bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Revert "Auto merge of #79637 - spastorino:revert-trait-inheritance-self, r=Mark-Simulacrum"

Browse source 
This reverts commit b4def89d76, reversing
changes made to 7dc1e852d4.
This commit is contained in:
Santiago Pastorino 2020-12-03 20:10:55 -03:00
parent 23adf9fd84
commit 7aa602b84c
No known key found for this signature in database
GPG key ID: 8131A24E0C79EFAF
28 changed files with 500 additions and 152 deletions
Download patch file Download diff file Expand all files Collapse all files

68
compiler/rustc_typeck/src/astconv/mod.rs
View file

@ -49,9 +49,10 @@ pub trait AstConv<'tcx> {
fn default_constness_for_trait_bounds(&self) -> Constness;
/// Returns predicates in scope of the form `X: Foo`, where `X` is
/// a type parameter `X` with the given id `def_id`. This is a
/// subset of the full set of predicates.
/// Returns predicates in scope of the form `X: Foo<T>`, where `X`
/// is a type parameter `X` with the given id `def_id` and T
/// matches `assoc_name`. This is a subset of the full set of
/// predicates.
///
/// This is used for one specific purpose: resolving "short-hand"
/// associated type references like `T::Item`. In principle, we
@ -60,7 +61,12 @@ pub trait AstConv<'tcx> {
/// but this can lead to cycle errors. The problem is that we have
/// to do this resolution *in order to create the predicates in
/// the first place*. Hence, we have this "special pass".
fn get_type_parameter_bounds(&self, span: Span, def_id: DefId) -> ty::GenericPredicates<'tcx>;
fn get_type_parameter_bounds(
&self,
span: Span,
def_id: DefId,
assoc_name: Ident,
) -> ty::GenericPredicates<'tcx>;
/// Returns the lifetime to use when a lifetime is omitted (and not elided).
fn re_infer(&self, param: Option<&ty::GenericParamDef>, span: Span)
@ -792,7 +798,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
}
// Returns `true` if a bounds list includes `?Sized`.
pub fn is_unsized(&self, ast_bounds: &[hir::GenericBound<'_>], span: Span) -> bool {
pub fn is_unsized(&self, ast_bounds: &[&hir::GenericBound<'_>], span: Span) -> bool {
let tcx = self.tcx();
// Try to find an unbound in bounds.
@ -850,7 +856,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
fn add_bounds(
&self,
param_ty: Ty<'tcx>,
ast_bounds: &[hir::GenericBound<'_>],
ast_bounds: &[&hir::GenericBound<'_>],
bounds: &mut Bounds<'tcx>,
) {
let constness = self.default_constness_for_trait_bounds();
@ -865,7 +871,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
hir::GenericBound::Trait(_, hir::TraitBoundModifier::Maybe) => {}
hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => self
.instantiate_lang_item_trait_ref(
lang_item, span, hir_id, args, param_ty, bounds,
*lang_item, *span, *hir_id, args, param_ty, bounds,
),
hir::GenericBound::Outlives(ref l) => bounds
.region_bounds
@ -896,6 +902,42 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
ast_bounds: &[hir::GenericBound<'_>],
sized_by_default: SizedByDefault,
span: Span,
) -> Bounds<'tcx> {
let ast_bounds: Vec<_> = ast_bounds.iter().collect();
self.compute_bounds_inner(param_ty, &ast_bounds, sized_by_default, span)
}
/// Convert the bounds in `ast_bounds` that refer to traits which define an associated type
/// named `assoc_name` into ty::Bounds. Ignore the rest.
pub fn compute_bounds_that_match_assoc_type(
&self,
param_ty: Ty<'tcx>,
ast_bounds: &[hir::GenericBound<'_>],
sized_by_default: SizedByDefault,
span: Span,
assoc_name: Ident,
) -> Bounds<'tcx> {
let mut result = Vec::new();
for ast_bound in ast_bounds {
if let Some(trait_ref) = ast_bound.trait_ref() {
if let Some(trait_did) = trait_ref.trait_def_id() {
if self.tcx().trait_may_define_assoc_type(trait_did, assoc_name) {
result.push(ast_bound);
}
}
}
}
self.compute_bounds_inner(param_ty, &result, sized_by_default, span)
}
fn compute_bounds_inner(
&self,
param_ty: Ty<'tcx>,
ast_bounds: &[&hir::GenericBound<'_>],
sized_by_default: SizedByDefault,
span: Span,
) -> Bounds<'tcx> {
let mut bounds = Bounds::default();
@ -1098,7 +1140,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
// parameter to have a skipped binder.
let param_ty =
tcx.mk_projection(assoc_ty.def_id, projection_ty.skip_binder().substs);
self.add_bounds(param_ty, ast_bounds, bounds);
let ast_bounds: Vec<_> = ast_bounds.iter().collect();
self.add_bounds(param_ty, &ast_bounds, bounds);
}
}
Ok(())
@ -1413,8 +1456,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
ty_param_def_id, assoc_name, span,
);
let predicates =
&self.get_type_parameter_bounds(span, ty_param_def_id.to_def_id()).predicates;
let predicates = &self
.get_type_parameter_bounds(span, ty_param_def_id.to_def_id(), assoc_name)
.predicates;
debug!("find_bound_for_assoc_item: predicates={:#?}", predicates);
@ -1422,12 +1466,14 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
let param_name = tcx.hir().ty_param_name(param_hir_id);
self.one_bound_for_assoc_type(
|| {
traits::transitive_bounds(
traits::transitive_bounds_that_define_assoc_type(
tcx,
predicates.iter().filter_map(|(p, _)| {
p.to_opt_poly_trait_ref().map(|trait_ref| trait_ref.value)
}),
assoc_name,
)
.into_iter()
},
|| param_name.to_string(),
assoc_name,

8
compiler/rustc_typeck/src/check/fn_ctxt/mod.rs
View file

@ -20,6 +20,7 @@ use rustc_middle::ty::fold::TypeFoldable;
use rustc_middle::ty::subst::GenericArgKind;
use rustc_middle::ty::{self, Const, Ty, TyCtxt};
use rustc_session::Session;
use rustc_span::symbol::Ident;
use rustc_span::{self, Span};
use rustc_trait_selection::traits::{ObligationCause, ObligationCauseCode};
@ -183,7 +184,12 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
}
}
fn get_type_parameter_bounds(&self, _: Span, def_id: DefId) -> ty::GenericPredicates<'tcx> {
fn get_type_parameter_bounds(
&self,
_: Span,
def_id: DefId,
_: Ident,
) -> ty::GenericPredicates<'tcx> {
let tcx = self.tcx;
let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
let item_id = tcx.hir().ty_param_owner(hir_id);

187
compiler/rustc_typeck/src/collect.rs
View file

@ -1,3 +1,4 @@
// ignore-tidy-filelength
//! "Collection" is the process of determining the type and other external
//! details of each item in Rust. Collection is specifically concerned
//! with *inter-procedural* things -- for example, for a function
@ -77,6 +78,7 @@ pub fn provide(providers: &mut Providers) {
projection_ty_from_predicates,
explicit_predicates_of,
super_predicates_of,
super_predicates_that_define_assoc_type,
trait_explicit_predicates_and_bounds,
type_param_predicates,
trait_def,
@ -308,8 +310,17 @@ impl AstConv<'tcx> for ItemCtxt<'tcx> {
}
}
fn get_type_parameter_bounds(&self, span: Span, def_id: DefId) -> ty::GenericPredicates<'tcx> {
self.tcx.at(span).type_param_predicates((self.item_def_id, def_id.expect_local()))
fn get_type_parameter_bounds(
&self,
span: Span,
def_id: DefId,
assoc_name: Ident,
) -> ty::GenericPredicates<'tcx> {
self.tcx.at(span).type_param_predicates((
self.item_def_id,
def_id.expect_local(),
assoc_name,
))
}
fn re_infer(&self, _: Option<&ty::GenericParamDef>, _: Span) -> Option<ty::Region<'tcx>> {
@ -490,7 +501,7 @@ fn get_new_lifetime_name<'tcx>(
/// `X: Foo` where `X` is the type parameter `def_id`.
fn type_param_predicates(
tcx: TyCtxt<'_>,
(item_def_id, def_id): (DefId, LocalDefId),
(item_def_id, def_id, assoc_name): (DefId, LocalDefId, Ident),
) -> ty::GenericPredicates<'_> {
use rustc_hir::*;
@ -515,7 +526,7 @@ fn type_param_predicates(
let mut result = parent
.map(|parent| {
let icx = ItemCtxt::new(tcx, parent);
icx.get_type_parameter_bounds(DUMMY_SP, def_id.to_def_id())
icx.get_type_parameter_bounds(DUMMY_SP, def_id.to_def_id(), assoc_name)
})
.unwrap_or_default();
let mut extend = None;
@ -558,12 +569,18 @@ fn type_param_predicates(
let icx = ItemCtxt::new(tcx, item_def_id);
let extra_predicates = extend.into_iter().chain(
icx.type_parameter_bounds_in_generics(ast_generics, param_id, ty, OnlySelfBounds(true))
.into_iter()
.filter(|(predicate, _)| match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(data, _) => data.self_ty().is_param(index),
_ => false,
}),
icx.type_parameter_bounds_in_generics(
ast_generics,
param_id,
ty,
OnlySelfBounds(true),
Some(assoc_name),
)
.into_iter()
.filter(|(predicate, _)| match predicate.kind().skip_binder() {
ty::PredicateAtom::Trait(data, _) => data.self_ty().is_param(index),
_ => false,
}),
);
result.predicates =
tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(extra_predicates));
@ -581,6 +598,7 @@ impl ItemCtxt<'tcx> {
param_id: hir::HirId,
ty: Ty<'tcx>,
only_self_bounds: OnlySelfBounds,
assoc_name: Option<Ident>,
) -> Vec<(ty::Predicate<'tcx>, Span)> {
let constness = self.default_constness_for_trait_bounds();
let from_ty_params = ast_generics
@ -591,6 +609,10 @@ impl ItemCtxt<'tcx> {
_ => None,
})
.flat_map(|bounds| bounds.iter())
.filter(|b| match assoc_name {
Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
None => true,
})
.flat_map(|b| predicates_from_bound(self, ty, b, constness));
let from_where_clauses = ast_generics
@ -609,12 +631,34 @@ impl ItemCtxt<'tcx> {
} else {
None
};
bp.bounds.iter().filter_map(move |b| bt.map(|bt| (bt, b)))
bp.bounds
.iter()
.filter(|b| match assoc_name {
Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
None => true,
})
.filter_map(move |b| bt.map(|bt| (bt, b)))
})
.flat_map(|(bt, b)| predicates_from_bound(self, bt, b, constness));
from_ty_params.chain(from_where_clauses).collect()
}
fn bound_defines_assoc_item(&self, b: &hir::GenericBound<'_>, assoc_name: Ident) -> bool {
debug!("bound_defines_assoc_item(b={:?}, assoc_name={:?})", b, assoc_name);
match b {
hir::GenericBound::Trait(poly_trait_ref, _) => {
let trait_ref = &poly_trait_ref.trait_ref;
if let Some(trait_did) = trait_ref.trait_def_id() {
self.tcx.trait_may_define_assoc_type(trait_did, assoc_name)
} else {
false
}
}
_ => false,
}
}
}
/// Tests whether this is the AST for a reference to the type
@ -983,54 +1027,91 @@ fn adt_def(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::AdtDef {
/// the transitive super-predicates are converted.
fn super_predicates_of(tcx: TyCtxt<'_>, trait_def_id: DefId) -> ty::GenericPredicates<'_> {
debug!("super_predicates(trait_def_id={:?})", trait_def_id);
let trait_hir_id = tcx.hir().local_def_id_to_hir_id(trait_def_id.expect_local());
tcx.super_predicates_that_define_assoc_type((trait_def_id, None))
}
let item = match tcx.hir().get(trait_hir_id) {
Node::Item(item) => item,
_ => bug!("trait_node_id {} is not an item", trait_hir_id),
};
let (generics, bounds) = match item.kind {
hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits),
hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits),
_ => span_bug!(item.span, "super_predicates invoked on non-trait"),
};
let icx = ItemCtxt::new(tcx, trait_def_id);
// Convert the bounds that follow the colon, e.g., `Bar + Zed` in `trait Foo: Bar + Zed`.
let self_param_ty = tcx.types.self_param;
let superbounds1 =
AstConv::compute_bounds(&icx, self_param_ty, bounds, SizedByDefault::No, item.span);
let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
// Convert any explicit superbounds in the where-clause,
// e.g., `trait Foo where Self: Bar`.
// In the case of trait aliases, however, we include all bounds in the where-clause,
// so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>`
// as one of its "superpredicates".
let is_trait_alias = tcx.is_trait_alias(trait_def_id);
let superbounds2 = icx.type_parameter_bounds_in_generics(
generics,
item.hir_id,
self_param_ty,
OnlySelfBounds(!is_trait_alias),
/// Ensures that the super-predicates of the trait with a `DefId`
/// of `trait_def_id` are converted and stored. This also ensures that
/// the transitive super-predicates are converted.
fn super_predicates_that_define_assoc_type(
tcx: TyCtxt<'_>,
(trait_def_id, assoc_name): (DefId, Option<Ident>),
) -> ty::GenericPredicates<'_> {
debug!(
"super_predicates_that_define_assoc_type(trait_def_id={:?}, assoc_name={:?})",
trait_def_id, assoc_name
);
if trait_def_id.is_local() {
debug!("super_predicates_that_define_assoc_type: local trait_def_id={:?}", trait_def_id);
let trait_hir_id = tcx.hir().local_def_id_to_hir_id(trait_def_id.expect_local());
// Combine the two lists to form the complete set of superbounds:
let superbounds = &*tcx.arena.alloc_from_iter(superbounds1.into_iter().chain(superbounds2));
let item = match tcx.hir().get(trait_hir_id) {
Node::Item(item) => item,
_ => bug!("trait_node_id {} is not an item", trait_hir_id),
};
// Now require that immediate supertraits are converted,
// which will, in turn, reach indirect supertraits.
for &(pred, span) in superbounds {
debug!("superbound: {:?}", pred);
if let ty::PredicateKind::Trait(bound, _) = pred.kind().skip_binder() {
tcx.at(span).super_predicates_of(bound.def_id());
let (generics, bounds) = match item.kind {
hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits),
hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits),
_ => span_bug!(item.span, "super_predicates invoked on non-trait"),
};
let icx = ItemCtxt::new(tcx, trait_def_id);
// Convert the bounds that follow the colon, e.g., `Bar + Zed` in `trait Foo: Bar + Zed`.
let self_param_ty = tcx.types.self_param;
let superbounds1 = if let Some(assoc_name) = assoc_name {
AstConv::compute_bounds_that_match_assoc_type(
&icx,
self_param_ty,
&bounds,
SizedByDefault::No,
item.span,
assoc_name,
)
} else {
AstConv::compute_bounds(&icx, self_param_ty, &bounds, SizedByDefault::No, item.span)
};
let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
// Convert any explicit superbounds in the where-clause,
// e.g., `trait Foo where Self: Bar`.
// In the case of trait aliases, however, we include all bounds in the where-clause,
// so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>`
// as one of its "superpredicates".
let is_trait_alias = tcx.is_trait_alias(trait_def_id);
let superbounds2 = icx.type_parameter_bounds_in_generics(
generics,
item.hir_id,
self_param_ty,
OnlySelfBounds(!is_trait_alias),
assoc_name,
);
// Combine the two lists to form the complete set of superbounds:
let superbounds = &*tcx.arena.alloc_from_iter(superbounds1.into_iter().chain(superbounds2));
// Now require that immediate supertraits are converted,
// which will, in turn, reach indirect supertraits.
if assoc_name.is_none() {
// Now require that immediate supertraits are converted,
// which will, in turn, reach indirect supertraits.
for &(pred, span) in superbounds {
debug!("superbound: {:?}", pred);
if let ty::PredicateKind::Trait(bound, _) = pred.kind().skip_binder() {
tcx.at(span).super_predicates_of(bound.def_id());
}
}
}
}
ty::GenericPredicates { parent: None, predicates: superbounds }
ty::GenericPredicates { parent: None, predicates: superbounds }
} else {
// if `assoc_name` is None, then the query should've been redirected to an
// external provider
assert!(assoc_name.is_some());
tcx.super_predicates_of(trait_def_id)
}
}
fn trait_def(tcx: TyCtxt<'_>, def_id: DefId) -> ty::TraitDef {

4
compiler/rustc_typeck/src/collect/item_bounds.rs
View file

@ -28,7 +28,7 @@ fn associated_type_bounds<'tcx>(
let bounds = AstConv::compute_bounds(
&ItemCtxt::new(tcx, assoc_item_def_id),
item_ty,
bounds,
&bounds,
SizedByDefault::Yes,
span,
);
@ -69,7 +69,7 @@ fn opaque_type_bounds<'tcx>(
let bounds = AstConv::compute_bounds(
&ItemCtxt::new(tcx, opaque_def_id),
item_ty,
bounds,
&bounds,
SizedByDefault::Yes,
span,
)