replace_var), ty })
self.tcx().mk_const(ty::ConstS {
val: ty::ConstKind::Bound(db, *replace_var),
ty: ct.ty(),
})
}
None => ct,
}
@ -1862,7 +1864,7 @@ fn confirm_impl_candidate<'cx, 'tcx>(
crate::traits::InternalSubsts::identity_for_item(tcx, assoc_ty.item.def_id);
let did = ty::WithOptConstParam::unknown(assoc_ty.item.def_id);
let val = ty::ConstKind::Unevaluated(ty::Unevaluated::new(did, identity_substs));
tcx.mk_const(ty::Const { ty, val }).into()
tcx.mk_const(ty::ConstS { ty, val }).into()
} else {
ty.into()
};