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WIP partial apply fix

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This commit is contained in:
jackh726 2021-07-13 10:50:40 -04:00
parent c63f1fe92b
commit a9f1e1c440
2 changed files with 192 additions and 103 deletions
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266
compiler/rustc_trait_selection/src/traits/project.rs
View file

@ -298,6 +298,7 @@ struct AssocTypeNormalizer<'a, 'b, 'tcx> {
cause: ObligationCause<'tcx>,
obligations: &'a mut Vec<PredicateObligation<'tcx>>,
depth: usize,
universes: Vec<Option<ty::UniverseIndex>>,
}
impl<'a, 'b, 'tcx> AssocTypeNormalizer<'a, 'b, 'tcx> {
@ -308,12 +309,16 @@ impl<'a, 'b, 'tcx> AssocTypeNormalizer<'a, 'b, 'tcx> {
depth: usize,
obligations: &'a mut Vec<PredicateObligation<'tcx>>,
) -> AssocTypeNormalizer<'a, 'b, 'tcx> {
AssocTypeNormalizer { selcx, param_env, cause, obligations, depth }
AssocTypeNormalizer { selcx, param_env, cause, obligations, depth, universes: vec![] }
}
fn fold<T: TypeFoldable<'tcx>>(&mut self, value: T) -> T {
let value = self.selcx.infcx().resolve_vars_if_possible(value);
if value.has_escaping_bound_vars() {
bug!("Normalizing without wrapping in a `Binder`");
}
if !value.has_projections() { value } else { value.fold_with(self) }
}
}
@ -323,6 +328,16 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
self.selcx.tcx()
}
fn fold_binder<T: TypeFoldable<'tcx>>(
&mut self,
t: ty::Binder<'tcx, T>,
) -> ty::Binder<'tcx, T> {
self.universes.push(None);
let t = t.super_fold_with(self);
self.universes.pop();
t
}
fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
if !ty.has_projections() {
return ty;
@ -412,37 +427,40 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
// give up and fall back to pretending like we never tried!
let infcx = self.selcx.infcx();
let (data, mapped_regions, mapped_types, mapped_consts, universe_map) =
BoundVarReplacer::replace_bound_vars(infcx, data);
let replaced =
BoundVarReplacer::replace_bound_vars(infcx, &mut self.universes, data);
if let Some((data, mapped_regions, mapped_types, mapped_consts)) = replaced {
let normalized_ty = opt_normalize_projection_type(
self.selcx,
self.param_env,
data,
self.cause.clone(),
self.depth,
&mut self.obligations,
)
.ok()
.flatten()
.unwrap_or_else(|| ty);
let normalized_ty = opt_normalize_projection_type(
self.selcx,
self.param_env,
data,
self.cause.clone(),
self.depth,
&mut self.obligations,
)
.ok()
.flatten()
.unwrap_or_else(|| ty);
let normalized_ty = PlaceholderReplacer::replace_placeholders(
infcx,
mapped_regions,
mapped_types,
mapped_consts,
universe_map,
normalized_ty,
);
debug!(
?self.depth,
?ty,
?normalized_ty,
obligations.len = ?self.obligations.len(),
"AssocTypeNormalizer: normalized type"
);
normalized_ty
let normalized_ty = PlaceholderReplacer::replace_placeholders(
infcx,
mapped_regions,
mapped_types,
mapped_consts,
&self.universes,
normalized_ty,
);
debug!(
?self.depth,
?ty,
?normalized_ty,
obligations.len = ?self.obligations.len(),
"AssocTypeNormalizer: normalized type"
);
normalized_ty
} else {
ty
}
}
_ => ty,
@ -460,26 +478,42 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
}
pub struct BoundVarReplacer<'me, 'tcx> {
pub infcx: &'me InferCtxt<'me, 'tcx>,
pub mapped_regions: BTreeMap<ty::PlaceholderRegion, ty::BoundRegion>,
pub mapped_types: BTreeMap<ty::PlaceholderType, ty::BoundTy>,
pub mapped_consts: BTreeMap<ty::PlaceholderConst<'tcx>, ty::BoundVar>,
pub universes: BTreeMap<ty::DebruijnIndex, ty::UniverseIndex>,
pub universes_inverse: BTreeMap<ty::UniverseIndex, ty::DebruijnIndex>,
pub current_index: ty::DebruijnIndex,
infcx: &'me InferCtxt<'me, 'tcx>,
// These three maps track the bound variable that were replaced by placeholders. It might be
// nice to remove these since we already have the `kind` in the placeholder; we really just need
// the `var` (but we *could* bring that into scope if we were to track them as we pass them).
mapped_regions: BTreeMap<ty::PlaceholderRegion, ty::BoundRegion>,
mapped_types: BTreeMap<ty::PlaceholderType, ty::BoundTy>,
mapped_consts: BTreeMap<ty::PlaceholderConst<'tcx>, ty::BoundVar>,
// The current depth relative to *this* folding, *not* the entire normalization. In other words,
// the depth of binders we've passed here.
current_index: ty::DebruijnIndex,
// The `UniverseIndex` of the binding levels above us. These are optional, since we are lazy:
// we don't actually create a universe until we see a bound var we have to replace.
universe_indices: &'me mut Vec<Option<ty::UniverseIndex>>,
// FIXME: So, this is a less-than-ideal solution to a problem we want to solve eventually. Ideally, we
// shouldn't need to worry about bound vars for which we haven't passed (`self.current_index`)
// or that we don't explicitly know about (`self.universe_indices`). This is true for
// `AssocTypeNormalizer` but not `QueryNormalizer` currently. When we can always know about
// any binding levels above us, we can remove this. (The alternative would be
// `outer_exclusive_binder`, but that only exists on `Ty`. Otherwise, we would have to visit
// through the `T`, which we specifically want to avoid not being lazy.)
failed: bool,
}
impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> {
/// Returns `Some` if we *were* able to replace bound vars. If there are any bound vars that
/// use a binding level above `universe_indices.len()`, we fail.
pub fn replace_bound_vars<T: TypeFoldable<'tcx>>(
infcx: &'me InferCtxt<'me, 'tcx>,
universe_indices: &'me mut Vec<Option<ty::UniverseIndex>>,
value: T,
) -> (
) -> Option<(
T,
BTreeMap<ty::PlaceholderRegion, ty::BoundRegion>,
BTreeMap<ty::PlaceholderType, ty::BoundTy>,
BTreeMap<ty::PlaceholderConst<'tcx>, ty::BoundVar>,
BTreeMap<ty::UniverseIndex, ty::DebruijnIndex>,
) {
)> {
let mapped_regions: BTreeMap<ty::PlaceholderRegion, ty::BoundRegion> = BTreeMap::new();
let mapped_types: BTreeMap<ty::PlaceholderType, ty::BoundTy> = BTreeMap::new();
let mapped_consts: BTreeMap<ty::PlaceholderConst<'tcx>, ty::BoundVar> = BTreeMap::new();
@ -489,20 +523,16 @@ impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> {
mapped_regions,
mapped_types,
mapped_consts,
universes: BTreeMap::new(),
universes_inverse: BTreeMap::new(),
current_index: ty::INNERMOST,
universe_indices,
failed: false,
};
let value = value.super_fold_with(&mut replacer);
(
value,
replacer.mapped_regions,
replacer.mapped_types,
replacer.mapped_consts,
replacer.universes_inverse,
)
(!replacer.failed).then(|| {
(value, replacer.mapped_regions, replacer.mapped_types, replacer.mapped_consts)
})
}
}
@ -523,15 +553,24 @@ impl TypeFolder<'tcx> for BoundVarReplacer<'_, 'tcx> {
fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
match *r {
ty::ReLateBound(debruijn, br) => {
ty::ReLateBound(debruijn, _)
if debruijn.as_usize() + 1
> self.current_index.as_usize() + self.universe_indices.len() =>
{
self.failed = true;
r
}
ty::ReLateBound(debruijn, br) if debruijn >= self.current_index => {
let infcx = self.infcx;
let placeholder_db_index =
ty::DebruijnIndex::from_u32(self.current_index.as_u32() - debruijn.as_u32());
let universe = *self
.universes
.entry(placeholder_db_index)
.or_insert_with(|| infcx.create_next_universe());
self.universes_inverse.insert(universe, placeholder_db_index);
let index = self.universe_indices.len() - debruijn.as_usize()
+ self.current_index.as_usize()
- 1;
let universe = self.universe_indices[index].unwrap_or_else(|| {
for i in self.universe_indices.iter_mut().take(index + 1) {
*i = i.or_else(|| Some(infcx.create_next_universe()))
}
self.universe_indices[index].unwrap()
});
let p = ty::PlaceholderRegion { universe, name: br.kind };
self.mapped_regions.insert(p.clone(), br);
self.infcx.tcx.mk_region(ty::RePlaceholder(p))
@ -542,15 +581,24 @@ impl TypeFolder<'tcx> for BoundVarReplacer<'_, 'tcx> {
fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
match *t.kind() {
ty::Bound(debruijn, bound_ty) => {
ty::Bound(debruijn, _)
if debruijn.as_usize() + 1
> self.current_index.as_usize() + self.universe_indices.len() =>
{
self.failed = true;
t
}
ty::Bound(debruijn, bound_ty) if debruijn >= self.current_index => {
let infcx = self.infcx;
let placeholder_db_index =
ty::DebruijnIndex::from_u32(self.current_index.as_u32() - debruijn.as_u32());
let universe = *self
.universes
.entry(placeholder_db_index)
.or_insert_with(|| infcx.create_next_universe());
self.universes_inverse.insert(universe, placeholder_db_index);
let index = self.universe_indices.len() - debruijn.as_usize()
+ self.current_index.as_usize()
- 1;
let universe = self.universe_indices[index].unwrap_or_else(|| {
for i in self.universe_indices.iter_mut().take(index + 1) {
*i = i.or_else(|| Some(infcx.create_next_universe()))
}
self.universe_indices[index].unwrap()
});
let p = ty::PlaceholderType { universe, name: bound_ty.var };
self.mapped_types.insert(p.clone(), bound_ty);
self.infcx.tcx.mk_ty(ty::Placeholder(p))
@ -562,15 +610,26 @@ impl 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, bound_const), ty } => {
ty::Const { val: ty::ConstKind::Bound(debruijn, _), ty: _ }
if debruijn.as_usize() + 1
> self.current_index.as_usize() + self.universe_indices.len() =>
{
self.failed = true;
ct
}
ty::Const { val: ty::ConstKind::Bound(debruijn, bound_const), ty }
if debruijn >= self.current_index =>
{
let infcx = self.infcx;
let placeholder_db_index =
ty::DebruijnIndex::from_u32(self.current_index.as_u32() - debruijn.as_u32());
let universe = *self
.universes
.entry(placeholder_db_index)
.or_insert_with(|| infcx.create_next_universe());
self.universes_inverse.insert(universe, placeholder_db_index);
let index = self.universe_indices.len() - debruijn.as_usize()
+ self.current_index.as_usize()
- 1;
let universe = self.universe_indices[index].unwrap_or_else(|| {
for i in self.universe_indices.iter_mut().take(index + 1) {
*i = i.or_else(|| Some(infcx.create_next_universe()))
}
self.universe_indices[index].unwrap()
});
let p = ty::PlaceholderConst {
universe,
name: ty::BoundConst { var: bound_const, ty },
@ -584,13 +643,14 @@ impl TypeFolder<'tcx> for BoundVarReplacer<'_, 'tcx> {
}
}
// The inverse of `BoundVarReplacer`: replaces placeholders with the bound vars from which they came.
pub struct PlaceholderReplacer<'me, 'tcx> {
pub infcx: &'me InferCtxt<'me, 'tcx>,
pub mapped_regions: BTreeMap<ty::PlaceholderRegion, ty::BoundRegion>,
pub mapped_types: BTreeMap<ty::PlaceholderType, ty::BoundTy>,
pub mapped_consts: BTreeMap<ty::PlaceholderConst<'tcx>, ty::BoundVar>,
pub universes_inverse: BTreeMap<ty::UniverseIndex, ty::DebruijnIndex>,
pub current_index: ty::DebruijnIndex,
infcx: &'me InferCtxt<'me, 'tcx>,
mapped_regions: BTreeMap<ty::PlaceholderRegion, ty::BoundRegion>,
mapped_types: BTreeMap<ty::PlaceholderType, ty::BoundTy>,
mapped_consts: BTreeMap<ty::PlaceholderConst<'tcx>, ty::BoundVar>,
universe_indices: &'me Vec<Option<ty::UniverseIndex>>,
current_index: ty::DebruijnIndex,
}
impl<'me, 'tcx> PlaceholderReplacer<'me, 'tcx> {
@ -599,7 +659,7 @@ impl<'me, 'tcx> PlaceholderReplacer<'me, 'tcx> {
mapped_regions: BTreeMap<ty::PlaceholderRegion, ty::BoundRegion>,
mapped_types: BTreeMap<ty::PlaceholderType, ty::BoundTy>,
mapped_consts: BTreeMap<ty::PlaceholderConst<'tcx>, ty::BoundVar>,
universes_inverse: BTreeMap<ty::UniverseIndex, ty::DebruijnIndex>,
universe_indices: &'me Vec<Option<ty::UniverseIndex>>,
value: T,
) -> T {
let mut replacer = PlaceholderReplacer {
@ -607,7 +667,7 @@ impl<'me, 'tcx> PlaceholderReplacer<'me, 'tcx> {
mapped_regions,
mapped_types,
mapped_consts,
universes_inverse,
universe_indices,
current_index: ty::INNERMOST,
};
value.super_fold_with(&mut replacer)
@ -648,13 +708,15 @@ impl TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> {
let replace_var = self.mapped_regions.get(&p);
match replace_var {
Some(replace_var) => {
let db = self
.universes_inverse
.get(&p.universe)
let index = self
.universe_indices
.iter()
.position(|u| matches!(u, Some(pu) if *pu == p.universe))
.unwrap_or_else(|| bug!("Unexpected placeholder universe."));
let index =
ty::DebruijnIndex::from_u32(db.as_u32() + self.current_index.as_u32());
self.tcx().mk_region(ty::ReLateBound(index, *replace_var))
let db = ty::DebruijnIndex::from_usize(
self.universe_indices.len() - index + self.current_index.as_usize() - 1,
);
self.tcx().mk_region(ty::ReLateBound(db, *replace_var))
}
None => r1,
}
@ -673,13 +735,15 @@ impl TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> {
let replace_var = self.mapped_types.get(&p);
match replace_var {
Some(replace_var) => {
let db = self
.universes_inverse
.get(&p.universe)
let index = self
.universe_indices
.iter()
.position(|u| matches!(u, Some(pu) if *pu == p.universe))
.unwrap_or_else(|| bug!("Unexpected placeholder universe."));
let index =
ty::DebruijnIndex::from_u32(db.as_u32() + self.current_index.as_u32());
self.tcx().mk_ty(ty::Bound(index, *replace_var))
let db = ty::DebruijnIndex::from_usize(
self.universe_indices.len() - index + self.current_index.as_usize() - 1,
);
self.tcx().mk_ty(ty::Bound(db, *replace_var))
}
None => ty,
}
@ -695,14 +759,16 @@ impl TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> {
let replace_var = self.mapped_consts.get(&p);
match replace_var {
Some(replace_var) => {
let db = self
.universes_inverse
.get(&p.universe)
let index = self
.universe_indices
.iter()
.position(|u| matches!(u, Some(pu) if *pu == p.universe))
.unwrap_or_else(|| bug!("Unexpected placeholder universe."));
let index =
ty::DebruijnIndex::from_u32(db.as_u32() + self.current_index.as_u32());
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(index, *replace_var), ty })
.mk_const(ty::Const { val: ty::ConstKind::Bound(db, *replace_var), ty })
}
None => ct,
}

29
compiler/rustc_trait_selection/src/traits/query/normalize.rs
View file

@ -61,6 +61,7 @@ impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> {
error: false,
cache: SsoHashMap::new(),
anon_depth: 0,
universes: vec![],
};
let result = value.fold_with(&mut normalizer);
@ -91,6 +92,7 @@ struct QueryNormalizer<'cx, 'tcx> {
cache: SsoHashMap<Ty<'tcx>, Ty<'tcx>>,
error: bool,
anon_depth: usize,
universes: Vec<Option<ty::UniverseIndex>>,
}
impl<'cx, 'tcx> TypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
@ -98,6 +100,16 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
self.infcx.tcx
}
fn fold_binder<T: TypeFoldable<'tcx>>(
&mut self,
t: ty::Binder<'tcx, T>,
) -> ty::Binder<'tcx, T> {
self.universes.push(None);
let t = t.super_fold_with(self);
self.universes.pop();
t
}
#[instrument(level = "debug", skip(self))]
fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
if !ty.has_projections() {
@ -216,8 +228,19 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
let tcx = self.infcx.tcx;
let infcx = self.infcx;
let (data, mapped_regions, mapped_types, mapped_consts, universe_map) =
crate::traits::project::BoundVarReplacer::replace_bound_vars(infcx, data);
let replaced = crate::traits::project::BoundVarReplacer::replace_bound_vars(
infcx,
&mut self.universes,
data,
);
let (data, mapped_regions, mapped_types, mapped_consts) = match replaced {
Some(r) => r,
None => {
bug!("{:?} {:?}", data, self.universes);
//self.error = true;
//return ty.super_fold_with(self);
}
};
let data = data.super_fold_with(self);
let mut orig_values = OriginalQueryValues::default();
@ -263,7 +286,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
mapped_regions,
mapped_types,
mapped_consts,
universe_map,
&self.universes,
normalized_ty,
)
}