bjoernager/rust
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Auto merge of #96883 - jackh726:early-binder-2, r=oli-obk

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Add EarlyBinder

Chalk has no concept of `Param` (e0ade19d13/chalk-ir/src/lib.rs (L579)) or `ReEarlyBound` (e0ade19d13/chalk-ir/src/lib.rs (L1308)). Everything  is just "bound" - the equivalent of rustc's late-bound. It's not completely clear yet whether to move everything to the same time of binder in rustc or add `Param` and `ReEarlyBound` in Chalk.

Either way, tracking when we have or haven't already substituted out these in rustc can be helpful.

As a first step, I'm just adding a `EarlyBinder` newtype that is required to call `subst`. I also add a couple "transparent" `bound_*` wrappers around a couple query that are often immediately substituted.

r? `@nikomatsakis`
This commit is contained in:
bors 2022-05-14 23:53:11 +00:00
commit 2a8a0fc423
67 changed files with 400 additions and 217 deletions
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20
compiler/rustc_trait_selection/src/traits/select/mod.rs
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@ -38,7 +38,7 @@ use rustc_middle::ty::fold::BottomUpFolder;
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::relate::TypeRelation;
use rustc_middle::ty::subst::{GenericArgKind, Subst, SubstsRef};
use rustc_middle::ty::{self, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
use rustc_middle::ty::{self, EarlyBinder, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable};
use rustc_span::symbol::sym;
@ -1341,7 +1341,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
);
}
};
let bounds = tcx.item_bounds(def_id).subst(tcx, substs);
let bounds = tcx.bound_item_bounds(def_id).subst(tcx, substs);
// The bounds returned by `item_bounds` may contain duplicates after
// normalization, so try to deduplicate when possible to avoid
@ -1795,11 +1795,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
ty::Adt(def, substs) => {
let sized_crit = def.sized_constraint(self.tcx());
// (*) binder moved here
Where(
obligation.predicate.rebind({
sized_crit.iter().map(|ty| ty.subst(self.tcx(), substs)).collect()
}),
)
Where(obligation.predicate.rebind({
sized_crit.iter().map(|ty| EarlyBinder(*ty).subst(self.tcx(), substs)).collect()
}))
}
ty::Projection(_) | ty::Param(_) | ty::Opaque(..) => None,
@ -1962,7 +1960,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// We can resolve the `impl Trait` to its concrete type,
// which enforces a DAG between the functions requiring
// the auto trait bounds in question.
t.rebind(vec![self.tcx().type_of(def_id).subst(self.tcx(), substs)])
t.rebind(vec![self.tcx().bound_type_of(def_id).subst(self.tcx(), substs)])
}
}
}
@ -2068,12 +2066,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
impl_def_id: DefId,
obligation: &TraitObligation<'tcx>,
) -> Result<Normalized<'tcx, SubstsRef<'tcx>>, ()> {
let impl_trait_ref = self.tcx().impl_trait_ref(impl_def_id).unwrap();
let impl_trait_ref = self.tcx().bound_impl_trait_ref(impl_def_id).unwrap();
// Before we create the substitutions and everything, first
// consider a "quick reject". This avoids creating more types
// and so forth that we need to.
if self.fast_reject_trait_refs(obligation, &impl_trait_ref) {
if self.fast_reject_trait_refs(obligation, &impl_trait_ref.0) {
return Err(());
}
@ -2332,7 +2330,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
param_env,
cause.clone(),
recursion_depth,
predicate.subst(tcx, substs),
EarlyBinder(*predicate).subst(tcx, substs),
&mut obligations,
);
obligations.push(Obligation { cause, recursion_depth, param_env, predicate });