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rollup merge of #22436: nikomatsakis/issue-22246-bound-lifetimes-of-assoc-types

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Take 2. This PR includes a bunch of refactoring that was part of an experimental branch implementing [implied bounds]. That particular idea isn't ready to go yet, but the refactoring proved useful for fixing #22246. The implied bounds branch also exposed #22110 so a simple fix for that is included here. I still think some more refactoring would be a good idea here -- in particular I think most of the code in wf.rs is kind of duplicating the logic in implicator and should go, but I decided to post this PR and call it a day before diving into that. I'll write a bit more details about the solutions I adopted in the various bugs. I patched the two issues I was concerned about, which was the handling of supertraits and HRTB (the latter turned out to be fine, so I added a comment explaining why.)

r? @pnkfelix (for now, anyway)
cc @aturon

[implied bounds]: http://smallcultfollowing.com/babysteps/blog/2014/07/06/implied-bounds/
This commit is contained in:
Alex Crichton 2015-02-18 14:31:58 -08:00
commit 754db0f7ac
23 changed files with 684 additions and 296 deletions
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2
src/librustc/middle/expr_use_visitor.rs
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@ -838,7 +838,7 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
// the method call infrastructure should have
// replaced all late-bound regions with variables:
let self_ty = ty::ty_fn_sig(method_ty).input(0);
let self_ty = ty::assert_no_late_bound_regions(self.tcx(), &self_ty);
let self_ty = ty::no_late_bound_regions(self.tcx(), &self_ty).unwrap();
let (m, r) = match self_ty.sty {
ty::ty_rptr(r, ref m) => (m.mutbl, r),

2
src/librustc/middle/infer/unify.rs
View File

@ -212,7 +212,7 @@ impl<K:UnifyKey> UnificationTable<K> {
}
}
impl<K> sv::SnapshotVecDelegate for Delegate<K> {
impl<K:UnifyKey> sv::SnapshotVecDelegate for Delegate<K> {
type Value = VarValue<K>;
type Undo = ();

12
src/librustc/middle/mem_categorization.rs
View File

@ -281,7 +281,6 @@ pub type McResult<T> = Result<T, ()>;
/// know that no errors have occurred, so we simply consult the tcx and we
/// can be sure that only `Ok` results will occur.
pub trait Typer<'tcx> : ty::ClosureTyper<'tcx> {
fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx>;
fn node_ty(&self, id: ast::NodeId) -> McResult<Ty<'tcx>>;
fn expr_ty_adjusted(&self, expr: &ast::Expr) -> McResult<Ty<'tcx>>;
fn type_moves_by_default(&self, span: Span, ty: Ty<'tcx>) -> bool;
@ -905,8 +904,8 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
let base_cmt = match method_ty {
Some(method_ty) => {
let ref_ty =
ty::assert_no_late_bound_regions(
self.tcx(), &ty::ty_fn_ret(method_ty)).unwrap();
ty::no_late_bound_regions(
self.tcx(), &ty::ty_fn_ret(method_ty)).unwrap().unwrap();
self.cat_rvalue_node(node.id(), node.span(), ref_ty)
}
None => base_cmt
@ -996,7 +995,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
// FIXME(#20649) -- why are we using the `self_ty` as the element type...?
let self_ty = ty::ty_fn_sig(method_ty).input(0);
ty::assert_no_late_bound_regions(self.tcx(), &self_ty)
ty::no_late_bound_regions(self.tcx(), &self_ty).unwrap()
}
None => {
match ty::array_element_ty(self.tcx(), base_cmt.ty) {
@ -1336,8 +1335,9 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
// types are generated by method resolution and always have
// all late-bound regions fully instantiated, so we just want
// to skip past the binder.
ty::assert_no_late_bound_regions(self.tcx(), &ty::ty_fn_ret(method_ty))
.unwrap() // overloaded ops do not diverge, either
ty::no_late_bound_regions(self.tcx(), &ty::ty_fn_ret(method_ty))
.unwrap()
.unwrap() // overloaded ops do not diverge, either
}
}

1
src/librustc/middle/traits/fulfill.rs
View File

@ -9,7 +9,6 @@
// except according to those terms.
use middle::infer::{InferCtxt};
use middle::mem_categorization::Typer;
use middle::ty::{self, RegionEscape, Ty};
use std::collections::HashSet;
use std::collections::hash_map::Entry::{Occupied, Vacant};

47
src/librustc/middle/traits/mod.rs
View File

@ -15,9 +15,9 @@ pub use self::FulfillmentErrorCode::*;
pub use self::Vtable::*;
pub use self::ObligationCauseCode::*;
use middle::mem_categorization::Typer;
use middle::subst;
use middle::ty::{self, Ty};
use middle::ty::{self, HasProjectionTypes, Ty};
use middle::ty_fold::TypeFoldable;
use middle::infer::{self, InferCtxt};
use std::slice::Iter;
use std::rc::Rc;
@ -432,18 +432,8 @@ pub fn normalize_param_env<'a,'tcx>(param_env: &ty::ParameterEnvironment<'a,'tcx
debug!("normalize_param_env(param_env={})",
param_env.repr(tcx));
let predicates: Vec<ty::Predicate<'tcx>> = {
let infcx = infer::new_infer_ctxt(tcx);
let mut selcx = &mut SelectionContext::new(&infcx, param_env);
let mut fulfill_cx = FulfillmentContext::new();
let Normalized { value: predicates, obligations } =
project::normalize(selcx, cause, &param_env.caller_bounds);
for obligation in obligations {
fulfill_cx.register_predicate_obligation(selcx.infcx(), obligation);
}
try!(fulfill_cx.select_all_or_error(selcx.infcx(), param_env));
predicates.iter().map(|p| infcx.resolve_type_vars_if_possible(p)).collect()
};
let infcx = infer::new_infer_ctxt(tcx);
let predicates = try!(fully_normalize(&infcx, param_env, cause, &param_env.caller_bounds));
debug!("normalize_param_env: predicates={}",
predicates.repr(tcx));
@ -451,6 +441,35 @@ pub fn normalize_param_env<'a,'tcx>(param_env: &ty::ParameterEnvironment<'a,'tcx
Ok(param_env.with_caller_bounds(predicates))
}
pub fn fully_normalize<'a,'tcx,T>(infcx: &InferCtxt<'a,'tcx>,
closure_typer: &ty::ClosureTyper<'tcx>,
cause: ObligationCause<'tcx>,
value: &T)
-> Result<T, Vec<FulfillmentError<'tcx>>>
where T : TypeFoldable<'tcx> + HasProjectionTypes + Clone + Repr<'tcx>
{
let tcx = closure_typer.tcx();
debug!("normalize_param_env(value={})",
value.repr(tcx));
let mut selcx = &mut SelectionContext::new(infcx, closure_typer);
let mut fulfill_cx = FulfillmentContext::new();
let Normalized { value: normalized_value, obligations } =
project::normalize(selcx, cause, value);
debug!("normalize_param_env: normalized_value={} obligations={}",
normalized_value.repr(tcx),
obligations.repr(tcx));
for obligation in obligations {
fulfill_cx.register_predicate_obligation(selcx.infcx(), obligation);
}
try!(fulfill_cx.select_all_or_error(infcx, closure_typer));
let resolved_value = infcx.resolve_type_vars_if_possible(&normalized_value);
debug!("normalize_param_env: resolved_value={}",
resolved_value.repr(tcx));
Ok(resolved_value)
}
impl<'tcx,O> Obligation<'tcx,O> {
pub fn new(cause: ObligationCause<'tcx>,
trait_ref: O)

72
src/librustc/middle/traits/select.rs
View File

@ -32,7 +32,6 @@ use super::object_safety;
use super::{util};
use middle::fast_reject;
use middle::mem_categorization::Typer;
use middle::subst::{Subst, Substs, TypeSpace, VecPerParamSpace};
use middle::ty::{self, RegionEscape, ToPolyTraitRef, Ty};
use middle::infer;
@ -653,8 +652,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let is_dup =
(0..candidates.len())
.filter(|&j| i != j)
.any(|j| self.candidate_should_be_dropped_in_favor_of(stack,
&candidates[i],
.any(|j| self.candidate_should_be_dropped_in_favor_of(&candidates[i],
&candidates[j]));
if is_dup {
debug!("Dropping candidate #{}/{}: {}",
@ -1236,31 +1234,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
self.evaluate_predicates_recursively(stack, selection.iter_nested())
}
/// Returns true if `candidate_i` should be dropped in favor of `candidate_j`.
///
/// This is generally true if either:
/// - candidate i and candidate j are equivalent; or,
/// - candidate i is a concrete impl and candidate j is a where clause bound,
/// and the concrete impl is applicable to the types in the where clause bound.
///
/// The last case refers to cases where there are blanket impls (often conditional
/// blanket impls) as well as a where clause. This can come down to one of two cases:
///
/// - The impl is truly unconditional (it has no where clauses
/// of its own), in which case the where clause is
/// unnecessary, because coherence requires that we would
/// pick that particular impl anyhow (at least so long as we
/// don't have specialization).
///
/// - The impl is conditional, in which case we may not have winnowed it out
/// because we don't know if the conditions apply, but the where clause is basically
/// telling us that there is some impl, though not necessarily the one we see.
///
/// In both cases we prefer to take the where clause, which is
/// essentially harmless. See issue #18453 for more details of
/// a case where doing the opposite caused us harm.
/// Returns true if `candidate_i` should be dropped in favor of
/// `candidate_j`. Generally speaking we will drop duplicate
/// candidates and prefer where-clause candidates.
fn candidate_should_be_dropped_in_favor_of<'o>(&mut self,
stack: &TraitObligationStack<'o, 'tcx>,
candidate_i: &SelectionCandidate<'tcx>,
candidate_j: &SelectionCandidate<'tcx>)
-> bool
@ -1270,37 +1247,16 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
match (candidate_i, candidate_j) {
(&ImplCandidate(impl_def_id), &ParamCandidate(ref bound)) => {
debug!("Considering whether to drop param {} in favor of impl {}",
candidate_i.repr(self.tcx()),
candidate_j.repr(self.tcx()));
self.infcx.probe(|snapshot| {
let (skol_obligation_trait_ref, skol_map) =
self.infcx().skolemize_late_bound_regions(
&stack.obligation.predicate, snapshot);
let impl_substs =
self.rematch_impl(impl_def_id, stack.obligation, snapshot,
&skol_map, skol_obligation_trait_ref.trait_ref.clone());
let impl_trait_ref =
ty::impl_trait_ref(self.tcx(), impl_def_id).unwrap();
let impl_trait_ref =
impl_trait_ref.subst(self.tcx(), &impl_substs.value);
let poly_impl_trait_ref =
ty::Binder(impl_trait_ref);
let origin =
infer::RelateOutputImplTypes(stack.obligation.cause.span);
self.infcx
.sub_poly_trait_refs(false, origin, poly_impl_trait_ref, bound.clone())
.is_ok()
})
}
(&BuiltinCandidate(_), &ParamCandidate(_)) => {
// If we have a where-clause like `Option<K> : Send`,
// then we wind up in a situation where there is a
// default rule (`Option<K>:Send if K:Send) and the
// where-clause that both seem applicable. Just take
// the where-clause in that case.
(&ImplCandidate(..), &ParamCandidate(..)) |
(&ClosureCandidate(..), &ParamCandidate(..)) |
(&FnPointerCandidate(..), &ParamCandidate(..)) |
(&BuiltinCandidate(..), &ParamCandidate(..)) => {
// We basically prefer always prefer to use a
// where-clause over another option. Where clauses
// impose the burden of finding the exact match onto
// the caller. Using an impl in preference of a where
// clause can also lead us to "overspecialize", as in
// #18453.
true
}
(&ProjectionCandidate, &ParamCandidate(_)) => {

25
src/librustc/middle/ty.rs
View File

@ -2337,6 +2337,10 @@ impl ClosureKind {
}
pub trait ClosureTyper<'tcx> {
fn tcx(&self) -> &ty::ctxt<'tcx> {
self.param_env().tcx
}
fn param_env<'a>(&'a self) -> &'a ty::ParameterEnvironment<'a, 'tcx>;
/// Is this a `Fn`, `FnMut` or `FnOnce` closure? During typeck,
@ -4384,8 +4388,8 @@ pub fn adjust_ty<'tcx, F>(cx: &ctxt<'tcx>,
// overloaded deref operators have all late-bound
// regions fully instantiated and coverge
let fn_ret =
ty::assert_no_late_bound_regions(cx,
&ty_fn_ret(method_ty));
ty::no_late_bound_regions(cx,
&ty_fn_ret(method_ty)).unwrap();
adjusted_ty = fn_ret.unwrap();
}
None => {}
@ -5186,7 +5190,7 @@ impl<'tcx> VariantInfo<'tcx> {
let arg_tys = if args.len() > 0 {
// the regions in the argument types come from the
// enum def'n, and hence will all be early bound
ty::assert_no_late_bound_regions(cx, &ty_fn_args(ctor_ty))
ty::no_late_bound_regions(cx, &ty_fn_args(ctor_ty)).unwrap()
} else {
Vec::new()
};
@ -6463,10 +6467,6 @@ impl<'tcx> ctxt<'tcx> {
}
impl<'a,'tcx> mc::Typer<'tcx> for ParameterEnvironment<'a,'tcx> {
fn tcx(&self) -> &ty::ctxt<'tcx> {
self.tcx
}
fn node_ty(&self, id: ast::NodeId) -> mc::McResult<Ty<'tcx>> {
Ok(ty::node_id_to_type(self.tcx, id))
}
@ -6677,14 +6677,17 @@ pub fn binds_late_bound_regions<'tcx, T>(
count_late_bound_regions(tcx, value) > 0
}
pub fn assert_no_late_bound_regions<'tcx, T>(
pub fn no_late_bound_regions<'tcx, T>(
tcx: &ty::ctxt<'tcx>,
value: &Binder<T>)
-> T
-> Option<T>
where T : TypeFoldable<'tcx> + Repr<'tcx> + Clone
{
assert!(!binds_late_bound_regions(tcx, value));
value.0.clone()
if binds_late_bound_regions(tcx, value) {
None
} else {
Some(value.0.clone())
}
}
/// Replace any late-bound regions bound in `value` with `'static`. Useful in trans but also

1
src/librustc_borrowck/borrowck/gather_loans/gather_moves.rs
View File

@ -16,7 +16,6 @@ use borrowck::gather_loans::move_error::{MoveError, MoveErrorCollector};
use borrowck::move_data::*;
use rustc::middle::expr_use_visitor as euv;
use rustc::middle::mem_categorization as mc;
use rustc::middle::mem_categorization::Typer;
use rustc::middle::mem_categorization::InteriorOffsetKind as Kind;
use rustc::middle::ty;
use rustc::util::ppaux::Repr;

1
src/librustc_borrowck/borrowck/gather_loans/move_error.rs
View File

@ -10,7 +10,6 @@
use borrowck::BorrowckCtxt;
use rustc::middle::mem_categorization as mc;
use rustc::middle::mem_categorization::Typer;
use rustc::middle::mem_categorization::InteriorOffsetKind as Kind;
use rustc::middle::ty;
use rustc::util::ppaux::UserString;

4
src/librustc_trans/trans/common.rs
View File

@ -637,10 +637,6 @@ impl<'blk, 'tcx> BlockS<'blk, 'tcx> {
}
impl<'blk, 'tcx> mc::Typer<'tcx> for BlockS<'blk, 'tcx> {
fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx> {
self.tcx()
}
fn node_ty(&self, id: ast::NodeId) -> mc::McResult<Ty<'tcx>> {
Ok(node_id_type(self, id))
}

8
src/librustc_trans/trans/expr.rs
View File

@ -781,8 +781,8 @@ fn trans_index<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
let ix_datum = unpack_datum!(bcx, trans(bcx, idx));
let ref_ty = // invoked methods have LB regions instantiated:
ty::assert_no_late_bound_regions(
bcx.tcx(), &ty::ty_fn_ret(method_ty)).unwrap();
ty::no_late_bound_regions(
bcx.tcx(), &ty::ty_fn_ret(method_ty)).unwrap().unwrap();
let elt_ty = match ty::deref(ref_ty, true) {
None => {
bcx.tcx().sess.span_bug(index_expr.span,
@ -2214,8 +2214,8 @@ fn deref_once<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
};
let ref_ty = // invoked methods have their LB regions instantiated
ty::assert_no_late_bound_regions(
ccx.tcx(), &ty::ty_fn_ret(method_ty)).unwrap();
ty::no_late_bound_regions(
ccx.tcx(), &ty::ty_fn_ret(method_ty)).unwrap().unwrap();
let scratch = rvalue_scratch_datum(bcx, ref_ty, "overloaded_deref");
unpack_result!(bcx, trans_overloaded_op(bcx, expr, method_call,

2
src/librustc_typeck/check/_match.rs
View File

@ -509,7 +509,7 @@ pub fn check_pat_enum<'a, 'tcx>(pcx: &pat_ctxt<'a, 'tcx>,
let ctor_scheme = ty::lookup_item_type(tcx, enum_def);
let ctor_predicates = ty::lookup_predicates(tcx, enum_def);
let path_scheme = if ty::is_fn_ty(ctor_scheme.ty) {
let fn_ret = ty::assert_no_late_bound_regions(tcx, &ty::ty_fn_ret(ctor_scheme.ty));
let fn_ret = ty::no_late_bound_regions(tcx, &ty::ty_fn_ret(ctor_scheme.ty)).unwrap();
ty::TypeScheme {
ty: fn_ret.unwrap(),
generics: ctor_scheme.generics,

4
src/librustc_typeck/check/callee.rs
View File

@ -367,8 +367,8 @@ impl<'tcx> DeferredCallResolution<'tcx> for CallResolution<'tcx> {
// (This always bites me, should find a way to
// refactor it.)
let method_sig =
ty::assert_no_late_bound_regions(fcx.tcx(),
ty::ty_fn_sig(method_callee.ty));
ty::no_late_bound_regions(fcx.tcx(),
ty::ty_fn_sig(method_callee.ty)).unwrap();
debug!("attempt_resolution: method_callee={}",
method_callee.repr(fcx.tcx()));

294
src/librustc_typeck/check/regionmanip.rs → src/librustc_typeck/check/implicator.rs
View File

@ -10,52 +10,74 @@
// #![warn(deprecated_mode)]
pub use self::WfConstraint::*;
use astconv::object_region_bounds;
use middle::infer::GenericKind;
use middle::subst::{ParamSpace, Subst, Substs};
use middle::ty::{self, Ty};
use middle::ty_fold::{TypeFolder};
use middle::infer::{InferCtxt, GenericKind};
use middle::subst::{Substs};
use middle::traits;
use middle::ty::{self, ToPolyTraitRef, Ty};
use middle::ty_fold::{TypeFoldable, TypeFolder};
use std::rc::Rc;
use syntax::ast;
use syntax::codemap::Span;
use util::common::ErrorReported;
use util::ppaux::Repr;
// Helper functions related to manipulating region types.
pub enum WfConstraint<'tcx> {
RegionSubRegionConstraint(Option<Ty<'tcx>>, ty::Region, ty::Region),
RegionSubGenericConstraint(Option<Ty<'tcx>>, ty::Region, GenericKind<'tcx>),
pub enum Implication<'tcx> {
RegionSubRegion(Option<Ty<'tcx>>, ty::Region, ty::Region),
RegionSubGeneric(Option<Ty<'tcx>>, ty::Region, GenericKind<'tcx>),
Predicate(ast::DefId, ty::Predicate<'tcx>),
}
struct Wf<'a, 'tcx: 'a> {
tcx: &'a ty::ctxt<'tcx>,
struct Implicator<'a, 'tcx: 'a> {
infcx: &'a InferCtxt<'a,'tcx>,
closure_typer: &'a (ty::ClosureTyper<'tcx>+'a),
body_id: ast::NodeId,
stack: Vec<(ty::Region, Option<Ty<'tcx>>)>,
out: Vec<WfConstraint<'tcx>>,
span: Span,
out: Vec<Implication<'tcx>>,
}
/// This routine computes the well-formedness constraints that must hold for the type `ty` to
/// appear in a context with lifetime `outer_region`
pub fn region_wf_constraints<'tcx>(
tcx: &ty::ctxt<'tcx>,
pub fn implications<'a,'tcx>(
infcx: &'a InferCtxt<'a,'tcx>,
closure_typer: &ty::ClosureTyper<'tcx>,
body_id: ast::NodeId,
ty: Ty<'tcx>,
outer_region: ty::Region)
-> Vec<WfConstraint<'tcx>>
outer_region: ty::Region,
span: Span)
-> Vec<Implication<'tcx>>
{
debug!("implications(body_id={}, ty={}, outer_region={})",
body_id,
ty.repr(closure_typer.tcx()),
outer_region.repr(closure_typer.tcx()));
let mut stack = Vec::new();
stack.push((outer_region, None));
let mut wf = Wf { tcx: tcx,
stack: stack,
out: Vec::new() };
let mut wf = Implicator { closure_typer: closure_typer,
infcx: infcx,
body_id: body_id,
span: span,
stack: stack,
out: Vec::new() };
wf.accumulate_from_ty(ty);
debug!("implications: out={}", wf.out.repr(closure_typer.tcx()));
wf.out
}
impl<'a, 'tcx> Wf<'a, 'tcx> {
impl<'a, 'tcx> Implicator<'a, 'tcx> {
fn tcx(&self) -> &'a ty::ctxt<'tcx> {
self.infcx.tcx
}
fn accumulate_from_ty(&mut self, ty: Ty<'tcx>) {
debug!("Wf::accumulate_from_ty(ty={})",
ty.repr(self.tcx));
debug!("accumulate_from_ty(ty={})",
ty.repr(self.tcx()));
match ty.sty {
ty::ty_bool |
@ -96,13 +118,13 @@ impl<'a, 'tcx> Wf<'a, 'tcx> {
ty::ty_trait(ref t) => {
let required_region_bounds =
object_region_bounds(self.tcx, &t.principal, t.bounds.builtin_bounds);
object_region_bounds(self.tcx(), &t.principal, t.bounds.builtin_bounds);
self.accumulate_from_object_ty(ty, t.bounds.region_bound, required_region_bounds)
}
ty::ty_enum(def_id, substs) |
ty::ty_struct(def_id, substs) => {
let item_scheme = ty::lookup_item_type(self.tcx, def_id);
let item_scheme = ty::lookup_item_type(self.tcx(), def_id);
self.accumulate_from_adt(ty, def_id, &item_scheme.generics, substs)
}
@ -141,9 +163,9 @@ impl<'a, 'tcx> Wf<'a, 'tcx> {
}
ty::ty_open(_) => {
self.tcx.sess.bug(
self.tcx().sess.bug(
&format!("Unexpected type encountered while doing wf check: {}",
ty.repr(self.tcx))[]);
ty.repr(self.tcx()))[]);
}
}
}
@ -197,7 +219,7 @@ impl<'a, 'tcx> Wf<'a, 'tcx> {
opt_ty: Option<Ty<'tcx>>,
r_a: ty::Region,
r_b: ty::Region) {
self.out.push(RegionSubRegionConstraint(opt_ty, r_a, r_b));
self.out.push(Implication::RegionSubRegion(opt_ty, r_a, r_b));
}
/// Pushes a constraint that `param_ty` must outlive the top region on the stack.
@ -211,7 +233,7 @@ impl<'a, 'tcx> Wf<'a, 'tcx> {
fn push_projection_constraint_from_top(&mut self,
projection_ty: &ty::ProjectionTy<'tcx>) {
let &(region, opt_ty) = self.stack.last().unwrap();
self.out.push(RegionSubGenericConstraint(
self.out.push(Implication::RegionSubGeneric(
opt_ty, region, GenericKind::Projection(projection_ty.clone())));
}
@ -220,108 +242,118 @@ impl<'a, 'tcx> Wf<'a, 'tcx> {
region: ty::Region,
opt_ty: Option<Ty<'tcx>>,
param_ty: ty::ParamTy) {
self.out.push(RegionSubGenericConstraint(
self.out.push(Implication::RegionSubGeneric(
opt_ty, region, GenericKind::Param(param_ty)));
}
fn accumulate_from_adt(&mut self,
ty: Ty<'tcx>,
def_id: ast::DefId,
generics: &ty::Generics<'tcx>,
_generics: &ty::Generics<'tcx>,
substs: &Substs<'tcx>)
{
// The generic declarations from the type, appropriately
// substituted for the actual substitutions.
let generics = generics.subst(self.tcx, substs);
let predicates =
ty::lookup_predicates(self.tcx(), def_id).instantiate(self.tcx(), substs);
let predicates = match self.fully_normalize(&predicates) {
Ok(predicates) => predicates,
Err(ErrorReported) => { return; }
};
// Variance of each type/region parameter.
let variances = ty::item_variances(self.tcx, def_id);
for &space in &ParamSpace::all() {
let region_params = substs.regions().get_slice(space);
let region_variances = variances.regions.get_slice(space);
let region_param_defs = generics.regions.get_slice(space);
assert_eq!(region_params.len(), region_variances.len());
for (&region_param, (&region_variance, region_param_def)) in
region_params.iter().zip(
region_variances.iter().zip(
region_param_defs.iter()))
{
match region_variance {
ty::Covariant | ty::Bivariant => {
// Ignore covariant or bivariant region
// parameters. To understand why, consider a
// struct `Foo<'a>`. If `Foo` contains any
// references with lifetime `'a`, then `'a` must
// be at least contravariant (and possibly
// invariant). The only way to have a covariant
// result is if `Foo` contains only a field with a
// type like `fn() -> &'a T`; i.e., a bare
// function that can produce a reference of
// lifetime `'a`. In this case, there is no
// *actual data* with lifetime `'a` that is
// reachable. (Presumably this bare function is
// really returning static data.)
}
ty::Contravariant | ty::Invariant => {
// If the parameter is contravariant or
// invariant, there may indeed be reachable
// data with this lifetime. See other case for
// more details.
self.push_region_constraint_from_top(region_param);
for predicate in predicates.predicates.as_slice() {
match *predicate {
ty::Predicate::Trait(ref data) => {
self.accumulate_from_assoc_types_transitive(data);
}
ty::Predicate::Equate(..) => { }
ty::Predicate::Projection(..) => { }
ty::Predicate::RegionOutlives(ref data) => {
match ty::no_late_bound_regions(self.tcx(), data) {
None => { }
Some(ty::OutlivesPredicate(r_a, r_b)) => {
self.push_sub_region_constraint(Some(ty), r_b, r_a);
}
}
}
for &region_bound in &region_param_def.bounds {
// The type declared a constraint like
//
// 'b : 'a
//
// which means that `'a <= 'b` (after
// substitution). So take the region we
// substituted for `'a` (`region_bound`) and make
// it a subregion of the region we substituted
// `'b` (`region_param`).
self.push_sub_region_constraint(
Some(ty), region_bound, region_param);
ty::Predicate::TypeOutlives(ref data) => {
match ty::no_late_bound_regions(self.tcx(), data) {
None => { }
Some(ty::OutlivesPredicate(ty_a, r_b)) => {
self.stack.push((r_b, Some(ty)));
self.accumulate_from_ty(ty_a);
self.stack.pop().unwrap();
}
}
}
}
}
let types = substs.types.get_slice(space);
let type_variances = variances.types.get_slice(space);
let type_param_defs = generics.types.get_slice(space);
assert_eq!(types.len(), type_variances.len());
for (&type_param_ty, (&variance, type_param_def)) in
types.iter().zip(
type_variances.iter().zip(
type_param_defs.iter()))
{
debug!("type_param_ty={} variance={}",
type_param_ty.repr(self.tcx),
variance.repr(self.tcx));
let obligations = predicates.predicates
.into_iter()
.map(|pred| Implication::Predicate(def_id, pred));
self.out.extend(obligations);
match variance {
ty::Contravariant | ty::Bivariant => {
// As above, except that in this it is a
// *contravariant* reference that indices that no
// actual data of type T is reachable.
}
let variances = ty::item_variances(self.tcx(), def_id);
ty::Covariant | ty::Invariant => {
self.accumulate_from_ty(type_param_ty);
}
}
// Inspect bounds on this type parameter for any
// region bounds.
for &r in &type_param_def.bounds.region_bounds {
self.stack.push((r, Some(ty)));
self.accumulate_from_ty(type_param_ty);
self.stack.pop().unwrap();
for (&region, &variance) in substs.regions().iter().zip(variances.regions.iter()) {
match variance {
ty::Contravariant | ty::Invariant => {
// If any data with this lifetime is reachable
// within, it must be at least contravariant.
self.push_region_constraint_from_top(region)
}
ty::Covariant | ty::Bivariant => { }
}
}
for (&ty, &variance) in substs.types.iter().zip(variances.types.iter()) {
match variance {
ty::Covariant | ty::Invariant => {
// If any data of this type is reachable within,
// it must be at least covariant.
self.accumulate_from_ty(ty);
}
ty::Contravariant | ty::Bivariant => { }
}
}
}
/// Given that there is a requirement that `Foo<X> : 'a`, where
/// `Foo` is declared like `struct Foo<T> where T : SomeTrait`,
/// this code finds all the associated types defined in
/// `SomeTrait` (and supertraits) and adds a requirement that `<X
/// as SomeTrait>::N : 'a` (where `N` is some associated type
/// defined in `SomeTrait`). This rule only applies to
/// trait-bounds that are not higher-ranked, because we cannot
/// project out of a HRTB. This rule helps code using associated
/// types to compile, see Issue #22246 for an example.
fn accumulate_from_assoc_types_transitive(&mut self,
data: &ty::PolyTraitPredicate<'tcx>)
{
for poly_trait_ref in traits::supertraits(self.tcx(), data.to_poly_trait_ref()) {
match ty::no_late_bound_regions(self.tcx(), &poly_trait_ref) {
Some(trait_ref) => { self.accumulate_from_assoc_types(trait_ref); }
None => { }
}
}
}
fn accumulate_from_assoc_types(&mut self,
trait_ref: Rc<ty::TraitRef<'tcx>>)
{
let trait_def_id = trait_ref.def_id;
let trait_def = ty::lookup_trait_def(self.tcx(), trait_def_id);
let assoc_type_projections: Vec<_> =
trait_def.associated_type_names
.iter()
.map(|&name| ty::mk_projection(self.tcx(), trait_ref.clone(), name))
.collect();
let tys = match self.fully_normalize(&assoc_type_projections) {
Ok(tys) => { tys }
Err(ErrorReported) => { return; }
};
for ty in tys {
self.accumulate_from_ty(ty);
}
}
fn accumulate_from_object_ty(&mut self,
@ -372,25 +404,53 @@ impl<'a, 'tcx> Wf<'a, 'tcx> {
for &r_d in &required_region_bounds {
// Each of these is an instance of the `'c <= 'b`
// constraint above
self.out.push(RegionSubRegionConstraint(Some(ty), r_d, r_c));
self.out.push(Implication::RegionSubRegion(Some(ty), r_d, r_c));
}
}
fn fully_normalize<T>(&self, value: &T) -> Result<T,ErrorReported>
where T : TypeFoldable<'tcx> + ty::HasProjectionTypes + Clone + Repr<'tcx>
{
let value =
traits::fully_normalize(self.infcx,
self.closure_typer,
traits::ObligationCause::misc(self.span, self.body_id),
value);
match value {
Ok(value) => Ok(value),
Err(errors) => {
// I don't like reporting these errors here, but I
// don't know where else to report them just now. And
// I don't really expect errors to arise here
// frequently. I guess the best option would be to
// propagate them out.
traits::report_fulfillment_errors(self.infcx, &errors);
Err(ErrorReported)
}
}
}
}
impl<'tcx> Repr<'tcx> for WfConstraint<'tcx> {
impl<'tcx> Repr<'tcx> for Implication<'tcx> {
fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
match *self {
RegionSubRegionConstraint(_, ref r_a, ref r_b) => {
format!("RegionSubRegionConstraint({}, {})",
Implication::RegionSubRegion(_, ref r_a, ref r_b) => {
format!("RegionSubRegion({}, {})",
r_a.repr(tcx),
r_b.repr(tcx))
}
RegionSubGenericConstraint(_, ref r, ref p) => {
format!("RegionSubGenericConstraint({}, {})",
Implication::RegionSubGeneric(_, ref r, ref p) => {
format!("RegionSubGeneric({}, {})",
r.repr(tcx),
p.repr(tcx))
}
Implication::Predicate(ref def_id, ref p) => {
format!("Predicate({}, {})",
def_id.repr(tcx),
p.repr(tcx))
}
}
}
}

23
src/librustc_typeck/check/mod.rs
View File

@ -131,7 +131,7 @@ pub mod dropck;
pub mod _match;
pub mod vtable;
pub mod writeback;
pub mod regionmanip;
pub mod implicator;
pub mod regionck;
pub mod coercion;
pub mod demand;
@ -309,9 +309,6 @@ pub struct FnCtxt<'a, 'tcx: 'a> {
}
impl<'a, 'tcx> mc::Typer<'tcx> for FnCtxt<'a, 'tcx> {
fn tcx(&self) -> &ty::ctxt<'tcx> {
self.ccx.tcx
}
fn node_ty(&self, id: ast::NodeId) -> McResult<Ty<'tcx>> {
let ty = self.node_ty(id);
self.resolve_type_vars_or_error(&ty)
@ -484,7 +481,8 @@ pub fn check_item_types(ccx: &CrateCtxt) {
fn check_bare_fn<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
decl: &'tcx ast::FnDecl,
body: &'tcx ast::Block,
id: ast::NodeId,
fn_id: ast::NodeId,
fn_span: Span,
raw_fty: Ty<'tcx>,
param_env: ty::ParameterEnvironment<'a, 'tcx>)
{
@ -502,13 +500,13 @@ fn check_bare_fn<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
let fn_sig =
inh.normalize_associated_types_in(&inh.param_env, body.span, body.id, &fn_sig);
let fcx = check_fn(ccx, fn_ty.unsafety, id, &fn_sig,
decl, id, body, &inh);
let fcx = check_fn(ccx, fn_ty.unsafety, fn_id, &fn_sig,
decl, fn_id, body, &inh);
vtable::select_all_fcx_obligations_and_apply_defaults(&fcx);
upvar::closure_analyze_fn(&fcx, id, decl, body);
upvar::closure_analyze_fn(&fcx, fn_id, decl, body);
vtable::select_all_fcx_obligations_or_error(&fcx);
regionck::regionck_fn(&fcx, id, decl, body);
regionck::regionck_fn(&fcx, fn_id, fn_span, decl, body);
writeback::resolve_type_vars_in_fn(&fcx, decl, body);
}
_ => ccx.tcx.sess.impossible_case(body.span,
@ -721,7 +719,7 @@ pub fn check_item<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>, it: &'tcx ast::Item) {
ast::ItemFn(ref decl, _, _, _, ref body) => {
let fn_pty = ty::lookup_item_type(ccx.tcx, ast_util::local_def(it.id));
let param_env = ParameterEnvironment::for_item(ccx.tcx, it.id);
check_bare_fn(ccx, &**decl, &**body, it.id, fn_pty.ty, param_env);
check_bare_fn(ccx, &**decl, &**body, it.id, it.span, fn_pty.ty, param_env);
}
ast::ItemImpl(_, _, _, _, _, ref impl_items) => {
debug!("ItemImpl {} with id {}", token::get_ident(it.ident), it.id);
@ -868,6 +866,7 @@ fn check_method_body<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
&*method.pe_fn_decl(),
&*method.pe_body(),
method.id,
method.span,
fty,
param_env);
}
@ -2050,8 +2049,8 @@ fn make_overloaded_lvalue_return_type<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
match method {
Some(method) => {
let ref_ty = // invoked methods have all LB regions instantiated
ty::assert_no_late_bound_regions(
fcx.tcx(), &ty::ty_fn_ret(method.ty));
ty::no_late_bound_regions(
fcx.tcx(), &ty::ty_fn_ret(method.ty)).unwrap();
match method_call {
Some(method_call) => {
fcx.inh.method_map.borrow_mut().insert(method_call,

128
src/librustc_typeck/check/regionck.rs
View File

@ -85,7 +85,7 @@
use astconv::AstConv;
use check::dropck;
use check::FnCtxt;
use check::regionmanip;
use check::implicator;
use check::vtable;
use middle::def;
use middle::mem_categorization as mc;
@ -97,12 +97,12 @@ use middle::infer::{self, GenericKind};
use middle::pat_util;
use util::ppaux::{ty_to_string, Repr};
use std::mem;
use syntax::{ast, ast_util};
use syntax::codemap::Span;
use syntax::visit;
use syntax::visit::Visitor;
use self::RepeatingScope::Repeating;
use self::SubjectNode::Subject;
// a variation on try that just returns unit
@ -114,7 +114,7 @@ macro_rules! ignore_err {
// PUBLIC ENTRY POINTS
pub fn regionck_expr(fcx: &FnCtxt, e: &ast::Expr) {
let mut rcx = Rcx::new(fcx, Repeating(e.id), Subject(e.id));
let mut rcx = Rcx::new(fcx, RepeatingScope(e.id), e.id, Subject(e.id));
if fcx.err_count_since_creation() == 0 {
// regionck assumes typeck succeeded
rcx.visit_expr(e);
@ -124,22 +124,23 @@ pub fn regionck_expr(fcx: &FnCtxt, e: &ast::Expr) {
}
pub fn regionck_item(fcx: &FnCtxt, item: &ast::Item) {
let mut rcx = Rcx::new(fcx, Repeating(item.id), Subject(item.id));
let mut rcx = Rcx::new(fcx, RepeatingScope(item.id), item.id, Subject(item.id));
rcx.visit_region_obligations(item.id);
rcx.resolve_regions_and_report_errors();
}
pub fn regionck_fn(fcx: &FnCtxt, id: ast::NodeId, decl: &ast::FnDecl, blk: &ast::Block) {
let mut rcx = Rcx::new(fcx, Repeating(blk.id), Subject(id));
pub fn regionck_fn(fcx: &FnCtxt,
fn_id: ast::NodeId,
fn_span: Span,
decl: &ast::FnDecl,
blk: &ast::Block) {
debug!("regionck_fn(id={})", fn_id);
let mut rcx = Rcx::new(fcx, RepeatingScope(blk.id), blk.id, Subject(fn_id));
if fcx.err_count_since_creation() == 0 {
// regionck assumes typeck succeeded
rcx.visit_fn_body(id, decl, blk);
rcx.visit_fn_body(fn_id, decl, blk, fn_span);
}
// Region checking a fn can introduce new trait obligations,
// particularly around closure bounds.
vtable::select_all_fcx_obligations_or_error(fcx);
rcx.resolve_regions_and_report_errors();
}
@ -148,7 +149,7 @@ pub fn regionck_fn(fcx: &FnCtxt, id: ast::NodeId, decl: &ast::FnDecl, blk: &ast:
pub fn regionck_ensure_component_tys_wf<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
span: Span,
component_tys: &[Ty<'tcx>]) {
let mut rcx = Rcx::new(fcx, Repeating(0), SubjectNode::None);
let mut rcx = Rcx::new(fcx, RepeatingScope(0), 0, SubjectNode::None);
for &component_ty in component_tys {
// Check that each type outlives the empty region. Since the
// empty region is a subregion of all others, this can't fail
@ -167,6 +168,9 @@ pub struct Rcx<'a, 'tcx: 'a> {
region_bound_pairs: Vec<(ty::Region, GenericKind<'tcx>)>,
// id of innermost fn body id
body_id: ast::NodeId,
// id of innermost fn or loop
repeating_scope: ast::NodeId,
@ -189,16 +193,18 @@ fn region_of_def(fcx: &FnCtxt, def: def::Def) -> ty::Region {
}
}
pub enum RepeatingScope { Repeating(ast::NodeId) }
struct RepeatingScope(ast::NodeId);
pub enum SubjectNode { Subject(ast::NodeId), None }
impl<'a, 'tcx> Rcx<'a, 'tcx> {
pub fn new(fcx: &'a FnCtxt<'a, 'tcx>,
initial_repeating_scope: RepeatingScope,
initial_body_id: ast::NodeId,
subject: SubjectNode) -> Rcx<'a, 'tcx> {
let Repeating(initial_repeating_scope) = initial_repeating_scope;
let RepeatingScope(initial_repeating_scope) = initial_repeating_scope;
Rcx { fcx: fcx,
repeating_scope: initial_repeating_scope,
body_id: initial_body_id,
subject: subject,
region_bound_pairs: Vec::new()
}
@ -208,10 +214,12 @@ impl<'a, 'tcx> Rcx<'a, 'tcx> {
self.fcx.ccx.tcx
}
pub fn set_repeating_scope(&mut self, scope: ast::NodeId) -> ast::NodeId {
let old_scope = self.repeating_scope;
self.repeating_scope = scope;
old_scope
fn set_body_id(&mut self, body_id: ast::NodeId) -> ast::NodeId {
mem::replace(&mut self.body_id, body_id)
}
fn set_repeating_scope(&mut self, scope: ast::NodeId) -> ast::NodeId {
mem::replace(&mut self.repeating_scope, scope)
}
/// Try to resolve the type for the given node, returning t_err if an error results. Note that
@ -269,9 +277,11 @@ impl<'a, 'tcx> Rcx<'a, 'tcx> {
fn visit_fn_body(&mut self,
id: ast::NodeId,
fn_decl: &ast::FnDecl,
body: &ast::Block)
body: &ast::Block,
span: Span)
{
// When we enter a function, we can derive
debug!("visit_fn_body(id={})", id);
let fn_sig_map = self.fcx.inh.fn_sig_map.borrow();
let fn_sig = match fn_sig_map.get(&id) {
@ -283,17 +293,24 @@ impl<'a, 'tcx> Rcx<'a, 'tcx> {
};
let len = self.region_bound_pairs.len();
self.relate_free_regions(&fn_sig[], body.id);
let old_body_id = self.set_body_id(body.id);
self.relate_free_regions(&fn_sig[], body.id, span);
link_fn_args(self, CodeExtent::from_node_id(body.id), &fn_decl.inputs[]);
self.visit_block(body);
self.visit_region_obligations(body.id);
self.region_bound_pairs.truncate(len);
self.set_body_id(old_body_id);
}
fn visit_region_obligations(&mut self, node_id: ast::NodeId)
{
debug!("visit_region_obligations: node_id={}", node_id);
// region checking can introduce new pending obligations
// which, when processed, might generate new region
// obligations. So make sure we process those.
vtable::select_all_fcx_obligations_or_error(self.fcx);
// Make a copy of the region obligations vec because we'll need
// to be able to borrow the fulfillment-cx below when projecting.
let region_obligations =
@ -326,7 +343,8 @@ impl<'a, 'tcx> Rcx<'a, 'tcx> {
/// Tests: `src/test/compile-fail/regions-free-region-ordering-*.rs`
fn relate_free_regions(&mut self,
fn_sig_tys: &[Ty<'tcx>],
body_id: ast::NodeId) {
body_id: ast::NodeId,
span: Span) {
debug!("relate_free_regions >>");
let tcx = self.tcx();
@ -335,25 +353,22 @@ impl<'a, 'tcx> Rcx<'a, 'tcx> {
debug!("relate_free_regions(t={})", ty.repr(tcx));
let body_scope = CodeExtent::from_node_id(body_id);
let body_scope = ty::ReScope(body_scope);
let constraints =
regionmanip::region_wf_constraints(
tcx,
ty,
body_scope);
for constraint in &constraints {
debug!("constraint: {}", constraint.repr(tcx));
match *constraint {
regionmanip::RegionSubRegionConstraint(_,
ty::ReFree(free_a),
ty::ReFree(free_b)) => {
let implications = implicator::implications(self.fcx.infcx(), self.fcx, body_id,
ty, body_scope, span);
for implication in implications {
debug!("implication: {}", implication.repr(tcx));
match implication {
implicator::Implication::RegionSubRegion(_,
ty::ReFree(free_a),
ty::ReFree(free_b)) => {
tcx.region_maps.relate_free_regions(free_a, free_b);
}
regionmanip::RegionSubRegionConstraint(_,
ty::ReFree(free_a),
ty::ReInfer(ty::ReVar(vid_b))) => {
implicator::Implication::RegionSubRegion(_,
ty::ReFree(free_a),
ty::ReInfer(ty::ReVar(vid_b))) => {
self.fcx.inh.infcx.add_given(free_a, vid_b);
}
regionmanip::RegionSubRegionConstraint(..) => {
implicator::Implication::RegionSubRegion(..) => {
// In principle, we could record (and take
// advantage of) every relationship here, but
// we are also free not to -- it simply means
@ -364,12 +379,13 @@ impl<'a, 'tcx> Rcx<'a, 'tcx> {
// relationship that arises here, but
// presently we do not.)
}
regionmanip::RegionSubGenericConstraint(_, r_a, ref generic_b) => {
debug!("RegionSubGenericConstraint: {} <= {}",
implicator::Implication::RegionSubGeneric(_, r_a, ref generic_b) => {
debug!("RegionSubGeneric: {} <= {}",
r_a.repr(tcx), generic_b.repr(tcx));
self.region_bound_pairs.push((r_a, generic_b.clone()));
}
implicator::Implication::Predicate(..) => { }
}
}
}
@ -400,8 +416,8 @@ impl<'a, 'tcx, 'v> Visitor<'v> for Rcx<'a, 'tcx> {
// regions, until regionck, as described in #3238.
fn visit_fn(&mut self, _fk: visit::FnKind<'v>, fd: &'v ast::FnDecl,
b: &'v ast::Block, _s: Span, id: ast::NodeId) {
self.visit_fn_body(id, fd, b)
b: &'v ast::Block, span: Span, id: ast::NodeId) {
self.visit_fn_body(id, fd, b, span)
}
fn visit_item(&mut self, i: &ast::Item) { visit_item(self, i); }
@ -628,7 +644,7 @@ fn visit_expr(rcx: &mut Rcx, expr: &ast::Expr) {
constrain_call(rcx, expr, Some(&**base),
None::<ast::Expr>.iter(), true);
let fn_ret = // late-bound regions in overloaded method calls are instantiated
ty::assert_no_late_bound_regions(rcx.tcx(), &ty::ty_fn_ret(method.ty));
ty::no_late_bound_regions(rcx.tcx(), &ty::ty_fn_ret(method.ty)).unwrap();
fn_ret.unwrap()
}
None => rcx.resolve_node_type(base.id)
@ -975,7 +991,7 @@ fn constrain_autoderefs<'a, 'tcx>(rcx: &mut Rcx<'a, 'tcx>,
// was applied on the base type, as that is always the case.
let fn_sig = ty::ty_fn_sig(method.ty);
let fn_sig = // late-bound regions should have been instantiated
ty::assert_no_late_bound_regions(rcx.tcx(), fn_sig);
ty::no_late_bound_regions(rcx.tcx(), fn_sig).unwrap();
let self_ty = fn_sig.inputs[0];
let (m, r) = match self_ty.sty {
ty::ty_rptr(r, ref m) => (m.mutbl, r),
@ -1481,28 +1497,32 @@ pub fn type_must_outlive<'a, 'tcx>(rcx: &mut Rcx<'a, 'tcx>,
ty.repr(rcx.tcx()),
region.repr(rcx.tcx()));
let constraints =
regionmanip::region_wf_constraints(
rcx.tcx(),
ty,
region);
for constraint in &constraints {
debug!("constraint: {}", constraint.repr(rcx.tcx()));
match *constraint {
regionmanip::RegionSubRegionConstraint(None, r_a, r_b) => {
let implications = implicator::implications(rcx.fcx.infcx(), rcx.fcx, rcx.body_id,
ty, region, origin.span());
for implication in implications {
debug!("implication: {}", implication.repr(rcx.tcx()));
match implication {
implicator::Implication::RegionSubRegion(None, r_a, r_b) => {
rcx.fcx.mk_subr(origin.clone(), r_a, r_b);
}
regionmanip::RegionSubRegionConstraint(Some(ty), r_a, r_b) => {
implicator::Implication::RegionSubRegion(Some(ty), r_a, r_b) => {
let o1 = infer::ReferenceOutlivesReferent(ty, origin.span());
rcx.fcx.mk_subr(o1, r_a, r_b);
}
regionmanip::RegionSubGenericConstraint(None, r_a, ref generic_b) => {
implicator::Implication::RegionSubGeneric(None, r_a, ref generic_b) => {
generic_must_outlive(rcx, origin.clone(), r_a, generic_b);
}
regionmanip::RegionSubGenericConstraint(Some(ty), r_a, ref generic_b) => {
implicator::Implication::RegionSubGeneric(Some(ty), r_a, ref generic_b) => {
let o1 = infer::ReferenceOutlivesReferent(ty, origin.span());
generic_must_outlive(rcx, o1, r_a, generic_b);
}
implicator::Implication::Predicate(def_id, predicate) => {
let cause = traits::ObligationCause::new(origin.span(),
rcx.body_id,
traits::ItemObligation(def_id));
let obligation = traits::Obligation::new(cause, predicate);
rcx.fcx.register_predicate(obligation);
}
}
}
}

12
src/librustc_typeck/check/wf.rs
View File

@ -97,14 +97,10 @@ impl<'ccx, 'tcx> CheckTypeWellFormedVisitor<'ccx, 'tcx> {
self.check_item_type(item);
}
ast::ItemStruct(ref struct_def, _) => {
self.check_type_defn(item, |fcx| {
vec![struct_variant(fcx, &**struct_def)]
});
self.check_type_defn(item, |fcx| vec![struct_variant(fcx, &**struct_def)]);
}
ast::ItemEnum(ref enum_def, _) => {
self.check_type_defn(item, |fcx| {
enum_variants(fcx, enum_def)
});
self.check_type_defn(item, |fcx| enum_variants(fcx, enum_def));
}
ast::ItemTrait(..) => {
let trait_predicates =
@ -578,8 +574,8 @@ fn enum_variants<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
// the regions in the argument types come from the
// enum def'n, and hence will all be early bound
let arg_tys =
ty::assert_no_late_bound_regions(
fcx.tcx(), &ty::ty_fn_args(ctor_ty));
ty::no_late_bound_regions(
fcx.tcx(), &ty::ty_fn_args(ctor_ty)).unwrap();
AdtVariant {
fields: args.iter().enumerate().map(|(index, arg)| {
let arg_ty = arg_tys[index];

59
src/test/compile-fail/regions-assoc-type-in-supertrait-outlives-container.rs Normal file
View File

@ -0,0 +1,59 @@
// 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 we are imposing the requirement that every associated
// type of a bound that appears in the where clause on a struct must
// outlive the location in which the type appears, even when the
// associted type is in a supertype. Issue #22246.
#![allow(dead_code)]
use std::mem::transmute;
use std::ops::Deref;
///////////////////////////////////////////////////////////////////////////
pub trait TheTrait {
type TheAssocType;
fn dummy(&self) { }
}
pub trait TheSubTrait : TheTrait {
}
pub struct TheType<'b> {
m: [fn(&'b()); 0]
}
impl<'b> TheTrait for TheType<'b> {
type TheAssocType = &'b ();
}
impl<'b> TheSubTrait for TheType<'b> {
}
///////////////////////////////////////////////////////////////////////////
pub struct WithAssoc<T:TheSubTrait> {
m: [T; 0]
}
fn with_assoc<'a,'b>() {
// For this type to be valid, the rules require that all
// associated types of traits that appear in `WithAssoc` must
// outlive 'a. In this case, that means TheType<'b>::TheAssocType,
// which is &'b (), must outlive 'a.
let _: &'a WithAssoc<TheType<'b>> = loop { }; //~ ERROR cannot infer
}
fn main() {
}

70
src/test/compile-fail/regions-assoc-type-outlives-container-hrtb.rs Normal file
View File

@ -0,0 +1,70 @@
// 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 structs with higher-ranked where clauses don't generate
// "outlives" requirements. Issue #22246.
#![allow(dead_code)]
#![feature(rustc_attrs)]
///////////////////////////////////////////////////////////////////////////
pub trait TheTrait<'b> {
type TheAssocType;
fn dummy(&'b self) { }
}
pub struct TheType<'b> {
m: [fn(&'b()); 0]
}
impl<'a,'b> TheTrait<'a> for TheType<'b> {
type TheAssocType = &'b ();
}
///////////////////////////////////////////////////////////////////////////
pub struct WithHrAssoc<T>
where for<'a> T : TheTrait<'a>
{
m: [T; 0]
}
fn with_assoc<'a,'b>() {
// We get no error here because the where clause has a higher-ranked assoc type,
// which could not be projected from.
let _: &'a WithHrAssoc<TheType<'b>> = loop { };
}
///////////////////////////////////////////////////////////////////////////
pub trait TheSubTrait : for<'a> TheTrait<'a> {
}
impl<'b> TheSubTrait for TheType<'b> { }
pub struct WithHrAssocSub<T>
where T : TheSubTrait
{
m: [T; 0]
}
fn with_assoc_sub<'a,'b>() {
// Same here, because although the where clause is not HR, it
// extends a trait in a HR way.
let _: &'a WithHrAssocSub<TheType<'b>> = loop { };
}
#[rustc_error]
fn main() { //~ ERROR compilation successful
}

53
src/test/compile-fail/regions-assoc-type-outlives-container-wc.rs Normal file
View File

@ -0,0 +1,53 @@
// 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 we are imposing the requirement that every associated
// type of a bound that appears in the where clause on a struct must
// outlive the location in which the type appears, even when the
// constraint is in a where clause not a bound. Issue #22246.
#![allow(dead_code)]
use std::mem::transmute;
use std::ops::Deref;
///////////////////////////////////////////////////////////////////////////
pub trait TheTrait {
type TheAssocType;
fn dummy(&self) { }
}
pub struct TheType<'b> {
m: [fn(&'b()); 0]
}
impl<'b> TheTrait for TheType<'b> {
type TheAssocType = &'b ();
}
///////////////////////////////////////////////////////////////////////////
pub struct WithAssoc<T> where T : TheTrait {
m: [T; 0]
}
fn with_assoc<'a,'b>() {
// For this type to be valid, the rules require that all
// associated types of traits that appear in `WithAssoc` must
// outlive 'a. In this case, that means TheType<'b>::TheAssocType,
// which is &'b (), must outlive 'a.
let _: &'a WithAssoc<TheType<'b>> = loop { }; //~ ERROR cannot infer
}
fn main() {
}

91
src/test/compile-fail/regions-assoc-type-outlives-container.rs Normal file
View File

@ -0,0 +1,91 @@
// 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 we are imposing the requirement that every associated
// type of a bound that appears in the where clause on a struct must
// outlive the location in which the type appears. Issue #22246.
#![allow(dead_code)]
use std::mem::transmute;
use std::ops::Deref;
///////////////////////////////////////////////////////////////////////////
pub trait TheTrait {
type TheAssocType;
fn dummy(&self) { }
}
pub struct TheType<'b> {
m: [fn(&'b()); 0]
}
impl<'b> TheTrait for TheType<'b> {
type TheAssocType = &'b ();
}
///////////////////////////////////////////////////////////////////////////
pub struct WithAssoc<T:TheTrait> {
m: [T; 0]
}
pub struct WithoutAssoc<T> {
m: [T; 0]
}
fn with_assoc<'a,'b>() {
// For this type to be valid, the rules require that all
// associated types of traits that appear in `WithAssoc` must
// outlive 'a. In this case, that means TheType<'b>::TheAssocType,
// which is &'b (), must outlive 'a.
let _: &'a WithAssoc<TheType<'b>> = loop { }; //~ ERROR cannot infer
}
fn with_assoc1<'a,'b>() where 'b : 'a {
// For this type to be valid, the rules require that all
// associated types of traits that appear in `WithAssoc` must
// outlive 'a. In this case, that means TheType<'b>::TheAssocType,
// which is &'b (), must outlive 'a, so 'b : 'a must hold, and
// that is in the where clauses, so we're fine.
let _: &'a WithAssoc<TheType<'b>> = loop { };
}
fn without_assoc<'a,'b>() {
// Here there are no associated types and the `'b` appearing in
// `TheType<'b>` is purely covariant, so there is no requirement
// that `'b:'a` holds.
let _: &'a WithoutAssoc<TheType<'b>> = loop { };
}
fn call_with_assoc<'a,'b>() {
// As `with_assoc`, but just checking that we impose the same rule
// on the value supplied for the type argument, even when there is
// no data.
call::<&'a WithAssoc<TheType<'b>>>();
//~^ ERROR cannot infer
}
fn call_without_assoc<'a,'b>() {
// As `without_assoc`, but in a distinct scenario.
call::<&'a WithoutAssoc<TheType<'b>>>();
}
fn call<T>() { }
fn main() {
}

35
src/test/run-pass/regions-issue-22246.rs Normal file
View File

@ -0,0 +1,35 @@
// 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.
// Regression test for issue #22246 -- we should be able to deduce
// that `&'a B::Owned` implies that `B::Owned : 'a`.
#![allow(dead_code)]
use std::ops::Deref;
pub trait ToOwned {
type Owned: Borrow<Self>;
fn to_owned(&self) -> Self::Owned;
}
pub trait Borrow<Borrowed> {
fn borrow(&self) -> &Borrowed;
}
pub struct Foo<B:ToOwned> {
owned: B::Owned
}
fn foo<B:ToOwned>(this: &Foo<B>) -> &B {
this.owned.borrow()
}
fn main() { }

34
src/test/run-pass/traits-issue-22110.rs Normal file
View File

@ -0,0 +1,34 @@
// 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 an issue where we reported ambiguity between the where-clause
// and the blanket impl. The only important thing is that compilation
// succeeds here. Issue #22110.
#![allow(dead_code)]
trait Foo<A> {
fn foo(&self, a: A);
}
impl<A,F:Fn(A)> Foo<A> for F {
fn foo(&self, _: A) { }
}
fn baz<A,F:for<'a> Foo<(&'a A,)>>(_: F) { }
fn components<T,A>(t: fn(&A))
where fn(&A) : for<'a> Foo<(&'a A,)>,
{
baz(t)
}
fn main() {
}