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Auto merge of #46706 - sunjay:gat-lifetimes, r=nikomatsakis 

Lifetime Resolution for Generic Associated Types

Tracking Issue: https://github.com/rust-lang/rust/issues/44265

r? @nikomatsakis

This PR implements lifetime resolution for generic associated types. 🎉

## Remaining Work Before Merge

I'm going to go do these things in the next day or so. Please let me know if you spot anything in my changes until then.

- [x] If I'm not mistaken, at least some tests should pass now. I need to go through the tests and re-enable the ones that should work by removing the appropriate `~ ERROR` comments
This commit is contained in:
bors 2017-12-15 10:50:20 +00:00
parent 04b23449c0 f701b4cca0
commit b4f323254a
9 changed files with 156 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

87
src/librustc/middle/resolve_lifetime.rs
View File

@ -646,30 +646,77 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
}
fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
let tcx = self.tcx;
if let hir::TraitItemKind::Method(ref sig, _) = trait_item.node {
self.visit_early_late(
Some(tcx.hir.get_parent(trait_item.id)),
&sig.decl,
&trait_item.generics,
|this| intravisit::walk_trait_item(this, trait_item),
)
} else {
intravisit::walk_trait_item(self, trait_item);
use self::hir::TraitItemKind::*;
match trait_item.node {
Method(ref sig, _) => {
let tcx = self.tcx;
self.visit_early_late(
Some(tcx.hir.get_parent(trait_item.id)),
&sig.decl,
&trait_item.generics,
|this| intravisit::walk_trait_item(this, trait_item),
);
},
Type(ref bounds, ref ty) => {
let generics = &trait_item.generics;
let mut index = self.next_early_index();
debug!("visit_ty: index = {}", index);
let lifetimes = generics.lifetimes.iter()
.map(|lt_def| Region::early(&self.tcx.hir, &mut index, lt_def))
.collect();
let next_early_index = index + generics.ty_params.len() as u32;
let scope = Scope::Binder { lifetimes, next_early_index, s: self.scope };
self.with(scope, |_old_scope, this| {
this.visit_generics(generics);
for bound in bounds {
this.visit_ty_param_bound(bound);
}
if let Some(ty) = ty {
this.visit_ty(ty);
}
});
},
Const(_, _) => {
// Only methods and types support generics.
assert!(!trait_item.generics.is_parameterized());
intravisit::walk_trait_item(self, trait_item);
},
}
}
fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
let tcx = self.tcx;
if let hir::ImplItemKind::Method(ref sig, _) = impl_item.node {
self.visit_early_late(
Some(tcx.hir.get_parent(impl_item.id)),
&sig.decl,
&impl_item.generics,
|this| intravisit::walk_impl_item(this, impl_item),
)
} else {
intravisit::walk_impl_item(self, impl_item);
use self::hir::ImplItemKind::*;
match impl_item.node {
Method(ref sig, _) => {
let tcx = self.tcx;
self.visit_early_late(
Some(tcx.hir.get_parent(impl_item.id)),
&sig.decl,
&impl_item.generics,
|this| intravisit::walk_impl_item(this, impl_item),
)
},
Type(ref ty) => {
let generics = &impl_item.generics;
let mut index = self.next_early_index();
debug!("visit_ty: index = {}", index);
let lifetimes = generics.lifetimes.iter()
.map(|lt_def| Region::early(&self.tcx.hir, &mut index, lt_def))
.collect();
let next_early_index = index + generics.ty_params.len() as u32;
let scope = Scope::Binder { lifetimes, next_early_index, s: self.scope };
self.with(scope, |_old_scope, this| {
this.visit_generics(generics);
this.visit_ty(ty);
});
},
Const(_, _) => {
// Only methods and types support generics.
assert!(!impl_item.generics.is_parameterized());
intravisit::walk_impl_item(self, impl_item);
},
}
}

6
src/test/ui/rfc1598-generic-associated-types/construct_with_other_type.rs
View File

@ -10,7 +10,8 @@
#![feature(generic_associated_types)]
//FIXME(#44265): "undeclared lifetime" errors will be addressed in a follow-up PR
//FIXME(#44265): "lifetime parameters are not allowed on this type" errors will be addressed in a
//follow-up PR
trait Foo {
type Bar<'a, 'b>;
@ -22,8 +23,7 @@ trait Baz {
impl<T> Baz for T where T: Foo {
type Quux<'a> = <T as Foo>::Bar<'a, 'static>;
//~^ ERROR undeclared lifetime
//~| ERROR lifetime parameters are not allowed on this type [E0110]
//~^ ERROR lifetime parameters are not allowed on this type [E0110]
}
fn main() {}

12
src/test/ui/rfc1598-generic-associated-types/construct_with_other_type.stderr
View File

@ -1,14 +1,8 @@
error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/construct_with_other_type.rs:24:37
|
24 | type Quux<'a> = <T as Foo>::Bar<'a, 'static>;
| ^^ undeclared lifetime
error[E0110]: lifetime parameters are not allowed on this type
--> $DIR/construct_with_other_type.rs:24:37
--> $DIR/construct_with_other_type.rs:25:37
|
24 | type Quux<'a> = <T as Foo>::Bar<'a, 'static>;
25 | type Quux<'a> = <T as Foo>::Bar<'a, 'static>;
| ^^ lifetime parameter not allowed on this type
error: aborting due to 2 previous errors
error: aborting due to previous error

3
src/test/ui/rfc1598-generic-associated-types/generic-associated-types-where.rs
View File

@ -13,8 +13,6 @@
// Checking the interaction with this other feature
#![feature(associated_type_defaults)]
//FIXME(#44265): "undeclared lifetime" errors will be addressed in a follow-up PR
use std::fmt::{Display, Debug};
trait Foo {
@ -32,7 +30,6 @@ impl Foo for Bar {
type Assoc2<T> = Vec<T>;
type Assoc3<T> where T: Iterator = Vec<T>;
type WithDefault<'a, T> = &'a Iterator<T>;
//~^ ERROR undeclared lifetime
type NoGenerics = ::std::cell::Cell<i32>;
}

6
src/test/ui/rfc1598-generic-associated-types/generic-associated-types-where.stderr
View File

@ -1,8 +1,2 @@
error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/generic-associated-types-where.rs:34:32
|
34 | type WithDefault<'a, T> = &'a Iterator<T>;
| ^^ undeclared lifetime
error: cannot continue compilation due to previous error

31
src/test/ui/rfc1598-generic-associated-types/generic_associated_type_undeclared_lifetimes.rs Normal file
View File

@ -0,0 +1,31 @@
// Copyright 2012 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(generic_associated_types)]
use std::ops::Deref;
//FIXME(#44265): "lifetime parameters are not allowed on this type" errors will be addressed in a
//follow-up PR
trait Iterable {
type Item<'a>;
type Iter<'a>: Iterator<Item = Self::Item<'a>>
//~^ ERROR lifetime parameters are not allowed on this type [E0110]
+ Deref<Target = Self::Item<'b>>;
//~^ ERROR undeclared lifetime
//~| ERROR lifetime parameters are not allowed on this type [E0110]
fn iter<'a>(&'a self) -> Self::Iter<'undeclared>;
//~^ ERROR undeclared lifetime
//~| ERROR lifetime parameters are not allowed on this type [E0110]
}
fn main() {}

32
src/test/ui/rfc1598-generic-associated-types/generic_associated_type_undeclared_lifetimes.stderr Normal file
View File

@ -0,0 +1,32 @@
error[E0261]: use of undeclared lifetime name `'b`
--> $DIR/generic_associated_type_undeclared_lifetimes.rs:22:37
|
22 | + Deref<Target = Self::Item<'b>>;
| ^^ undeclared lifetime
error[E0261]: use of undeclared lifetime name `'undeclared`
--> $DIR/generic_associated_type_undeclared_lifetimes.rs:26:41
|
26 | fn iter<'a>(&'a self) -> Self::Iter<'undeclared>;
| ^^^^^^^^^^^ undeclared lifetime
error[E0110]: lifetime parameters are not allowed on this type
--> $DIR/generic_associated_type_undeclared_lifetimes.rs:20:47
|
20 | type Iter<'a>: Iterator<Item = Self::Item<'a>>
| ^^ lifetime parameter not allowed on this type
error[E0110]: lifetime parameters are not allowed on this type
--> $DIR/generic_associated_type_undeclared_lifetimes.rs:22:37
|
22 | + Deref<Target = Self::Item<'b>>;
| ^^ lifetime parameter not allowed on this type
error[E0110]: lifetime parameters are not allowed on this type
--> $DIR/generic_associated_type_undeclared_lifetimes.rs:26:41
|
26 | fn iter<'a>(&'a self) -> Self::Iter<'undeclared>;
| ^^^^^^^^^^^ lifetime parameter not allowed on this type
error: aborting due to 5 previous errors

13
src/test/ui/rfc1598-generic-associated-types/iterable.rs
View File

@ -10,13 +10,20 @@
#![feature(generic_associated_types)]
//FIXME(#44265): "undeclared lifetime" errors will be addressed in a follow-up PR
use std::ops::Deref;
//FIXME(#44265): "lifetime parameters are not allowed on this type" errors will be addressed in a
//follow-up PR
trait Iterable {
type Item<'a>;
type Iter<'a>: Iterator<Item = Self::Item<'a>>;
//~^ ERROR undeclared lifetime
//~| ERROR lifetime parameters are not allowed on this type [E0110]
//~^ ERROR lifetime parameters are not allowed on this type [E0110]
// This weird type tests that we can use universal function call syntax to access the Item on
// Self::Iter which we have declared to be an Iterator
type Iter2<'a>: Deref<Target = <Self::Iter<'a> as Iterator>::Item>;
//~^ ERROR lifetime parameters are not allowed on this type [E0110]
fn iter<'a>(&'a self) -> Self::Iter<'a>;
//~^ ERROR lifetime parameters are not allowed on this type [E0110]

20
src/test/ui/rfc1598-generic-associated-types/iterable.stderr
View File

@ -1,19 +1,19 @@
error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/iterable.rs:17:47
|
17 | type Iter<'a>: Iterator<Item = Self::Item<'a>>;
| ^^ undeclared lifetime
error[E0110]: lifetime parameters are not allowed on this type
--> $DIR/iterable.rs:17:47
--> $DIR/iterable.rs:20:47
|
17 | type Iter<'a>: Iterator<Item = Self::Item<'a>>;
20 | type Iter<'a>: Iterator<Item = Self::Item<'a>>;
| ^^ lifetime parameter not allowed on this type
error[E0110]: lifetime parameters are not allowed on this type
--> $DIR/iterable.rs:21:41
--> $DIR/iterable.rs:25:48
|
21 | fn iter<'a>(&'a self) -> Self::Iter<'a>;
25 | type Iter2<'a>: Deref<Target = <Self::Iter<'a> as Iterator>::Item>;
| ^^ lifetime parameter not allowed on this type
error[E0110]: lifetime parameters are not allowed on this type
--> $DIR/iterable.rs:28:41
|
28 | fn iter<'a>(&'a self) -> Self::Iter<'a>;
| ^^ lifetime parameter not allowed on this type
error: aborting due to 3 previous errors