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Auto merge of #26282 - arielb1:probe-leak, r=nikomatsakis

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It can introduce obligations to the fulfillment context, which would
incorrectly still remain after the probe finished.

Fixes #25679.

r? @eddyb
This commit is contained in:
bors 2015-06-15 21:27:43 +00:00
commit c656e99e43
4 changed files with 114 additions and 21 deletions
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4
src/librustc/middle/traits/project.rs
View file

@ -389,15 +389,19 @@ fn opt_normalize_projection_type<'a,'b,'tcx>(
}
}
Ok(ProjectedTy::NoProgress(projected_ty)) => {
debug!("normalize_projection_type: projected_ty={} no progress",
projected_ty.repr(selcx.tcx()));
Some(Normalized {
value: projected_ty,
obligations: vec!()
})
}
Err(ProjectionTyError::TooManyCandidates) => {
debug!("normalize_projection_type: too many candidates");
None
}
Err(ProjectionTyError::TraitSelectionError(_)) => {
debug!("normalize_projection_type: ERROR");
// if we got an error processing the `T as Trait` part,
// just return `ty::err` but add the obligation `T :
// Trait`, which when processed will cause the error to be

67
src/librustc_typeck/check/method/probe.rs
View file

@ -59,10 +59,12 @@ struct Candidate<'tcx> {
}
enum CandidateKind<'tcx> {
InherentImplCandidate(/* Impl */ ast::DefId, subst::Substs<'tcx>),
InherentImplCandidate(/* Impl */ ast::DefId, subst::Substs<'tcx>,
/* Normalize obligations */ Vec<traits::PredicateObligation<'tcx>>),
ObjectCandidate(/* Trait */ ast::DefId, /* method_num */ usize, /* vtable index */ usize),
ExtensionImplCandidate(/* Impl */ ast::DefId, ty::TraitRef<'tcx>,
subst::Substs<'tcx>, ItemIndex),
subst::Substs<'tcx>, ItemIndex,
/* Normalize obligations */ Vec<traits::PredicateObligation<'tcx>>),
ClosureCandidate(/* Trait */ ast::DefId, ItemIndex),
WhereClauseCandidate(ty::PolyTraitRef<'tcx>, ItemIndex),
ProjectionCandidate(ast::DefId, ItemIndex),
@ -398,16 +400,24 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
}
let (impl_ty, impl_substs) = self.impl_ty_and_substs(impl_def_id);
let impl_ty = self.fcx.instantiate_type_scheme(self.span, &impl_substs, &impl_ty);
let impl_ty = impl_ty.subst(self.tcx(), &impl_substs);
// Determine the receiver type that the method itself expects.
let xform_self_ty =
self.xform_self_ty(&item, impl_ty, &impl_substs);
let xform_self_ty = self.xform_self_ty(&item, impl_ty, &impl_substs);
// We can't use normalize_associated_types_in as it will pollute the
// fcx's fulfillment context after this probe is over.
let cause = traits::ObligationCause::misc(self.span, self.fcx.body_id);
let mut selcx = &mut traits::SelectionContext::new(self.fcx.infcx(), self.fcx);
let traits::Normalized { value: xform_self_ty, obligations } =
traits::normalize(selcx, cause, &xform_self_ty);
debug!("assemble_inherent_impl_probe: xform_self_ty = {:?}",
xform_self_ty.repr(self.tcx()));
self.inherent_candidates.push(Candidate {
xform_self_ty: xform_self_ty,
item: item,
kind: InherentImplCandidate(impl_def_id, impl_substs)
kind: InherentImplCandidate(impl_def_id, impl_substs, obligations)
});
}
@ -653,12 +663,24 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
impl_trait_ref.self_ty(),
impl_trait_ref.substs);
// Normalize the receiver. We can't use normalize_associated_types_in
// as it will pollute the fcx's fulfillment context after this probe
// is over.
let cause = traits::ObligationCause::misc(self.span, self.fcx.body_id);
let mut selcx = &mut traits::SelectionContext::new(self.fcx.infcx(), self.fcx);
let traits::Normalized { value: xform_self_ty, obligations } =
traits::normalize(selcx, cause, &xform_self_ty);
debug!("xform_self_ty={}", xform_self_ty.repr(self.tcx()));
self.extension_candidates.push(Candidate {
xform_self_ty: xform_self_ty,
item: item.clone(),
kind: ExtensionImplCandidate(impl_def_id, impl_trait_ref, impl_substs, item_index)
kind: ExtensionImplCandidate(impl_def_id,
impl_trait_ref,
impl_substs,
item_index,
obligations)
});
});
}
@ -1026,8 +1048,8 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
// match as well (or at least may match, sometimes we
// don't have enough information to fully evaluate).
match probe.kind {
InherentImplCandidate(impl_def_id, ref substs) |
ExtensionImplCandidate(impl_def_id, _, ref substs, _) => {
InherentImplCandidate(impl_def_id, ref substs, ref ref_obligations) |
ExtensionImplCandidate(impl_def_id, _, ref substs, _, ref ref_obligations) => {
let selcx = &mut traits::SelectionContext::new(self.infcx(), self.fcx);
let cause = traits::ObligationCause::misc(self.span, self.fcx.body_id);
@ -1046,8 +1068,10 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
debug!("impl_obligations={}", obligations.repr(self.tcx()));
// Evaluate those obligations to see if they might possibly hold.
obligations.iter().all(|o| selcx.evaluate_obligation(o)) &&
norm_obligations.iter().all(|o| selcx.evaluate_obligation(o))
obligations.iter()
.chain(norm_obligations.iter()).chain(ref_obligations.iter())
.all(|o| selcx.evaluate_obligation(o))
}
ProjectionCandidate(..) |
@ -1281,13 +1305,13 @@ impl<'tcx> Candidate<'tcx> {
Pick {
item: self.item.clone(),
kind: match self.kind {
InherentImplCandidate(def_id, _) => {
InherentImplCandidate(def_id, _, _) => {
InherentImplPick(def_id)
}
ObjectCandidate(def_id, item_num, real_index) => {
ObjectPick(def_id, item_num, real_index)
}
ExtensionImplCandidate(def_id, _, _, index) => {
ExtensionImplCandidate(def_id, _, _, index, _) => {
ExtensionImplPick(def_id, index)
}
ClosureCandidate(trait_def_id, index) => {
@ -1315,9 +1339,9 @@ impl<'tcx> Candidate<'tcx> {
fn to_source(&self) -> CandidateSource {
match self.kind {
InherentImplCandidate(def_id, _) => ImplSource(def_id),
InherentImplCandidate(def_id, _, _) => ImplSource(def_id),
ObjectCandidate(def_id, _, _) => TraitSource(def_id),
ExtensionImplCandidate(def_id, _, _, _) => ImplSource(def_id),
ExtensionImplCandidate(def_id, _, _, _, _) => ImplSource(def_id),
ClosureCandidate(trait_def_id, _) => TraitSource(trait_def_id),
WhereClauseCandidate(ref trait_ref, _) => TraitSource(trait_ref.def_id()),
ProjectionCandidate(trait_def_id, _) => TraitSource(trait_def_id),
@ -1335,7 +1359,7 @@ impl<'tcx> Candidate<'tcx> {
ClosureCandidate(trait_def_id, item_num) => {
Some((trait_def_id, item_num))
}
ExtensionImplCandidate(_, ref trait_ref, _, item_num) => {
ExtensionImplCandidate(_, ref trait_ref, _, item_num, _) => {
Some((trait_ref.def_id, item_num))
}
WhereClauseCandidate(ref trait_ref, item_num) => {
@ -1359,13 +1383,14 @@ impl<'tcx> Repr<'tcx> for Candidate<'tcx> {
impl<'tcx> Repr<'tcx> for CandidateKind<'tcx> {
fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
match *self {
InherentImplCandidate(ref a, ref b) =>
format!("InherentImplCandidate({},{})", a.repr(tcx), b.repr(tcx)),
InherentImplCandidate(ref a, ref b, ref c) =>
format!("InherentImplCandidate({},{},{})", a.repr(tcx), b.repr(tcx),
c.repr(tcx)),
ObjectCandidate(a, b, c) =>
format!("ObjectCandidate({},{},{})", a.repr(tcx), b, c),
ExtensionImplCandidate(ref a, ref b, ref c, ref d) =>
format!("ExtensionImplCandidate({},{},{},{})", a.repr(tcx), b.repr(tcx),
c.repr(tcx), d),
ExtensionImplCandidate(ref a, ref b, ref c, ref d, ref e) =>
format!("ExtensionImplCandidate({},{},{},{},{})", a.repr(tcx), b.repr(tcx),
c.repr(tcx), d, e.repr(tcx)),
ClosureCandidate(ref a, ref b) =>
format!("ClosureCandidate({},{})", a.repr(tcx), b),
WhereClauseCandidate(ref a, ref b) =>

36
src/test/run-pass/associated-types-method.rs Normal file
View file

@ -0,0 +1,36 @@
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Test that methods whose impl-trait-ref contains associated types
// are supported.
trait Device {
type Resources;
}
struct Foo<D, R>(D, R);
trait Tr {
fn present(&self) {}
}
impl<D: Device> Tr for Foo<D, D::Resources> {
fn present(&self) {}
}
struct Res;
struct Dev;
impl Device for Dev {
type Resources = Res;
}
fn main() {
let foo = Foo(Dev, Res);
foo.present();
}

28
src/test/run-pass/issue-25679.rs Normal file
View file

@ -0,0 +1,28 @@
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
trait Device {
type Resources;
}
struct Foo<D, R>(D, R);
impl<D: Device> Foo<D, D::Resources> {
fn present(&self) {}
}
struct Res;
struct Dev;
impl Device for Dev { type Resources = Res; }
fn main() {
let foo = Foo(Dev, Res);
foo.present();
}