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use rustc::traits::{
WellFormed,
DomainGoal,
GoalKind,
Clause,
Clauses,
ProgramClause,
ProgramClauseCategory,
};
use rustc::ty::{self, TyCtxt};
use rustc::hir;
use rustc::hir::def_id::DefId;
use rustc_target::spec::abi;
use crate::lowering::Lower;
use crate::generic_types;
use std::iter;
crate fn wf_clause_for_raw_ptr<'tcx>(
tcx: TyCtxt<'_, '_, 'tcx>,
mutbl: hir::Mutability
) -> Clauses<'tcx> {
let ptr_ty = generic_types::raw_ptr(tcx, mutbl);
let wf_clause = ProgramClause {
goal: DomainGoal::WellFormed(WellFormed::Ty(ptr_ty)),
hypotheses: ty::List::empty(),
category: ProgramClauseCategory::WellFormed,
};
let wf_clause = Clause::Implies(wf_clause);
// `forall<T> { WellFormed(*const T). }`
tcx.mk_clauses(iter::once(wf_clause))
}
crate fn wf_clause_for_fn_ptr<'tcx>(
tcx: TyCtxt<'_, '_, 'tcx>,
arity_and_output: usize,
variadic: bool,
unsafety: hir::Unsafety,
abi: abi::Abi
) -> Clauses<'tcx> {
let fn_ptr = generic_types::fn_ptr(tcx, arity_and_output, variadic, unsafety, abi);
let wf_clause = ProgramClause {
goal: DomainGoal::WellFormed(WellFormed::Ty(fn_ptr)),
hypotheses: ty::List::empty(),
category: ProgramClauseCategory::WellFormed,
};
let wf_clause = Clause::ForAll(ty::Binder::bind(wf_clause));
// `forall <T1, ..., Tn+1> { WellFormed(for<> fn(T1, ..., Tn) -> Tn+1). }`
// where `n + 1` == `arity_and_output`
tcx.mk_clauses(iter::once(wf_clause))
}
crate fn wf_clause_for_slice<'tcx>(tcx: TyCtxt<'_, '_, 'tcx>) -> Clauses<'tcx> {
let ty = generic_types::bound(tcx, 0);
let slice_ty = tcx.mk_slice(ty);
let sized_trait = match tcx.lang_items().sized_trait() {
Some(def_id) => def_id,
None => return ty::List::empty(),
};
let sized_implemented = ty::TraitRef {
def_id: sized_trait,
substs: tcx.mk_substs_trait(ty, ty::List::empty()),
};
let sized_implemented: DomainGoal<'_> = ty::TraitPredicate {
trait_ref: sized_implemented
}.lower();
let wf_clause = ProgramClause {
goal: DomainGoal::WellFormed(WellFormed::Ty(slice_ty)),
hypotheses: tcx.mk_goals(
iter::once(tcx.mk_goal(GoalKind::DomainGoal(sized_implemented)))
),
category: ProgramClauseCategory::WellFormed,
};
let wf_clause = Clause::ForAll(ty::Binder::bind(wf_clause));
// `forall<T> { WellFormed([T]) :- Implemented(T: Sized). }`
tcx.mk_clauses(iter::once(wf_clause))
}
crate fn wf_clause_for_array<'tcx>(
tcx: TyCtxt<'_, '_, 'tcx>,
length: &'tcx ty::Const<'tcx>
) -> Clauses<'tcx> {
let ty = generic_types::bound(tcx, 0);
let array_ty = tcx.mk_ty(ty::Array(ty, length));
let sized_trait = match tcx.lang_items().sized_trait() {
Some(def_id) => def_id,
None => return ty::List::empty(),
};
let sized_implemented = ty::TraitRef {
def_id: sized_trait,
substs: tcx.mk_substs_trait(ty, ty::List::empty()),
};
let sized_implemented: DomainGoal<'_> = ty::TraitPredicate {
trait_ref: sized_implemented
}.lower();
let wf_clause = ProgramClause {
goal: DomainGoal::WellFormed(WellFormed::Ty(array_ty)),
hypotheses: tcx.mk_goals(
iter::once(tcx.mk_goal(GoalKind::DomainGoal(sized_implemented)))
),
category: ProgramClauseCategory::WellFormed,
};
let wf_clause = Clause::ForAll(ty::Binder::bind(wf_clause));
// `forall<T> { WellFormed([T; length]) :- Implemented(T: Sized). }`
tcx.mk_clauses(iter::once(wf_clause))
}
crate fn wf_clause_for_tuple<'tcx>(
tcx: TyCtxt<'_, '_, 'tcx>,
arity: usize
) -> Clauses<'tcx> {
let type_list = generic_types::type_list(tcx, arity);
let tuple_ty = tcx.mk_ty(ty::Tuple(type_list));
let sized_trait = match tcx.lang_items().sized_trait() {
Some(def_id) => def_id,
None => return ty::List::empty(),
};
// If `arity == 0` (i.e. the unit type) or `arity == 1`, this list of
// hypotheses is actually empty.
let sized_implemented = type_list[0 .. std::cmp::max(arity, 1) - 1].iter()
.map(|ty| ty::TraitRef {
def_id: sized_trait,
substs: tcx.mk_substs_trait(ty.expect_ty(), ty::List::empty()),
})
.map(|trait_ref| ty::TraitPredicate { trait_ref })
.map(|predicate| predicate.lower());
let wf_clause = ProgramClause {
goal: DomainGoal::WellFormed(WellFormed::Ty(tuple_ty)),
hypotheses: tcx.mk_goals(
sized_implemented.map(|domain_goal| {
tcx.mk_goal(GoalKind::DomainGoal(domain_goal))
})
),
category: ProgramClauseCategory::WellFormed,
};
let wf_clause = Clause::ForAll(ty::Binder::bind(wf_clause));
// ```
// forall<T1, ..., Tn-1, Tn> {
// WellFormed((T1, ..., Tn)) :-
// Implemented(T1: Sized),
// ...
// Implemented(Tn-1: Sized).
// }
// ```
tcx.mk_clauses(iter::once(wf_clause))
}
crate fn wf_clause_for_ref<'tcx>(
tcx: TyCtxt<'_, '_, 'tcx>,
mutbl: hir::Mutability
) -> Clauses<'tcx> {
let region = tcx.mk_region(
ty::ReLateBound(ty::INNERMOST, ty::BoundRegion::BrAnon(0))
);
let ty = generic_types::bound(tcx, 1);
let ref_ty = tcx.mk_ref(region, ty::TypeAndMut {
ty,
mutbl,
});
let outlives: DomainGoal<'_> = ty::OutlivesPredicate(ty, region).lower();
let wf_clause = ProgramClause {
goal: DomainGoal::WellFormed(WellFormed::Ty(ref_ty)),
hypotheses: tcx.mk_goals(
iter::once(tcx.mk_goal(outlives.into_goal()))
),
category: ProgramClauseCategory::WellFormed,
};
let wf_clause = Clause::ForAll(ty::Binder::bind(wf_clause));
// `forall<'a, T> { WellFormed(&'a T) :- Outlives(T: 'a). }`
tcx.mk_clauses(iter::once(wf_clause))
}
crate fn wf_clause_for_fn_def<'tcx>(
tcx: TyCtxt<'_, '_, 'tcx>,
def_id: DefId
) -> Clauses<'tcx> {
let fn_def = generic_types::fn_def(tcx, def_id);
let wf_clause = ProgramClause {
goal: DomainGoal::WellFormed(WellFormed::Ty(fn_def)),
hypotheses: ty::List::empty(),
category: ProgramClauseCategory::WellFormed,
};
let wf_clause = Clause::ForAll(ty::Binder::bind(wf_clause));
// `forall <T1, ..., Tn+1> { WellFormed(fn some_fn(T1, ..., Tn) -> Tn+1). }`
// where `def_id` maps to the `some_fn` function definition
tcx.mk_clauses(iter::once(wf_clause))
}
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