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[3/n] rustc: unify and simplify managing associated items. #37402

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Nov 10, 2016
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12 changes: 6 additions & 6 deletions src/librustc/dep_graph/dep_node.rs
Original file line number Diff line number Diff line change
Expand Up @@ -103,11 +103,11 @@ pub enum DepNode<D: Clone + Debug> {
// nodes. Often we map multiple tables to the same node if there
// is no point in distinguishing them (e.g., both the type and
// predicates for an item wind up in `ItemSignature`).
ImplOrTraitItems(D),
AssociatedItems(D),
ItemSignature(D),
FieldTy(D),
SizedConstraint(D),
ImplOrTraitItemDefIds(D),
AssociatedItemDefIds(D),
InherentImpls(D),

// The set of impls for a given trait. Ultimately, it would be
Expand Down Expand Up @@ -153,10 +153,10 @@ impl<D: Clone + Debug> DepNode<D> {
TransCrateItem,
TypeckItemType,
TypeckItemBody,
ImplOrTraitItems,
AssociatedItems,
ItemSignature,
FieldTy,
ImplOrTraitItemDefIds,
AssociatedItemDefIds,
InherentImpls,
TraitImpls,
ReprHints,
Expand Down Expand Up @@ -219,11 +219,11 @@ impl<D: Clone + Debug> DepNode<D> {
RvalueCheck(ref d) => op(d).map(RvalueCheck),
TransCrateItem(ref d) => op(d).map(TransCrateItem),
TransInlinedItem(ref d) => op(d).map(TransInlinedItem),
ImplOrTraitItems(ref d) => op(d).map(ImplOrTraitItems),
AssociatedItems(ref d) => op(d).map(AssociatedItems),
ItemSignature(ref d) => op(d).map(ItemSignature),
FieldTy(ref d) => op(d).map(FieldTy),
SizedConstraint(ref d) => op(d).map(SizedConstraint),
ImplOrTraitItemDefIds(ref d) => op(d).map(ImplOrTraitItemDefIds),
AssociatedItemDefIds(ref d) => op(d).map(AssociatedItemDefIds),
InherentImpls(ref d) => op(d).map(InherentImpls),
TraitImpls(ref d) => op(d).map(TraitImpls),
TraitItems(ref d) => op(d).map(TraitItems),
Expand Down
14 changes: 7 additions & 7 deletions src/librustc/middle/cstore.rs
Original file line number Diff line number Diff line change
Expand Up @@ -147,7 +147,7 @@ pub trait CrateStore<'tcx> {
fn implementations_of_trait(&self, filter: Option<DefId>) -> Vec<DefId>;

// impl info
fn impl_or_trait_items(&self, def_id: DefId) -> Vec<DefId>;
fn associated_item_def_ids(&self, def_id: DefId) -> Vec<DefId>;
fn impl_trait_ref<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
-> Option<ty::TraitRef<'tcx>>;
fn impl_polarity(&self, def: DefId) -> hir::ImplPolarity;
Expand All @@ -157,8 +157,8 @@ pub trait CrateStore<'tcx> {

// trait/impl-item info
fn trait_of_item(&self, def_id: DefId) -> Option<DefId>;
fn impl_or_trait_item<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
-> Option<ty::ImplOrTraitItem<'tcx>>;
fn associated_item<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
-> Option<ty::AssociatedItem>;

// flags
fn is_const_fn(&self, did: DefId) -> bool;
Expand Down Expand Up @@ -311,8 +311,8 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
}

// impl info
fn impl_or_trait_items(&self, def_id: DefId) -> Vec<DefId>
{ bug!("impl_or_trait_items") }
fn associated_item_def_ids(&self, def_id: DefId) -> Vec<DefId>
{ bug!("associated_items") }
fn impl_trait_ref<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
-> Option<ty::TraitRef<'tcx>> { bug!("impl_trait_ref") }
fn impl_polarity(&self, def: DefId) -> hir::ImplPolarity { bug!("impl_polarity") }
Expand All @@ -323,8 +323,8 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {

// trait/impl-item info
fn trait_of_item(&self, def_id: DefId) -> Option<DefId> { bug!("trait_of_item") }
fn impl_or_trait_item<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
-> Option<ty::ImplOrTraitItem<'tcx>> { bug!("impl_or_trait_item") }
fn associated_item<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
-> Option<ty::AssociatedItem> { bug!("associated_item") }

// flags
fn is_const_fn(&self, did: DefId) -> bool { bug!("is_const_fn") }
Expand Down
5 changes: 2 additions & 3 deletions src/librustc/middle/dead.rs
Original file line number Diff line number Diff line change
Expand Up @@ -471,11 +471,10 @@ impl<'a, 'tcx> DeadVisitor<'a, 'tcx> {
// This is done to handle the case where, for example, the static
// method of a private type is used, but the type itself is never
// called directly.
let impl_items = self.tcx.impl_or_trait_item_def_ids.borrow();
if let Some(impl_list) =
self.tcx.inherent_impls.borrow().get(&self.tcx.map.local_def_id(id)) {
for impl_did in impl_list.iter() {
for &item_did in &impl_items[impl_did][..] {
for &impl_did in impl_list.iter() {
for &item_did in &self.tcx.associated_item_def_ids(impl_did)[..] {
if let Some(item_node_id) = self.tcx.map.as_local_node_id(item_did) {
if self.live_symbols.contains(&item_node_id) {
return true;
Expand Down
4 changes: 2 additions & 2 deletions src/librustc/middle/expr_use_visitor.rs
Original file line number Diff line number Diff line change
Expand Up @@ -227,8 +227,8 @@ impl OverloadedCallType {
}

fn from_method_id(tcx: TyCtxt, method_id: DefId) -> OverloadedCallType {
let method = tcx.impl_or_trait_item(method_id);
OverloadedCallType::from_trait_id(tcx, method.container().id())
let method = tcx.associated_item(method_id);
OverloadedCallType::from_trait_id(tcx, method.container.id())
}
}

Expand Down
20 changes: 5 additions & 15 deletions src/librustc/middle/stability.rs
Original file line number Diff line number Diff line change
Expand Up @@ -529,14 +529,11 @@ pub fn check_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
// items.
hir::ItemImpl(.., Some(ref t), _, ref impl_items) => {
let trait_did = tcx.expect_def(t.ref_id).def_id();
let trait_items = tcx.trait_items(trait_did);

for impl_item in impl_items {
let item = trait_items.iter().find(|item| {
item.name() == impl_item.name
}).unwrap();
let item = tcx.associated_items(trait_did)
.find(|item| item.name == impl_item.name).unwrap();
if warn_about_defns {
maybe_do_stability_check(tcx, item.def_id(), impl_item.span, cb);
maybe_do_stability_check(tcx, item.def_id, impl_item.span, cb);
}
}
}
Expand Down Expand Up @@ -685,15 +682,8 @@ fn is_internal<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, span: Span) -> bool {
}

fn is_staged_api<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: DefId) -> bool {
match tcx.trait_item_of_item(id) {
Some(trait_method_id) if trait_method_id != id => {
is_staged_api(tcx, trait_method_id)
}
_ => {
*tcx.stability.borrow_mut().staged_api.entry(id.krate).or_insert_with(
|| tcx.sess.cstore.is_staged_api(id.krate))
}
}
*tcx.stability.borrow_mut().staged_api.entry(id.krate).or_insert_with(
|| tcx.sess.cstore.is_staged_api(id.krate))
}

impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
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why does this case not matter anymore?

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@eddyb eddyb Nov 1, 2016

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Took me a bit to remember, but it never should've really mattered. Regardless of past practices, we now never refer to associated items in impls of traits, only to the definition in the trait, outside of monomorphization.

Expand Down
14 changes: 6 additions & 8 deletions src/librustc/traits/error_reporting.rs
Original file line number Diff line number Diff line change
Expand Up @@ -663,25 +663,23 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
in the supertrait listing"
}

ObjectSafetyViolation::Method(method,
ObjectSafetyViolation::Method(name,
MethodViolationCode::StaticMethod) => {
buf = format!("method `{}` has no receiver",
method.name);
buf = format!("method `{}` has no receiver", name);
&buf
}

ObjectSafetyViolation::Method(method,
ObjectSafetyViolation::Method(name,
MethodViolationCode::ReferencesSelf) => {
buf = format!("method `{}` references the `Self` type \
in its arguments or return type",
method.name);
name);
&buf
}

ObjectSafetyViolation::Method(method,
ObjectSafetyViolation::Method(name,
MethodViolationCode::Generic) => {
buf = format!("method `{}` has generic type parameters",
method.name);
buf = format!("method `{}` has generic type parameters", name);
&buf
}
};
Expand Down
20 changes: 8 additions & 12 deletions src/librustc/traits/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -578,18 +578,14 @@ pub fn get_vtable_methods<'a, 'tcx>(
supertraits(tcx, trait_ref).flat_map(move |trait_ref| {
tcx.populate_implementations_for_trait_if_necessary(trait_ref.def_id());

let trait_item_def_ids = tcx.impl_or_trait_items(trait_ref.def_id());
let trait_methods = (0..trait_item_def_ids.len()).filter_map(move |i| {
match tcx.impl_or_trait_item(trait_item_def_ids[i]) {
ty::MethodTraitItem(m) => Some(m),
_ => None
}
});
let trait_methods = tcx.associated_items(trait_ref.def_id())
.filter(|item| item.kind == ty::AssociatedKind::Method);

// Now list each method's DefId and Substs (for within its trait).
// If the method can never be called from this object, produce None.
trait_methods.map(move |trait_method| {
debug!("get_vtable_methods: trait_method={:?}", trait_method);
let def_id = trait_method.def_id;

// Some methods cannot be called on an object; skip those.
if !tcx.is_vtable_safe_method(trait_ref.def_id(), &trait_method) {
Expand All @@ -599,21 +595,21 @@ pub fn get_vtable_methods<'a, 'tcx>(

// the method may have some early-bound lifetimes, add
// regions for those
let substs = Substs::for_item(tcx, trait_method.def_id,
|_, _| tcx.mk_region(ty::ReErased),
|def, _| trait_ref.substs().type_for_def(def));
let substs = Substs::for_item(tcx, def_id,
|_, _| tcx.mk_region(ty::ReErased),
|def, _| trait_ref.substs().type_for_def(def));

// It's possible that the method relies on where clauses that
// do not hold for this particular set of type parameters.
// Note that this method could then never be called, so we
// do not want to try and trans it, in that case (see #23435).
let predicates = trait_method.predicates.instantiate_own(tcx, substs);
let predicates = tcx.lookup_predicates(def_id).instantiate_own(tcx, substs);
if !normalize_and_test_predicates(tcx, predicates.predicates) {
debug!("get_vtable_methods: predicates do not hold");
return None;
}

Some((trait_method.def_id, substs))
Some((def_id, substs))
})
})
}
Expand Down
48 changes: 17 additions & 31 deletions src/librustc/traits/object_safety.rs
Original file line number Diff line number Diff line change
Expand Up @@ -22,11 +22,10 @@ use super::elaborate_predicates;
use hir::def_id::DefId;
use traits;
use ty::{self, ToPolyTraitRef, Ty, TyCtxt, TypeFoldable};
use std::rc::Rc;
use syntax::ast;

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum ObjectSafetyViolation<'tcx> {
pub enum ObjectSafetyViolation {
/// Self : Sized declared on the trait
SizedSelf,

Expand All @@ -35,7 +34,7 @@ pub enum ObjectSafetyViolation<'tcx> {
SupertraitSelf,

/// Method has something illegal
Method(Rc<ty::Method<'tcx>>, MethodViolationCode),
Method(ast::Name, MethodViolationCode),
}

/// Reasons a method might not be object-safe.
Expand Down Expand Up @@ -77,7 +76,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
/// because `object_safety_violations` can't be used during
/// type collection.
pub fn astconv_object_safety_violations(self, trait_def_id: DefId)
-> Vec<ObjectSafetyViolation<'tcx>>
-> Vec<ObjectSafetyViolation>
{
let mut violations = vec![];

Expand All @@ -93,29 +92,23 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
}

pub fn object_safety_violations(self, trait_def_id: DefId)
-> Vec<ObjectSafetyViolation<'tcx>>
-> Vec<ObjectSafetyViolation>
{
traits::supertrait_def_ids(self, trait_def_id)
.flat_map(|def_id| self.object_safety_violations_for_trait(def_id))
.collect()
}

fn object_safety_violations_for_trait(self, trait_def_id: DefId)
-> Vec<ObjectSafetyViolation<'tcx>>
-> Vec<ObjectSafetyViolation>
{
// Check methods for violations.
let mut violations: Vec<_> =
self.trait_items(trait_def_id).iter()
let mut violations: Vec<_> = self.associated_items(trait_def_id)
.filter(|item| item.kind == ty::AssociatedKind::Method)
.filter_map(|item| {
match *item {
ty::MethodTraitItem(ref m) => {
self.object_safety_violation_for_method(trait_def_id, &m)
.map(|code| ObjectSafetyViolation::Method(m.clone(), code))
}
_ => None,
}
})
.collect();
self.object_safety_violation_for_method(trait_def_id, &item)
.map(|code| ObjectSafetyViolation::Method(item.name, code))
}).collect();

// Check the trait itself.
if self.trait_has_sized_self(trait_def_id) {
Expand Down Expand Up @@ -198,7 +191,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
/// Returns `Some(_)` if this method makes the containing trait not object safe.
fn object_safety_violation_for_method(self,
trait_def_id: DefId,
method: &ty::Method<'gcx>)
method: &ty::AssociatedItem)
-> Option<MethodViolationCode>
{
// Any method that has a `Self : Sized` requisite is otherwise
Expand All @@ -216,7 +209,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
/// otherwise ensure that they cannot be used when `Self=Trait`.
pub fn is_vtable_safe_method(self,
trait_def_id: DefId,
method: &ty::Method<'gcx>)
method: &ty::AssociatedItem)
-> bool
{
// Any method that has a `Self : Sized` requisite can't be called.
Expand All @@ -233,26 +226,19 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
/// `Self:Sized`.
fn virtual_call_violation_for_method(self,
trait_def_id: DefId,
method: &ty::Method<'tcx>)
method: &ty::AssociatedItem)
-> Option<MethodViolationCode>
{
// The method's first parameter must be something that derefs (or
// autorefs) to `&self`. For now, we only accept `self`, `&self`
// and `Box<Self>`.
match method.explicit_self {
ty::ExplicitSelfCategory::Static => {
return Some(MethodViolationCode::StaticMethod);
}

ty::ExplicitSelfCategory::ByValue |
ty::ExplicitSelfCategory::ByReference(..) |
ty::ExplicitSelfCategory::ByBox => {
}
if !method.method_has_self_argument {
return Some(MethodViolationCode::StaticMethod);
}

// The `Self` type is erased, so it should not appear in list of
// arguments or return type apart from the receiver.
let ref sig = method.fty.sig;
let ref sig = self.lookup_item_type(method.def_id).ty.fn_sig();
for &input_ty in &sig.0.inputs[1..] {
if self.contains_illegal_self_type_reference(trait_def_id, input_ty) {
return Some(MethodViolationCode::ReferencesSelf);
Expand All @@ -263,7 +249,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
}

// We can't monomorphize things like `fn foo<A>(...)`.
if !method.generics.types.is_empty() {
if !self.lookup_generics(method.def_id).types.is_empty() {
return Some(MethodViolationCode::Generic);
}

Expand Down
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