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rollup merge of #18868: nikomatsakis/issue-17388-unbound-path-assoc-type 

This fixes #17388.

Note that we don't check type parameters in trait-references and so on, so we accept some nonsense (I opened https://github.com/rust-lang/rust/issues/18865). (It may be easier to just add support for `T::Foo` and deprecate the qpath code until we can implement it more robustly using the trait lookup infrastructure, not sure.)
This commit is contained in:
Jakub Bukaj 2014-11-19 22:37:02 +01:00
parent fee71bd476 b64c7b83dd
commit 655eb44df3
16 changed files with 119 additions and 187 deletions
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63
src/librustc/middle/resolve.rs
View File

@ -633,6 +633,7 @@ enum TraitReferenceType {
TraitDerivation, // trait T : SomeTrait { ... }
TraitBoundingTypeParameter, // fn f<T:SomeTrait>() { ... }
TraitObject, // Box<for<'a> SomeTrait>
TraitQPath, // <T as SomeTrait>::
}
impl NameBindings {
@ -4532,6 +4533,7 @@ impl<'a> Resolver<'a> {
TraitImplementation => "implement",
TraitDerivation => "derive",
TraitObject => "reference",
TraitQPath => "extract an associated type from",
};
let msg = format!("attempt to {} a nonexistent trait `{}`", usage_str, path_str);
@ -4969,65 +4971,8 @@ impl<'a> Resolver<'a> {
}
TyQPath(ref qpath) => {
self.resolve_type(&*qpath.for_type);
let current_module = self.current_module.clone();
let module_path: Vec<_> =
qpath.trait_name
.segments
.iter()
.map(|ps| ps.identifier.name)
.collect();
match self.resolve_module_path(
current_module,
module_path.as_slice(),
UseLexicalScope,
qpath.trait_name.span,
PathSearch) {
Success((ref module, _)) if module.kind.get() ==
TraitModuleKind => {
match self.resolve_definition_of_name_in_module(
(*module).clone(),
qpath.item_name.name,
TypeNS) {
ChildNameDefinition(def, lp) |
ImportNameDefinition(def, lp) => {
match def {
DefAssociatedTy(trait_type_id) => {
let def = DefAssociatedTy(
trait_type_id);
self.record_def(ty.id, (def, lp));
}
_ => {
self.resolve_error(
ty.span,
"not an associated type");
}
}
}
NoNameDefinition => {
self.resolve_error(ty.span,
"unresolved associated \
type");
}
}
}
Success(..) => self.resolve_error(ty.span, "not a trait"),
Indeterminate => {
self.session.span_bug(ty.span,
"indeterminate result when \
resolving associated type")
}
Failed(error) => {
let (span, help) = match error {
Some((span, msg)) => (span, format!("; {}", msg)),
None => (ty.span, String::new()),
};
self.resolve_error(span,
format!("unresolved trait: {}",
help).as_slice())
}
}
self.resolve_type(&*qpath.self_type);
self.resolve_trait_reference(ty.id, &*qpath.trait_ref, TraitQPath);
}
TyClosure(ref c) | TyProc(ref c) => {

4
src/librustc/middle/subst.rs
View File

@ -100,6 +100,10 @@ impl<'tcx> Substs<'tcx> {
regions_is_noop && self.types.is_empty()
}
pub fn type_for_def(&self, ty_param_def: &ty::TypeParameterDef) -> Ty<'tcx> {
*self.types.get(ty_param_def.space, ty_param_def.index)
}
pub fn has_regions_escaping_depth(&self, depth: uint) -> bool {
self.types.iter().any(|&t| ty::type_escapes_depth(t, depth)) || {
match self.regions {

5
src/librustc/middle/traits/mod.rs
View File

@ -25,6 +25,7 @@ use std::rc::Rc;
use std::slice::Items;
use syntax::ast;
use syntax::codemap::{Span, DUMMY_SP};
use util::common::ErrorReported;
pub use self::fulfill::FulfillmentContext;
pub use self::select::SelectionContext;
@ -95,10 +96,6 @@ pub enum ObligationCauseCode<'tcx> {
FieldSized,
}
// An error has already been reported to the user, so no need to continue checking.
#[deriving(Clone,Show)]
pub struct ErrorReported;
pub type Obligations<'tcx> = subst::VecPerParamSpace<Obligation<'tcx>>;
pub type Selection<'tcx> = Vtable<'tcx, Obligation<'tcx>>;

2
src/librustc/middle/traits/select.rs
View File

@ -17,7 +17,6 @@ use self::Candidate::*;
use self::BuiltinBoundConditions::*;
use self::EvaluationResult::*;
use super::{ErrorReported};
use super::{Obligation, ObligationCause};
use super::{SelectionError, Unimplemented, Overflow,
OutputTypeParameterMismatch};
@ -38,6 +37,7 @@ use std::cell::RefCell;
use std::collections::hash_map::HashMap;
use std::rc::Rc;
use syntax::ast;
use util::common::ErrorReported;
use util::ppaux::Repr;
pub struct SelectionContext<'cx, 'tcx:'cx> {

3
src/librustc/middle/traits/util.rs
View File

@ -18,9 +18,10 @@ use std::fmt;
use std::rc::Rc;
use syntax::ast;
use syntax::codemap::Span;
use util::common::ErrorReported;
use util::ppaux::Repr;
use super::{ErrorReported, Obligation, ObligationCause, VtableImpl,
use super::{Obligation, ObligationCause, VtableImpl,
VtableParam, VtableParamData, VtableImplData};
///////////////////////////////////////////////////////////////////////////

122
src/librustc/middle/typeck/astconv.rs
View File

@ -207,7 +207,6 @@ fn ast_path_substs_for_ty<'tcx,AC,RS>(
decl_def_id: ast::DefId,
decl_generics: &ty::Generics<'tcx>,
self_ty: Option<Ty<'tcx>>,
associated_ty: Option<Ty<'tcx>>,
path: &ast::Path)
-> Substs<'tcx>
where AC: AstConv<'tcx>, RS: RegionScope
@ -243,7 +242,7 @@ fn ast_path_substs_for_ty<'tcx,AC,RS>(
};
create_substs_for_ast_path(this, rscope, path.span, decl_def_id,
decl_generics, self_ty, types, regions, associated_ty)
decl_generics, self_ty, types, regions)
}
fn create_substs_for_ast_path<'tcx,AC,RS>(
@ -254,8 +253,7 @@ fn create_substs_for_ast_path<'tcx,AC,RS>(
decl_generics: &ty::Generics<'tcx>,
self_ty: Option<Ty<'tcx>>,
types: Vec<Ty<'tcx>>,
regions: Vec<ty::Region>,
associated_ty: Option<Ty<'tcx>>)
regions: Vec<ty::Region>)
-> Substs<'tcx>
where AC: AstConv<'tcx>, RS: RegionScope
{
@ -366,9 +364,9 @@ fn create_substs_for_ast_path<'tcx,AC,RS>(
substs.types.push(
AssocSpace,
this.associated_type_binding(span,
associated_ty,
self_ty,
decl_def_id,
param.def_id))
param.def_id));
}
return substs;
@ -417,19 +415,17 @@ pub fn instantiate_poly_trait_ref<'tcx,AC,RS>(
this: &AC,
rscope: &RS,
ast_trait_ref: &ast::PolyTraitRef,
self_ty: Option<Ty<'tcx>>,
associated_type: Option<Ty<'tcx>>)
self_ty: Option<Ty<'tcx>>)
-> Rc<ty::TraitRef<'tcx>>
where AC: AstConv<'tcx>, RS: RegionScope
{
instantiate_trait_ref(this, rscope, &ast_trait_ref.trait_ref, self_ty, associated_type)
instantiate_trait_ref(this, rscope, &ast_trait_ref.trait_ref, self_ty)
}
pub fn instantiate_trait_ref<'tcx,AC,RS>(this: &AC,
rscope: &RS,
ast_trait_ref: &ast::TraitRef,
self_ty: Option<Ty<'tcx>>,
associated_type: Option<Ty<'tcx>>)
self_ty: Option<Ty<'tcx>>)
-> Rc<ty::TraitRef<'tcx>>
where AC: AstConv<'tcx>,
RS: RegionScope
@ -444,8 +440,8 @@ pub fn instantiate_trait_ref<'tcx,AC,RS>(this: &AC,
ast_trait_ref.path.span,
ast_trait_ref.ref_id) {
def::DefTrait(trait_def_id) => {
let trait_ref = Rc::new(ast_path_to_trait_ref(this, rscope, trait_def_id, self_ty,
associated_type, &ast_trait_ref.path));
let trait_ref = Rc::new(ast_path_to_trait_ref(this, rscope, trait_def_id,
self_ty, &ast_trait_ref.path));
this.tcx().trait_refs.borrow_mut().insert(ast_trait_ref.ref_id,
trait_ref.clone());
trait_ref
@ -463,7 +459,6 @@ fn ast_path_to_trait_ref<'tcx,AC,RS>(
rscope: &RS,
trait_def_id: ast::DefId,
self_ty: Option<Ty<'tcx>>,
associated_type: Option<Ty<'tcx>>,
path: &ast::Path)
-> ty::TraitRef<'tcx>
where AC: AstConv<'tcx>, RS: RegionScope
@ -493,8 +488,7 @@ fn ast_path_to_trait_ref<'tcx,AC,RS>(
&trait_def.generics,
self_ty,
types,
regions,
associated_type);
regions);
ty::TraitRef::new(trait_def_id, substs)
}
@ -517,7 +511,6 @@ pub fn ast_path_to_ty<'tcx, AC: AstConv<'tcx>, RS: RegionScope>(
did,
&generics,
None,
None,
path);
let ty = decl_ty.subst(tcx, &substs);
TypeAndSubsts { substs: substs, ty: ty }
@ -558,7 +551,7 @@ pub fn ast_path_to_ty_relaxed<'tcx,AC,RS>(
Substs::new(VecPerParamSpace::params_from_type(type_params),
VecPerParamSpace::params_from_type(region_params))
} else {
ast_path_substs_for_ty(this, rscope, did, &generics, None, None, path)
ast_path_substs_for_ty(this, rscope, did, &generics, None, path)
};
let ty = decl_ty.subst(tcx, &substs);
@ -726,7 +719,6 @@ fn mk_pointer<'tcx, AC: AstConv<'tcx>, RS: RegionScope>(
rscope,
trait_def_id,
None,
None,
path);
let empty_vec = [];
let bounds = match *opt_bounds { None => empty_vec.as_slice(),
@ -750,61 +742,37 @@ fn mk_pointer<'tcx, AC: AstConv<'tcx>, RS: RegionScope>(
constr(ast_ty_to_ty(this, rscope, a_seq_ty))
}
fn associated_ty_to_ty<'tcx,AC,RS>(this: &AC,
rscope: &RS,
trait_path: &ast::Path,
for_ast_type: &ast::Ty,
trait_type_id: ast::DefId,
span: Span)
-> Ty<'tcx>
where AC: AstConv<'tcx>, RS: RegionScope
fn qpath_to_ty<'tcx,AC,RS>(this: &AC,
rscope: &RS,
ast_ty: &ast::Ty, // the TyQPath
qpath: &ast::QPath)
-> Ty<'tcx>
where AC: AstConv<'tcx>, RS: RegionScope
{
debug!("associated_ty_to_ty(trait_path={}, for_ast_type={}, trait_type_id={})",
trait_path.repr(this.tcx()),
for_ast_type.repr(this.tcx()),
trait_type_id.repr(this.tcx()));
debug!("qpath_to_ty(ast_ty={})",
ast_ty.repr(this.tcx()));
// Find the trait that this associated type belongs to.
let trait_did = match ty::impl_or_trait_item(this.tcx(),
trait_type_id).container() {
ty::ImplContainer(_) => {
this.tcx().sess.span_bug(span,
"associated_ty_to_ty(): impl associated \
types shouldn't go through this \
function")
}
ty::TraitContainer(trait_id) => trait_id,
};
let self_type = ast_ty_to_ty(this, rscope, &*qpath.self_type);
let for_type = ast_ty_to_ty(this, rscope, for_ast_type);
if !this.associated_types_of_trait_are_valid(for_type, trait_did) {
this.tcx().sess.span_err(span,
"this associated type is not \
allowed in this context");
return ty::mk_err()
}
debug!("qpath_to_ty: self_type={}", self_type.repr(this.tcx()));
let trait_ref = ast_path_to_trait_ref(this,
let trait_ref = instantiate_trait_ref(this,
rscope,
trait_did,
None,
Some(for_type),
trait_path);
&*qpath.trait_ref,
Some(self_type));
debug!("associated_ty_to_ty(trait_ref={})",
trait_ref.repr(this.tcx()));
debug!("qpath_to_ty: trait_ref={}", trait_ref.repr(this.tcx()));
let trait_def = this.get_trait_def(trait_did);
for type_parameter in trait_def.generics.types.iter() {
if type_parameter.def_id == trait_type_id {
debug!("associated_ty_to_ty(type_parameter={} substs={})",
type_parameter.repr(this.tcx()),
trait_ref.substs.repr(this.tcx()));
return *trait_ref.substs.types.get(type_parameter.space,
type_parameter.index)
let trait_def = this.get_trait_def(trait_ref.def_id);
for ty_param_def in trait_def.generics.types.get_slice(AssocSpace).iter() {
if ty_param_def.name == qpath.item_name.name {
debug!("qpath_to_ty: corresponding ty_param_def={}", ty_param_def);
return trait_ref.substs.type_for_def(ty_param_def);
}
}
this.tcx().sess.span_bug(span,
this.tcx().sess.span_bug(ast_ty.span,
"this associated type didn't get added \
as a parameter for some reason")
}
@ -931,7 +899,6 @@ pub fn ast_ty_to_ty<'tcx, AC: AstConv<'tcx>, RS: RegionScope>(
rscope,
trait_def_id,
None,
None,
path);
let empty_bounds: &[ast::TyParamBound] = &[];
let ast_bounds = match *bounds {
@ -996,26 +963,7 @@ pub fn ast_ty_to_ty<'tcx, AC: AstConv<'tcx>, RS: RegionScope>(
}
}
ast::TyQPath(ref qpath) => {
match tcx.def_map.borrow().get(&ast_ty.id) {
None => {
tcx.sess.span_bug(ast_ty.span,
"unbound qualified path")
}
Some(&def::DefAssociatedTy(trait_type_id)) => {
associated_ty_to_ty(this,
rscope,
&qpath.trait_name,
&*qpath.for_type,
trait_type_id,
ast_ty.span)
}
Some(_) => {
tcx.sess.span_err(ast_ty.span,
"this qualified path does not name \
an associated type");
ty::mk_err()
}
}
qpath_to_ty(this, rscope, ast_ty, &**qpath)
}
ast::TyFixedLengthVec(ref ty, ref e) => {
match const_eval::eval_const_expr_partial(tcx, &**e) {
@ -1411,7 +1359,7 @@ fn conv_ty_poly_trait_ref<'tcx, AC, RS>(
let main_trait_bound = match partitioned_bounds.trait_bounds.remove(0) {
Some(trait_bound) => {
Some(instantiate_poly_trait_ref(this, rscope, trait_bound, None, None))
Some(instantiate_poly_trait_ref(this, rscope, trait_bound, None))
}
None => {
this.tcx().sess.span_err(

31
src/librustc/middle/typeck/collect.rs
View File

@ -684,7 +684,11 @@ fn find_associated_type_in_generics<'tcx>(tcx: &ty::ctxt<'tcx>,
ty: Option<Ty<'tcx>>,
associated_type_id: ast::DefId,
generics: &ty::Generics<'tcx>)
-> Ty<'tcx> {
-> Ty<'tcx>
{
debug!("find_associated_type_in_generics(ty={}, associated_type_id={}, generics={}",
ty.repr(tcx), associated_type_id.repr(tcx), generics.repr(tcx));
let ty = match ty {
None => {
tcx.sess.span_bug(span,
@ -703,20 +707,22 @@ fn find_associated_type_in_generics<'tcx>(tcx: &ty::ctxt<'tcx>,
for type_parameter in generics.types.iter() {
if type_parameter.def_id == associated_type_id
&& type_parameter.associated_with == Some(param_id) {
return ty::mk_param_from_def(tcx, type_parameter)
return ty::mk_param_from_def(tcx, type_parameter);
}
}
tcx.sess.span_bug(span,
"find_associated_type_in_generics(): didn't \
find associated type anywhere in the generics \
list")
tcx.sess.span_err(
span,
format!("no suitable bound on `{}`",
ty.user_string(tcx))[]);
ty::mk_err()
}
_ => {
tcx.sess.span_bug(span,
"find_associated_type_in_generics(): self type \
is not a parameter")
tcx.sess.span_err(
span,
"it is currently unsupported to access associated types except \
through a type parameter; this restriction will be lifted in time");
ty::mk_err()
}
}
}
@ -1155,7 +1161,7 @@ pub fn convert(ccx: &CrateCtxt, it: &ast::Item) {
for trait_ref in opt_trait_ref.iter() {
astconv::instantiate_trait_ref(&icx, &ExplicitRscope, trait_ref,
Some(selfty), None);
Some(selfty));
}
},
ast::ItemTrait(_, _, _, ref trait_methods) => {
@ -1627,7 +1633,7 @@ fn ty_generics_for_trait<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
ccx,
subst::AssocSpace,
&associated_type.ty_param,
generics.types.len(subst::TypeSpace),
generics.types.len(subst::AssocSpace),
&ast_generics.where_clause,
Some(local_def(trait_id)));
ccx.tcx.ty_param_defs.borrow_mut().insert(associated_type.ty_param.id,
@ -2019,7 +2025,6 @@ fn conv_param_bounds<'tcx,AC>(this: &AC,
astconv::instantiate_poly_trait_ref(this,
&ExplicitRscope,
bound,
Some(param_ty.to_ty(this.tcx())),
Some(param_ty.to_ty(this.tcx())))
})
.collect();

4
src/librustc/util/common.rs
View File

@ -20,6 +20,10 @@ use syntax::ast;
use syntax::visit;
use syntax::visit::Visitor;
// An error has already been reported to the user, so no need to continue checking.
#[deriving(Clone,Show)]
pub struct ErrorReported;
pub fn time<T, U>(do_it: bool, what: &str, u: U, f: |U| -> T) -> T {
local_data_key!(depth: uint);
if !do_it { return f(u); }

6
src/libsyntax/ast.rs
View File

@ -706,11 +706,11 @@ pub enum Expr_ {
///
/// <Vec<T> as SomeTrait>::SomeAssociatedItem
/// ^~~~~ ^~~~~~~~~ ^~~~~~~~~~~~~~~~~~
/// for_type trait_name item_name
/// self_type trait_name item_name
#[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash, Show)]
pub struct QPath {
pub for_type: P<Ty>,
pub trait_name: Path,
pub self_type: P<Ty>,
pub trait_ref: P<TraitRef>,
pub item_name: Ident,
}

22
src/libsyntax/fold.rs
View File

@ -142,6 +142,10 @@ pub trait Folder {
noop_fold_ty(t, self)
}
fn fold_qpath(&mut self, t: P<QPath>) -> P<QPath> {
noop_fold_qpath(t, self)
}
fn fold_mod(&mut self, m: Mod) -> Mod {
noop_fold_mod(m, self)
}
@ -435,12 +439,8 @@ pub fn noop_fold_ty<T: Folder>(t: P<Ty>, fld: &mut T) -> P<Ty> {
fld.fold_opt_bounds(bounds),
id)
}
TyQPath(ref qpath) => {
TyQPath(P(QPath {
for_type: fld.fold_ty(qpath.for_type.clone()),
trait_name: fld.fold_path(qpath.trait_name.clone()),
item_name: fld.fold_ident(qpath.item_name.clone()),
}))
TyQPath(qpath) => {
TyQPath(fld.fold_qpath(qpath))
}
TyFixedLengthVec(ty, e) => {
TyFixedLengthVec(fld.fold_ty(ty), fld.fold_expr(e))
@ -456,6 +456,16 @@ pub fn noop_fold_ty<T: Folder>(t: P<Ty>, fld: &mut T) -> P<Ty> {
})
}
pub fn noop_fold_qpath<T: Folder>(qpath: P<QPath>, fld: &mut T) -> P<QPath> {
qpath.map(|qpath| {
QPath {
self_type: fld.fold_ty(qpath.self_type),
trait_ref: qpath.trait_ref.map(|tr| fld.fold_trait_ref(tr)),
item_name: fld.fold_ident(qpath.item_name),
}
})
}
pub fn noop_fold_foreign_mod<T: Folder>(ForeignMod {abi, view_items, items}: ForeignMod,
fld: &mut T) -> ForeignMod {
ForeignMod {

10
src/libsyntax/parse/parser.rs
View File

@ -1502,17 +1502,17 @@ impl<'a> Parser<'a> {
} else if self.eat_keyword(keywords::Proc) {
self.parse_proc_type(Vec::new())
} else if self.token == token::Lt {
// QUALIFIED PATH
// QUALIFIED PATH `<TYPE as TRAIT_REF>::item`
self.bump();
let for_type = self.parse_ty(true);
let self_type = self.parse_ty(true);
self.expect_keyword(keywords::As);
let trait_name = self.parse_path(LifetimeAndTypesWithoutColons);
let trait_ref = self.parse_trait_ref();
self.expect(&token::Gt);
self.expect(&token::ModSep);
let item_name = self.parse_ident();
TyQPath(P(QPath {
for_type: for_type,
trait_name: trait_name.path,
self_type: self_type,
trait_ref: P(trait_ref),
item_name: item_name,
}))
} else if self.token == token::ModSep ||

4
src/libsyntax/print/pprust.rs
View File

@ -744,10 +744,10 @@ impl<'a> State<'a> {
}
ast::TyQPath(ref qpath) => {
try!(word(&mut self.s, "<"));
try!(self.print_type(&*qpath.for_type));
try!(self.print_type(&*qpath.self_type));
try!(space(&mut self.s));
try!(self.word_space("as"));
try!(self.print_path(&qpath.trait_name, false));
try!(self.print_trait_ref(&*qpath.trait_ref));
try!(word(&mut self.s, ">"));
try!(word(&mut self.s, "::"));
try!(self.print_ident(qpath.item_name));

4
src/libsyntax/visit.rs
View File

@ -403,8 +403,8 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty) {
}
}
TyQPath(ref qpath) => {
visitor.visit_ty(&*qpath.for_type);
visitor.visit_path(&qpath.trait_name, typ.id);
visitor.visit_ty(&*qpath.self_type);
visitor.visit_trait_ref(&*qpath.trait_ref);
visitor.visit_ident(typ.span, qpath.item_name);
}
TyFixedLengthVec(ref ty, ref expression) => {

4
src/test/compile-fail/associated-types-in-ambiguous-context.rs
View File

@ -20,12 +20,12 @@ fn get<T:Get,U:Get>(x: T, y: U) -> Get::Value {}
trait Other {
fn uhoh<U:Get>(&self, foo: U, bar: <Self as Get>::Value) {}
//~^ ERROR this associated type is not allowed in this context
//~^ ERROR no suitable bound on `Self`
}
impl<T:Get> Other for T {
fn uhoh<U:Get>(&self, foo: U, bar: <(T, U) as Get>::Value) {}
//~^ ERROR this associated type is not allowed in this context
//~^ ERROR currently unsupported
}
trait Grab {

4
src/test/compile-fail/associated-types-in-wrong-context.rs
View File

@ -16,7 +16,7 @@ trait Get {
}
fn get(x: int) -> <int as Get>::Value {}
//~^ ERROR this associated type is not allowed in this context
//~^ ERROR unsupported
struct Struct {
x: int,
@ -24,7 +24,7 @@ struct Struct {
impl Struct {
fn uhoh<T>(foo: <T as Get>::Value) {}
//~^ ERROR this associated type is not allowed in this context
//~^ ERROR no suitable bound on `T`
}
fn main() {

18
src/test/run-pass/associated-types-qualified-path-with-trait-with-type-parameters.rs Normal file
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// Copyright 2014 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.
#![feature(associated_types)]
trait Foo<T> {
type Bar;
fn get_bar() -> <Self as Foo<T>>::Bar;
}
fn main() { }