bjoernager/rust
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Add trait_object_dummy_self to CommonTypes

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This commit is contained in:
flip1995 2019-04-03 11:46:40 +02:00
parent dd7483c750
commit 51a792d01b
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GPG key ID: 693086869D506637
2 changed files with 15 additions and 12 deletions
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7
src/librustc/ty/context.rs
View file

@ -219,6 +219,11 @@ pub struct CommonTypes<'tcx> {
pub never: Ty<'tcx>,
pub err: Ty<'tcx>,
/// Dummy type used for the `Self` of a `TraitRef` created for converting
/// a trait object, and which gets removed in `ExistentialTraitRef`.
/// This type must not appear anywhere in other converted types.
pub trait_object_dummy_self: Ty<'tcx>,
pub re_empty: Region<'tcx>,
pub re_static: Region<'tcx>,
pub re_erased: Region<'tcx>,
@ -955,6 +960,8 @@ impl<'tcx> CommonTypes<'tcx> {
f32: mk(Float(ast::FloatTy::F32)),
f64: mk(Float(ast::FloatTy::F64)),
trait_object_dummy_self: mk(Infer(ty::FreshTy(0))),
re_empty: mk_region(RegionKind::ReEmpty),
re_static: mk_region(RegionKind::ReStatic),
re_erased: mk_region(RegionKind::ReErased),

20
src/librustc_typeck/astconv.rs
View file

@ -99,12 +99,6 @@ enum GenericArgPosition {
MethodCall,
}
/// Dummy type used for the `Self` of a `TraitRef` created for converting
/// a trait object, and which gets removed in `ExistentialTraitRef`.
/// This type must not appear anywhere in other converted types.
#[cfg_attr(not(stage0), allow(usage_of_ty_tykind))]
const TRAIT_OBJECT_DUMMY_SELF: ty::TyKind<'static> = ty::Infer(ty::FreshTy(0));
impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
pub fn ast_region_to_region(&self,
lifetime: &hir::Lifetime,
@ -596,7 +590,9 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
infer_types,
);
let is_object = self_ty.map_or(false, |ty| ty.sty == TRAIT_OBJECT_DUMMY_SELF);
let is_object = self_ty.map_or(false, |ty| {
ty.sty == self.tcx().types.trait_object_dummy_self.sty
});
let default_needs_object_self = |param: &ty::GenericParamDef| {
if let GenericParamDefKind::Type { has_default, .. } = param.kind {
if is_object && has_default {
@ -957,10 +953,10 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
}
/// Transform a `PolyTraitRef` into a `PolyExistentialTraitRef` by
/// removing the dummy `Self` type (`TRAIT_OBJECT_DUMMY_SELF`).
/// removing the dummy `Self` type (`trait_object_dummy_self`).
fn trait_ref_to_existential(&self, trait_ref: ty::TraitRef<'tcx>)
-> ty::ExistentialTraitRef<'tcx> {
if trait_ref.self_ty().sty != TRAIT_OBJECT_DUMMY_SELF {
if trait_ref.self_ty().sty != self.tcx().types.trait_object_dummy_self.sty {
bug!("trait_ref_to_existential called on {:?} with non-dummy Self", trait_ref);
}
ty::ExistentialTraitRef::erase_self_ty(self.tcx(), trait_ref)
@ -981,7 +977,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
}
let mut projection_bounds = Vec::new();
let dummy_self = tcx.mk_ty(TRAIT_OBJECT_DUMMY_SELF);
let dummy_self = self.tcx().types.trait_object_dummy_self;
let (principal, potential_assoc_types) = self.instantiate_poly_trait_ref(
&trait_bounds[0],
dummy_self,
@ -1031,7 +1027,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
}
ty::Predicate::Projection(pred) => {
// A `Self` within the original bound will be substituted with a
// `TRAIT_OBJECT_DUMMY_SELF`, so check for that.
// `trait_object_dummy_self`, so check for that.
let references_self =
pred.skip_binder().ty.walk().any(|t| t == dummy_self);
@ -1131,7 +1127,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
err.emit();
}
// Erase the `dummy_self` (`TRAIT_OBJECT_DUMMY_SELF`) used above.
// Erase the `dummy_self` (`trait_object_dummy_self`) used above.
let existential_principal = principal.map_bound(|trait_ref| {
self.trait_ref_to_existential(trait_ref)
});