69 lines
2.2 KiB
Rust
69 lines
2.2 KiB
Rust
//! Bounds are restrictions applied to some types after they've been converted into the
|
|
//! `ty` form from the HIR.
|
|
|
|
use rustc_hir::LangItem;
|
|
use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt};
|
|
use rustc_span::Span;
|
|
|
|
/// Collects together a list of type bounds. These lists of bounds occur in many places
|
|
/// in Rust's syntax:
|
|
///
|
|
/// ```text
|
|
/// trait Foo: Bar + Baz { }
|
|
/// ^^^^^^^^^ supertrait list bounding the `Self` type parameter
|
|
///
|
|
/// fn foo<T: Bar + Baz>() { }
|
|
/// ^^^^^^^^^ bounding the type parameter `T`
|
|
///
|
|
/// impl dyn Bar + Baz
|
|
/// ^^^^^^^^^ bounding the type-erased dynamic type
|
|
/// ```
|
|
///
|
|
/// Our representation is a bit mixed here -- in some cases, we
|
|
/// include the self type (e.g., `trait_bounds`) but in others we do not
|
|
#[derive(Default, PartialEq, Eq, Clone, Debug)]
|
|
pub struct Bounds<'tcx> {
|
|
pub predicates: Vec<(ty::Predicate<'tcx>, Span)>,
|
|
}
|
|
|
|
impl<'tcx> Bounds<'tcx> {
|
|
pub fn push_region_bound(
|
|
&mut self,
|
|
tcx: TyCtxt<'tcx>,
|
|
region: ty::PolyTypeOutlivesPredicate<'tcx>,
|
|
span: Span,
|
|
) {
|
|
self.predicates.push((region.to_predicate(tcx), span));
|
|
}
|
|
|
|
pub fn push_trait_bound(
|
|
&mut self,
|
|
tcx: TyCtxt<'tcx>,
|
|
trait_ref: ty::PolyTraitRef<'tcx>,
|
|
span: Span,
|
|
constness: ty::BoundConstness,
|
|
) {
|
|
self.predicates.push((trait_ref.with_constness(constness).to_predicate(tcx), span));
|
|
}
|
|
|
|
pub fn push_projection_bound(
|
|
&mut self,
|
|
tcx: TyCtxt<'tcx>,
|
|
projection: ty::PolyProjectionPredicate<'tcx>,
|
|
span: Span,
|
|
) {
|
|
self.predicates.push((projection.to_predicate(tcx), span));
|
|
}
|
|
|
|
pub fn push_sized(&mut self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, span: Span) {
|
|
let sized_def_id = tcx.require_lang_item(LangItem::Sized, Some(span));
|
|
let trait_ref = ty::Binder::dummy(tcx.mk_trait_ref(sized_def_id, [ty]));
|
|
// Preferrable to put this obligation first, since we report better errors for sized ambiguity.
|
|
self.predicates.insert(0, (trait_ref.without_const().to_predicate(tcx), span));
|
|
}
|
|
|
|
pub fn predicates(&self) -> impl Iterator<Item = (ty::Predicate<'tcx>, Span)> + '_ {
|
|
self.predicates.iter().cloned()
|
|
}
|
|
}
|