Fix impl Trait Lifetime Handling
After this change, impl Trait existentials are desugared to a new `abstract type` definition paired with a set of lifetimes to apply. In-scope generics are included as parents of the `abstract type` generics. Parent regions are replaced with static, and parent regions referenced in the `impl Trait` type are duplicated at the end of the `abstract type`'s generics.
This commit is contained in:
Taylor Cramer
parent
d0f8e2913a
commit
bc4810d907
24 changed files with 884 additions and 133 deletions
36
src/test/compile-fail/E0657.rs
Normal file
36
src/test/compile-fail/E0657.rs
Normal file
|
|
@ -0,0 +1,36 @@
|
|||
// Copyright 2017 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.
|
||||
#![allow(warnings)]
|
||||
#![feature(conservative_impl_trait)]
|
||||
|
||||
trait Id<T> {}
|
||||
trait Lt<'a> {}
|
||||
|
||||
impl<'a> Lt<'a> for () {}
|
||||
impl<T> Id<T> for T {}
|
||||
|
||||
fn free_fn_capture_hrtb_in_impl_trait()
|
||||
-> impl for<'a> Id<impl Lt<'a>>
|
||||
//~^ ERROR `impl Trait` can only capture lifetimes bound at the fn or impl level [E0657]
|
||||
{
|
||||
()
|
||||
}
|
||||
|
||||
struct Foo;
|
||||
impl Foo {
|
||||
fn impl_fn_capture_hrtb_in_impl_trait()
|
||||
-> impl for<'a> Id<impl Lt<'a>>
|
||||
//~^ ERROR `impl Trait` can only capture lifetimes bound at the fn or impl level
|
||||
{
|
||||
()
|
||||
}
|
||||
}
|
||||
|
||||
fn main() {}
|
||||
|
|
@ -1,43 +0,0 @@
|
|||
// Copyright 2016 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(conservative_impl_trait)]
|
||||
|
||||
// Helper creating a fake borrow, captured by the impl Trait.
|
||||
fn borrow<'a, T>(_: &'a mut T) -> impl Copy { () }
|
||||
|
||||
fn stack() -> impl Copy {
|
||||
//~^ ERROR only named lifetimes are allowed in `impl Trait`
|
||||
let x = 0;
|
||||
&x
|
||||
}
|
||||
|
||||
fn late_bound(x: &i32) -> impl Copy {
|
||||
//~^ ERROR only named lifetimes are allowed in `impl Trait`
|
||||
x
|
||||
}
|
||||
|
||||
// FIXME(#34511) Should work but doesn't at the moment,
|
||||
// region-checking needs an overhault to support this.
|
||||
fn early_bound<'a>(x: &'a i32) -> impl Copy {
|
||||
//~^ ERROR only named lifetimes are allowed in `impl Trait`
|
||||
x
|
||||
}
|
||||
|
||||
fn ambiguous<'a, 'b>(x: &'a [u32], y: &'b [u32]) -> impl Iterator<Item=u32> {
|
||||
//~^ ERROR only named lifetimes are allowed in `impl Trait`
|
||||
if x.len() < y.len() {
|
||||
x.iter().cloned()
|
||||
} else {
|
||||
y.iter().cloned()
|
||||
}
|
||||
}
|
||||
|
||||
fn main() {}
|
||||
|
|
@ -0,0 +1,39 @@
|
|||
// Copyright 2017 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(conservative_impl_trait)]
|
||||
|
||||
use std::fmt::Debug;
|
||||
|
||||
fn elided(x: &i32) -> impl Copy { x }
|
||||
//~^ ERROR cannot infer an appropriate lifetime
|
||||
|
||||
fn explicit<'a>(x: &'a i32) -> impl Copy { x }
|
||||
//~^ ERROR cannot infer an appropriate lifetime
|
||||
|
||||
trait LifetimeTrait<'a> {}
|
||||
impl<'a> LifetimeTrait<'a> for &'a i32 {}
|
||||
|
||||
fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x }
|
||||
//~^ ERROR cannot infer an appropriate lifetime
|
||||
|
||||
// Tests that a closure type contianing 'b cannot be returned from a type where
|
||||
// only 'a was expected.
|
||||
fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32) {
|
||||
//~^ ERROR lifetime mismatch
|
||||
move |_| println!("{}", y)
|
||||
}
|
||||
|
||||
fn ty_param_wont_outlive_static<T:Debug>(x: T) -> impl Debug + 'static {
|
||||
//~^ ERROR the parameter type `T` may not live long enough
|
||||
x
|
||||
}
|
||||
|
||||
fn main() {}
|
||||
|
|
@ -0,0 +1,23 @@
|
|||
// Copyright 2017 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(conservative_impl_trait)]
|
||||
|
||||
use std::fmt::Debug;
|
||||
|
||||
trait MultiRegionTrait<'a, 'b> {}
|
||||
impl<'a, 'b> MultiRegionTrait<'a, 'b> for (&'a u32, &'b u32) {}
|
||||
|
||||
fn no_least_region<'a, 'b>(x: &'a u32, y: &'b u32) -> impl MultiRegionTrait<'a, 'b> {
|
||||
//~^ ERROR ambiguous lifetime bound
|
||||
(x, y)
|
||||
}
|
||||
|
||||
fn main() {}
|
||||
24
src/test/compile-fail/impl-trait/type_parameters_captured.rs
Normal file
24
src/test/compile-fail/impl-trait/type_parameters_captured.rs
Normal file
|
|
@ -0,0 +1,24 @@
|
|||
// Copyright 2017 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(conservative_impl_trait)]
|
||||
|
||||
use std::fmt::Debug;
|
||||
|
||||
trait Any {}
|
||||
impl<T> Any for T {}
|
||||
|
||||
// Check that type parameters are captured and not considered 'static
|
||||
fn foo<T>(x: T) -> impl Any + 'static {
|
||||
//~^ ERROR the parameter type `T` may not live long enough
|
||||
x
|
||||
}
|
||||
|
||||
fn main() {}
|
||||
97
src/test/run-pass/impl-trait/lifetimes.rs
Normal file
97
src/test/run-pass/impl-trait/lifetimes.rs
Normal file
|
|
@ -0,0 +1,97 @@
|
|||
// Copyright 2017 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(conservative_impl_trait)]
|
||||
#![allow(warnings)]
|
||||
|
||||
use std::fmt::Debug;
|
||||
|
||||
fn any_lifetime<'a>() -> &'a u32 { &5 }
|
||||
|
||||
fn static_lifetime() -> &'static u32 { &5 }
|
||||
|
||||
fn any_lifetime_as_static_impl_trait() -> impl Debug {
|
||||
any_lifetime()
|
||||
}
|
||||
|
||||
fn lifetimes_as_static_impl_trait() -> impl Debug {
|
||||
static_lifetime()
|
||||
}
|
||||
|
||||
fn no_params_or_lifetimes_is_static() -> impl Debug + 'static {
|
||||
lifetimes_as_static_impl_trait()
|
||||
}
|
||||
|
||||
fn static_input_type_is_static<T: Debug + 'static>(x: T) -> impl Debug + 'static { x }
|
||||
|
||||
fn type_outlives_reference_lifetime<'a, T: Debug>(x: &'a T) -> impl Debug + 'a { x }
|
||||
|
||||
trait SingleRegionTrait<'a> {}
|
||||
impl<'a> SingleRegionTrait<'a> for u32 {}
|
||||
|
||||
fn simple_type_hrtb<'b>() -> impl for<'a> SingleRegionTrait<'a> { 5 }
|
||||
fn closure_hrtb() -> impl for<'a> Fn(&'a u32) { |_| () }
|
||||
|
||||
fn mixed_lifetimes<'a>() -> impl for<'b: 'a> Fn(&'b u32) { |_| () }
|
||||
fn mixed_as_static() -> impl Fn(&'static u32) { mixed_lifetimes() }
|
||||
|
||||
trait MultiRegionTrait<'a, 'b>: Debug {}
|
||||
|
||||
#[derive(Debug)]
|
||||
struct MultiRegionStruct<'a, 'b>(&'a u32, &'b u32);
|
||||
impl<'a, 'b> MultiRegionTrait<'a, 'b> for MultiRegionStruct<'a, 'b> {}
|
||||
|
||||
#[derive(Debug)]
|
||||
struct NoRegionStruct;
|
||||
impl<'a, 'b> MultiRegionTrait<'a, 'b> for NoRegionStruct {}
|
||||
|
||||
fn finds_least_region<'a: 'b, 'b>(x: &'a u32, y: &'b u32) -> impl MultiRegionTrait<'a, 'b> {
|
||||
MultiRegionStruct(x, y)
|
||||
}
|
||||
|
||||
fn finds_explicit_bound<'a: 'b, 'b>
|
||||
(x: &'a u32, y: &'b u32) -> impl MultiRegionTrait<'a, 'b> + 'b
|
||||
{
|
||||
MultiRegionStruct(x, y)
|
||||
}
|
||||
|
||||
fn finds_explicit_bound_even_without_least_region<'a, 'b>
|
||||
(x: &'a u32, y: &'b u32) -> impl MultiRegionTrait<'a, 'b> + 'b
|
||||
{
|
||||
NoRegionStruct
|
||||
}
|
||||
|
||||
/* FIXME: `impl Trait<'a> + 'b` should live as long as 'b, even if 'b outlives 'a
|
||||
fn outlives_bounds_even_with_contained_regions<'a, 'b>
|
||||
(x: &'a u32, y: &'b u32) -> impl Debug + 'b
|
||||
{
|
||||
finds_explicit_bound_even_without_least_region(x, y)
|
||||
}
|
||||
*/
|
||||
|
||||
fn unnamed_lifetimes_arent_contained_in_impl_trait_and_will_unify<'a, 'b>
|
||||
(x: &'a u32, y: &'b u32) -> impl Debug
|
||||
{
|
||||
fn deref<'lt>(x: &'lt u32) -> impl Debug { *x }
|
||||
|
||||
if true { deref(x) } else { deref(y) }
|
||||
}
|
||||
|
||||
fn can_add_region_bound_to_static_type<'a, 'b>(_: &'a u32) -> impl Debug + 'a { 5 }
|
||||
|
||||
struct MyVec(Vec<Vec<u8>>);
|
||||
|
||||
impl<'unnecessary_lifetime> MyVec {
|
||||
fn iter_doesnt_capture_unnecessary_lifetime<'s>(&'s self) -> impl Iterator<Item = &'s u8> {
|
||||
self.0.iter().flat_map(|inner_vec| inner_vec.iter())
|
||||
}
|
||||
}
|
||||
|
||||
fn main() {}
|
||||
|
|
@ -1,24 +0,0 @@
|
|||
// Copyright 2016 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(conservative_impl_trait)]
|
||||
|
||||
// Helper creating a fake borrow, captured by the impl Trait.
|
||||
fn borrow<'a, T>(_: &'a mut T) -> impl Copy { () }
|
||||
|
||||
fn main() {
|
||||
let long;
|
||||
let mut short = 0;
|
||||
long = borrow(&mut short);
|
||||
//~^ NOTE borrow occurs here
|
||||
}
|
||||
//~^ ERROR `short` does not live long enough
|
||||
//~| NOTE `short` dropped here while still borrowed
|
||||
//~| NOTE values in a scope are dropped in the opposite order they are created
|
||||
Loading…
Add table
Add a link
Reference in a new issue