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refactor

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This commit is contained in:
csmoe 2018-07-06 18:44:42 +08:00
parent ff83ef0c24
commit a6d4d2b945
1 changed files with 32 additions and 35 deletions
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67
src/librustc_traits/lowering.rs
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@ -13,9 +13,10 @@ use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
use rustc::hir::map::definitions::DefPathData;
use rustc::hir::{self, ImplPolarity};
use rustc::traits::{
Clause, Clauses, DomainGoal, Goal, PolyDomainGoal, ProgramClause, WhereClauseAtom,
Clause, Clauses, DomainGoal, FromEnv, Goal, PolyDomainGoal, ProgramClause, WellFormed,
WhereClause,
};
use rustc::ty::subst::Substs;
use rustc::ty::query::Providers;
use rustc::ty::{self, Slice, TyCtxt};
use rustc_data_structures::fx::FxHashSet;
use std::mem;
@ -139,11 +140,13 @@ impl<'tcx> IntoFromEnvGoal for DomainGoal<'tcx> {
impl<'tcx> IntoWellFormedGoal for DomainGoal<'tcx> {
fn into_wellformed_goal(self) -> DomainGoal<'tcx> {
use self::DomainGoal::*;
use self::WhereClause::*;
match self {
Holds(wc_atom) => WellFormed(wc_atom),
WellFormed(..) | FromEnv(..) | WellFormedTy(..) | FromEnvTy(..) | Normalize(..)
| RegionOutlives(..) | TypeOutlives(..) => self,
DomainGoal::Holds(Implemented(trait_ref)) => {
DomainGoal::WellFormed(WellFormed::Trait(trait_ref))
}
other => other,
}
}
}
@ -256,6 +259,8 @@ fn program_clauses_for_trait<'a, 'tcx>(
let clauses = iter::once(Clause::ForAll(ty::Binder::dummy(implemented_from_env)));
let where_clauses = &tcx.predicates_defined_on(def_id).predicates;
// Rule Implied-Bound-From-Trait
//
// For each where clause WC:
@ -266,7 +271,6 @@ fn program_clauses_for_trait<'a, 'tcx>(
// ```
// `FromEnv(WC) :- FromEnv(Self: Trait<P1..Pn>)`, for each where clause WC
let where_clauses = &tcx.predicates_defined_on(def_id).predicates;
let implied_bound_clauses = where_clauses
.into_iter()
.map(|wc| wc.lower())
@ -276,16 +280,8 @@ fn program_clauses_for_trait<'a, 'tcx>(
goal: goal.into_from_env_goal(),
hypotheses,
}))
.map(|wc| implied_bound_from_trait(tcx, trait_pred, wc));
let wellformed_clauses = wellformed_from_bound(tcx, trait_pred, &where_clauses[1..]);
tcx.mk_clauses(clauses.chain(implied_bound_clauses).chain(wellformed_clauses))
}
.map(Clause::ForAll);
fn wellformed_from_bound<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
trait_pred: ty::TraitPredicate<'tcx>,
where_clauses: &[ty::Predicate<'tcx>],
) -> iter::Once<Clause<'tcx>> {
// Rule WellFormed-TraitRef
//
// For each where clause WC:
@ -293,26 +289,27 @@ fn wellformed_from_bound<'a, 'tcx>(
// WellFormed(Self: Trait<P1..Pn>) :- Implemented(Self: Trait<P1..Pn>) && WellFormed(WC)
// }
// WellFormed(Self: Trait<P1..Pn>)
let wellformed_trait = DomainGoal::WellFormed(WhereClauseAtom::Implemented(trait_pred));
// Implemented(Self: Trait<P1..Pn>)
let impl_trait = ty::Binder::dummy(DomainGoal::Holds(WhereClauseAtom::Implemented(trait_pred)));
// WellFormed(WC)
let wellformed_wc = where_clause
.lower()
.map_bound(|wc| wc.into_wellformed_goal());
// Implemented(Self: Trait<P1..Pn>) && WellFormed(WC)
let mut wcs = vec![impl_trait];
wcs.extend(wellformed_wcs);
let wellformed_clauses = where_clauses
.into_iter()
.map(|wc| wc.lower())
// WellFormed(Self: Trait<P1..Pn>) :- Implemented(Self: Trait<P1..Pn>) && WellFormed(WC)
.map(|wc| {
wc.map_bound(|goal| ProgramClause {
goal: goal.into_wellformed_goal(),
hypotheses: tcx.mk_goals(
where_clauses
.into_iter()
.map(|wc| Goal::from_poly_domain_goal(wc.lower(), tcx)),
),
})
})
.map(Clause::ForAll);
let clause = ProgramClause {
goal: wellformed_trait,
hypotheses: tcx.mk_goals(
wcs.into_iter()
.map(|wc| Goal::from_poly_domain_goal(wc, tcx)),
),
};
iter::once(Clause::ForAll(ty::Binder::dummy(clause)))
tcx.mk_clauses(
clauses
.chain(implied_bound_clauses)
.chain(wellformed_clauses),
)
}
fn program_clauses_for_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Clauses<'tcx> {