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Cleanup some remains of hr_lifetime_in_assoc_type compatibility lint #43543

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merged 1 commit into from
Jul 30, 2017
Merged

Cleanup some remains of hr_lifetime_in_assoc_type compatibility lint #43543

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1 change: 0 additions & 1 deletion src/librustc/ich/impls_ty.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -368,7 +368,6 @@ for ty::RegionParameterDef {
name,
def_id,
index,
issue_32330: _,
pure_wrt_drop
} = *self;

Expand Down
35 changes: 2 additions & 33 deletions src/librustc/infer/error_reporting/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -66,8 +66,7 @@ use hir::map as hir_map;
use hir::def_id::DefId;
use middle::region;
use traits::{ObligationCause, ObligationCauseCode};
use ty::{self, TyCtxt, TypeFoldable};
use ty::{Region, Issue32330};
use ty::{self, Region, TyCtxt, TypeFoldable};
use ty::error::TypeError;
use syntax::ast::DUMMY_NODE_ID;
use syntax_pos::{Pos, Span};
Expand Down Expand Up @@ -713,35 +712,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
self.tcx.note_and_explain_type_err(diag, terr, span);
}

pub fn note_issue_32330(&self,
diag: &mut DiagnosticBuilder<'tcx>,
terr: &TypeError<'tcx>)
{
debug!("note_issue_32330: terr={:?}", terr);
match *terr {
TypeError::RegionsInsufficientlyPolymorphic(_, _, Some(box Issue32330 {
fn_def_id, region_name
})) |
TypeError::RegionsOverlyPolymorphic(_, _, Some(box Issue32330 {
fn_def_id, region_name
})) => {
diag.note(
&format!("lifetime parameter `{0}` declared on fn `{1}` \
appears only in the return type, \
but here is required to be higher-ranked, \
which means that `{0}` must appear in both \
argument and return types",
region_name,
self.tcx.item_path_str(fn_def_id)));
diag.note(
&format!("this error is the result of a recent bug fix; \
for more information, see issue #33685 \
<https://github.com/rust-lang/rust/issues/33685>"));
}
_ => {}
}
}

pub fn report_and_explain_type_error(&self,
trace: TypeTrace<'tcx>,
terr: &TypeError<'tcx>)
Expand All @@ -761,7 +731,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
}
};
self.note_type_err(&mut diag, &trace.cause, None, Some(trace.values), terr);
self.note_issue_32330(&mut diag, terr);
diag
}

Expand Down Expand Up @@ -934,7 +903,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
format!(" for lifetime parameter {}in trait containing associated type `{}`",
br_string(br), type_name)
}
infer::EarlyBoundRegion(_, name, _) => {
infer::EarlyBoundRegion(_, name) => {
format!(" for lifetime parameter `{}`",
name)
}
Expand Down
56 changes: 7 additions & 49 deletions src/librustc/infer/higher_ranked/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,9 +13,7 @@

use super::{CombinedSnapshot,
InferCtxt,
LateBoundRegion,
HigherRankedType,
RegionVariableOrigin,
SubregionOrigin,
SkolemizationMap};
use super::combine::CombineFields;
Expand All @@ -29,15 +27,6 @@ use util::nodemap::{FxHashMap, FxHashSet};

pub struct HrMatchResult<U> {
pub value: U,

/// Normally, when we do a higher-ranked match operation, we
/// expect all higher-ranked regions to be constrained as part of
/// the match operation. However, in the transition period for
/// #32330, it can happen that we sometimes have unconstrained
/// regions that get instantiated with fresh variables. In that
/// case, we collect the set of unconstrained bound regions here
/// and replace them with fresh variables.
pub unconstrained_regions: Vec<ty::BoundRegion>,
}

impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
Expand Down Expand Up @@ -108,7 +97,6 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
/// that do not appear in `T`. If that happens, those regions are
/// unconstrained, and this routine replaces them with `'static`.
pub fn higher_ranked_match<T, U>(&mut self,
span: Span,
a_pair: &Binder<(T, U)>,
b_match: &T,
a_is_expected: bool)
Expand Down Expand Up @@ -158,28 +146,16 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
// be any region from the sets above, except for other members of
// `skol_map`. There should always be a representative if things
// are properly well-formed.
let mut unconstrained_regions = vec![];
let skol_representatives: FxHashMap<_, _> =
skol_resolution_map
.iter()
.map(|(&skol, &(br, ref regions))| {
.map(|(&skol, &(_, ref regions))| {
let representative =
regions.iter()
.filter(|&&r| !skol_resolution_map.contains_key(r))
.cloned()
.next()
.unwrap_or_else(|| { // [1]
unconstrained_regions.push(br);
self.infcx.next_region_var(
LateBoundRegion(span, br, HigherRankedType))
});

// [1] There should always be a representative,
// unless the higher-ranked region did not appear
// in the values being matched. We should reject
// as ill-formed cases that can lead to this, but
// right now we sometimes issue warnings (see
// #32330).
.expect("no representative region");

(skol, representative)
})
Expand Down Expand Up @@ -216,10 +192,7 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
// We are now done with these skolemized variables.
self.infcx.pop_skolemized(skol_map, snapshot);

Ok(HrMatchResult {
value: a_value,
unconstrained_regions,
})
Ok(HrMatchResult { value: a_value })
});
}

Expand Down Expand Up @@ -657,28 +630,13 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
skol_br,
tainted_region);

let issue_32330 = if let &ty::ReVar(vid) = tainted_region {
match self.region_vars.var_origin(vid) {
RegionVariableOrigin::EarlyBoundRegion(_, _, issue_32330) => {
issue_32330.map(Box::new)
}
_ => None
}
} else {
None
};

if overly_polymorphic {
return Err(if overly_polymorphic {
debug!("Overly polymorphic!");
return Err(TypeError::RegionsOverlyPolymorphic(skol_br,
tainted_region,
issue_32330));
TypeError::RegionsOverlyPolymorphic(skol_br, tainted_region)
} else {
debug!("Not as polymorphic!");
return Err(TypeError::RegionsInsufficientlyPolymorphic(skol_br,
tainted_region,
issue_32330));
}
TypeError::RegionsInsufficientlyPolymorphic(skol_br, tainted_region)
})
}
}

Expand Down
7 changes: 3 additions & 4 deletions src/librustc/infer/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -299,7 +299,7 @@ pub enum RegionVariableOrigin {
Coercion(Span),

// Region variables created as the values for early-bound regions
EarlyBoundRegion(Span, ast::Name, Option<ty::Issue32330>),
EarlyBoundRegion(Span, ast::Name),

// Region variables created for bound regions
// in a function or method that is called
Expand Down Expand Up @@ -989,7 +989,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
span: Span,
def: &ty::RegionParameterDef)
-> ty::Region<'tcx> {
self.next_region_var(EarlyBoundRegion(span, def.name, def.issue_32330))
self.next_region_var(EarlyBoundRegion(span, def.name))
}

/// Create a type inference variable for the given
Expand Down Expand Up @@ -1278,14 +1278,13 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
-> InferResult<'tcx, HrMatchResult<Ty<'tcx>>>
{
let match_pair = match_a.map_bound(|p| (p.projection_ty.trait_ref(self.tcx), p.ty));
let span = cause.span;
let trace = TypeTrace {
cause,
values: TraitRefs(ExpectedFound::new(true, match_pair.skip_binder().0, match_b))
};

let mut combine = self.combine_fields(trace, param_env);
let result = combine.higher_ranked_match(span, &match_pair, &match_b, true)?;
let result = combine.higher_ranked_match(&match_pair, &match_b, true)?;
Ok(InferOk { value: result, obligations: combine.obligations })
}

Expand Down
38 changes: 6 additions & 32 deletions src/librustc/middle/resolve_lifetime.rs
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Expand Up @@ -153,10 +153,6 @@ pub struct NamedRegionMap {
// (b) it DOES appear in the arguments.
pub late_bound: NodeSet,

// Contains the node-ids for lifetimes that were (incorrectly) categorized
// as late-bound, until #32330 was fixed.
pub issue_32330: NodeMap<ty::Issue32330>,

// For each type and trait definition, maps type parameters
// to the trait object lifetime defaults computed from them.
pub object_lifetime_defaults: NodeMap<Vec<ObjectLifetimeDefault>>,
Expand Down Expand Up @@ -261,7 +257,6 @@ pub fn krate(sess: &Session,
let mut map = NamedRegionMap {
defs: NodeMap(),
late_bound: NodeSet(),
issue_32330: NodeMap(),
object_lifetime_defaults: compute_object_lifetime_defaults(sess, hir_map),
};
sess.track_errors(|| {
Expand Down Expand Up @@ -303,7 +298,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
fn visit_item(&mut self, item: &'tcx hir::Item) {
match item.node {
hir::ItemFn(ref decl, _, _, _, ref generics, _) => {
self.visit_early_late(item.id, None, decl, generics, |this| {
self.visit_early_late(None, decl, generics, |this| {
intravisit::walk_item(this, item);
});
}
Expand Down Expand Up @@ -355,7 +350,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
fn visit_foreign_item(&mut self, item: &'tcx hir::ForeignItem) {
match item.node {
hir::ForeignItemFn(ref decl, _, ref generics) => {
self.visit_early_late(item.id, None, decl, generics, |this| {
self.visit_early_late(None, decl, generics, |this| {
intravisit::walk_foreign_item(this, item);
})
}
Expand Down Expand Up @@ -406,7 +401,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
if let hir::TraitItemKind::Method(ref sig, _) = trait_item.node {
self.visit_early_late(
trait_item.id,
Some(self.hir_map.get_parent(trait_item.id)),
&sig.decl, &sig.generics,
|this| intravisit::walk_trait_item(this, trait_item))
Expand All @@ -418,7 +412,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
if let hir::ImplItemKind::Method(ref sig, _) = impl_item.node {
self.visit_early_late(
impl_item.id,
Some(self.hir_map.get_parent(impl_item.id)),
&sig.decl, &sig.generics,
|this| intravisit::walk_impl_item(this, impl_item))
Expand Down Expand Up @@ -811,18 +804,13 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
/// bound lifetimes are resolved by name and associated with a binder id (`binder_id`), so the
/// ordering is not important there.
fn visit_early_late<F>(&mut self,
fn_id: ast::NodeId,
parent_id: Option<ast::NodeId>,
decl: &'tcx hir::FnDecl,
generics: &'tcx hir::Generics,
walk: F) where
F: for<'b, 'c> FnOnce(&'b mut LifetimeContext<'c, 'tcx>),
{
let fn_def_id = self.hir_map.local_def_id(fn_id);
insert_late_bound_lifetimes(self.map,
fn_def_id,
decl,
generics);
insert_late_bound_lifetimes(self.map, decl, generics);

// Find the start of nested early scopes, e.g. in methods.
let mut index = 0;
Expand Down Expand Up @@ -1549,7 +1537,6 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
/// not amongst the inputs to a projection. In other words, `<&'a
/// T as Trait<''b>>::Foo` does not constrain `'a` or `'b`.
fn insert_late_bound_lifetimes(map: &mut NamedRegionMap,
fn_def_id: DefId,
decl: &hir::FnDecl,
generics: &hir::Generics) {
debug!("insert_late_bound_lifetimes(decl={:?}, generics={:?})", decl, generics);
Expand Down Expand Up @@ -1607,22 +1594,9 @@ fn insert_late_bound_lifetimes(map: &mut NamedRegionMap,
// any `impl Trait` in the return type? early-bound.
if appears_in_output.impl_trait { continue; }

// does not appear in the inputs, but appears in the return
// type? eventually this will be early-bound, but for now we
// just mark it so we can issue warnings.
let constrained_by_input = constrained_by_input.regions.contains(&name);
let appears_in_output = appears_in_output.regions.contains(&name);
if !constrained_by_input && appears_in_output {
debug!("inserting issue_32330 entry for {:?}, {:?} on {:?}",
lifetime.lifetime.id,
name,
fn_def_id);
map.issue_32330.insert(
lifetime.lifetime.id,
ty::Issue32330 {
fn_def_id,
region_name: name,
});
// does not appear in the inputs, but appears in the return type? early-bound.
if !constrained_by_input.regions.contains(&name) &&
appears_in_output.regions.contains(&name) {
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Nit: I prefer the temporary variables; seems easier to read to me, particularly since the body here is indented the same as the condition (in which case I would typically move the { to the next line). But .. whatever. =)

continue;
}

Expand Down
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