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Remove generic_associated_types_extended feature gate
1 parent 3bff51e commit 4eed6f6

24 files changed

+312
-125
lines changed

‎compiler/rustc_feature/src/removed.rs

+7
Original file line numberDiff line numberDiff line change
@@ -119,6 +119,13 @@ declare_features! (
119119
(removed, generator_clone, "1.65.0", Some(95360), Some("renamed to `coroutine_clone`")),
120120
/// Allows defining generators.
121121
(removed, generators, "1.21.0", Some(43122), Some("renamed to `coroutines`")),
122+
/// An extension to the `generic_associated_types` feature, allowing incomplete features.
123+
(removed, generic_associated_types_extended, "CURRENT_RUSTC_VERSION", Some(95451),
124+
Some(
125+
"feature needs overhaul and reimplementation pending \
126+
better implied higher-ranked implied bounds support"
127+
)
128+
),
122129
/// Allows `impl Trait` in bindings (`let`, `const`, `static`).
123130
(removed, impl_trait_in_bindings, "1.55.0", Some(63065),
124131
Some("the implementation was not maintainable, the feature may get reintroduced once the current refactorings are done")),

‎compiler/rustc_feature/src/unstable.rs

-2
Original file line numberDiff line numberDiff line change
@@ -497,8 +497,6 @@ declare_features! (
497497
(unstable, gen_blocks, "1.75.0", Some(117078)),
498498
/// Infer generic args for both consts and types.
499499
(unstable, generic_arg_infer, "1.55.0", Some(85077)),
500-
/// An extension to the `generic_associated_types` feature, allowing incomplete features.
501-
(incomplete, generic_associated_types_extended, "1.61.0", Some(95451)),
502500
/// Allows non-trivial generic constants which have to have wfness manually propagated to callers
503501
(incomplete, generic_const_exprs, "1.56.0", Some(76560)),
504502
/// Allows generic parameters and where-clauses on free & associated const items.

‎compiler/rustc_trait_selection/src/traits/dyn_compatibility.rs

+1-4
Original file line numberDiff line numberDiff line change
@@ -329,10 +329,7 @@ pub fn dyn_compatibility_violations_for_assoc_item(
329329
.collect(),
330330
// Associated types can only be dyn-compatible if they have `Self: Sized` bounds.
331331
ty::AssocKind::Type => {
332-
if !tcx.features().generic_associated_types_extended()
333-
&& !tcx.generics_of(item.def_id).is_own_empty()
334-
&& !item.is_impl_trait_in_trait()
335-
{
332+
if !tcx.generics_of(item.def_id).is_own_empty() && !item.is_impl_trait_in_trait() {
336333
vec![DynCompatibilityViolation::GAT(item.name, item.ident(tcx).span)]
337334
} else {
338335
// We will permit associated types if they are explicitly mentioned in the trait object.

‎compiler/rustc_trait_selection/src/traits/project.rs

+1-25
Original file line numberDiff line numberDiff line change
@@ -14,7 +14,7 @@ use rustc_middle::traits::select::OverflowError;
1414
use rustc_middle::traits::{BuiltinImplSource, ImplSource, ImplSourceUserDefinedData};
1515
use rustc_middle::ty::fast_reject::DeepRejectCtxt;
1616
use rustc_middle::ty::fold::TypeFoldable;
17-
use rustc_middle::ty::visit::{MaxUniverse, TypeVisitable, TypeVisitableExt};
17+
use rustc_middle::ty::visit::TypeVisitableExt;
1818
use rustc_middle::ty::{self, Term, Ty, TyCtxt, TypingMode, Upcast};
1919
use rustc_middle::{bug, span_bug};
2020
use rustc_span::symbol::sym;
@@ -179,35 +179,11 @@ pub(super) fn poly_project_and_unify_term<'cx, 'tcx>(
179179
) -> ProjectAndUnifyResult<'tcx> {
180180
let infcx = selcx.infcx;
181181
let r = infcx.commit_if_ok(|_snapshot| {
182-
let old_universe = infcx.universe();
183182
let placeholder_predicate = infcx.enter_forall_and_leak_universe(obligation.predicate);
184-
let new_universe = infcx.universe();
185183

186184
let placeholder_obligation = obligation.with(infcx.tcx, placeholder_predicate);
187185
match project_and_unify_term(selcx, &placeholder_obligation) {
188186
ProjectAndUnifyResult::MismatchedProjectionTypes(e) => Err(e),
189-
ProjectAndUnifyResult::Holds(obligations)
190-
if old_universe != new_universe
191-
&& selcx.tcx().features().generic_associated_types_extended() =>
192-
{
193-
// If the `generic_associated_types_extended` feature is active, then we ignore any
194-
// obligations references lifetimes from any universe greater than or equal to the
195-
// universe just created. Otherwise, we can end up with something like `for<'a> I: 'a`,
196-
// which isn't quite what we want. Ideally, we want either an implied
197-
// `for<'a where I: 'a> I: 'a` or we want to "lazily" check these hold when we
198-
// instantiate concrete regions. There is design work to be done here; until then,
199-
// however, this allows experimenting potential GAT features without running into
200-
// well-formedness issues.
201-
let new_obligations = obligations
202-
.into_iter()
203-
.filter(|obligation| {
204-
let mut visitor = MaxUniverse::new();
205-
obligation.predicate.visit_with(&mut visitor);
206-
visitor.max_universe() < new_universe
207-
})
208-
.collect();
209-
Ok(ProjectAndUnifyResult::Holds(new_obligations))
210-
}
211187
other => Ok(other),
212188
}
213189
});

‎compiler/rustc_trait_selection/src/traits/select/confirmation.rs

+1-1
Original file line numberDiff line numberDiff line change
@@ -626,7 +626,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
626626
for assoc_type in assoc_types {
627627
let defs: &ty::Generics = tcx.generics_of(assoc_type);
628628

629-
if !defs.own_params.is_empty() && !tcx.features().generic_associated_types_extended() {
629+
if !defs.own_params.is_empty() {
630630
tcx.dcx().span_delayed_bug(
631631
obligation.cause.span,
632632
"GATs in trait object shouldn't have been considered",

‎tests/crashes/131538.rs

-13
This file was deleted.

‎tests/ui/feature-gates/feature-gate-generic_associated_types_extended.rs

-4
This file was deleted.

‎tests/ui/feature-gates/feature-gate-generic_associated_types_extended.stderr

-12
This file was deleted.

‎tests/ui/generic-associated-types/extended/lending_iterator.rs

+2-9
Original file line numberDiff line numberDiff line change
@@ -1,17 +1,10 @@
1-
//@ revisions: base extended
2-
//@[base] check-fail
3-
//@[extended] check-pass
4-
5-
#![cfg_attr(extended, feature(generic_associated_types_extended))]
6-
#![cfg_attr(extended, allow(incomplete_features))]
7-
81
pub trait FromLendingIterator<A>: Sized {
92
fn from_iter<T: for<'x> LendingIterator<Item<'x> = A>>(iter: T) -> Self;
103
}
114

125
impl<A> FromLendingIterator<A> for Vec<A> {
136
fn from_iter<I: for<'x> LendingIterator<Item<'x> = A>>(mut iter: I) -> Self {
14-
//[base]~^ impl has stricter
7+
//~^ impl has stricter
158
let mut v = vec![];
169
while let Some(item) = iter.next() {
1710
v.push(item);
@@ -32,7 +25,7 @@ pub trait LendingIterator {
3225
Self: for<'q> LendingIterator<Item<'q> = A>,
3326
{
3427
<B as FromLendingIterator<A>>::from_iter(self)
35-
//[base]~^ ERROR: does not live long enough
28+
//~^ ERROR: does not live long enough
3629
}
3730
}
3831

‎tests/ui/generic-associated-types/extended/lending_iterator.base.stderr renamed to ‎tests/ui/generic-associated-types/extended/lending_iterator.stderr

+2-2
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
error[E0276]: impl has stricter requirements than trait
2-
--> $DIR/lending_iterator.rs:13:45
2+
--> $DIR/lending_iterator.rs:6:45
33
|
44
LL | fn from_iter<T: for<'x> LendingIterator<Item<'x> = A>>(iter: T) -> Self;
55
| ------------------------------------------------------------------------ definition of `from_iter` from trait
@@ -8,7 +8,7 @@ LL | fn from_iter<I: for<'x> LendingIterator<Item<'x> = A>>(mut iter: I) ->
88
| ^^^^^^^^^^^^ impl has extra requirement `I: 'x`
99

1010
error: `Self` does not live long enough
11-
--> $DIR/lending_iterator.rs:34:9
11+
--> $DIR/lending_iterator.rs:27:9
1212
|
1313
LL | <B as FromLendingIterator<A>>::from_iter(self)
1414
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

‎tests/ui/generic-associated-types/extended/lending_iterator_2.rs

+1-8
Original file line numberDiff line numberDiff line change
@@ -1,17 +1,10 @@
1-
//@ revisions: base extended
2-
//@[base] check-fail
3-
//@[extended] check-pass
4-
5-
#![cfg_attr(extended, feature(generic_associated_types_extended))]
6-
#![cfg_attr(extended, allow(incomplete_features))]
7-
81
pub trait FromLendingIterator<A>: Sized {
92
fn from_iter<T: for<'x> LendingIterator<Item<'x> = A>>(iter: T) -> Self;
103
}
114

125
impl<A> FromLendingIterator<A> for Vec<A> {
136
fn from_iter<I: for<'x> LendingIterator<Item<'x> = A>>(mut iter: I) -> Self {
14-
//[base]~^ impl has stricter
7+
//~^ impl has stricter
158
let mut v = vec![];
169
while let Some(item) = iter.next() {
1710
v.push(item);

‎tests/ui/generic-associated-types/extended/lending_iterator_2.stderr

+12
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,12 @@
1+
error[E0276]: impl has stricter requirements than trait
2+
--> $DIR/lending_iterator_2.rs:6:45
3+
|
4+
LL | fn from_iter<T: for<'x> LendingIterator<Item<'x> = A>>(iter: T) -> Self;
5+
| ------------------------------------------------------------------------ definition of `from_iter` from trait
6+
...
7+
LL | fn from_iter<I: for<'x> LendingIterator<Item<'x> = A>>(mut iter: I) -> Self {
8+
| ^^^^^^^^^^^^ impl has extra requirement `I: 'x`
9+
10+
error: aborting due to 1 previous error
11+
12+
For more information about this error, try `rustc --explain E0276`.

‎tests/ui/generic-associated-types/gat-in-trait-path.rs

+4-8
Original file line numberDiff line numberDiff line change
@@ -1,10 +1,6 @@
1-
//@ revisions: base extended
2-
//@[base] check-fail
3-
//@[extended] check-pass
1+
//@ check-fail
42

53
#![feature(associated_type_defaults)]
6-
#![cfg_attr(extended, feature(generic_associated_types_extended))]
7-
#![cfg_attr(extended, allow(incomplete_features))]
84

95
trait Foo {
106
type A<'a> where Self: 'a;
@@ -24,12 +20,12 @@ impl<T> Foo for Fooer<T> {
2420
}
2521

2622
fn f(_arg : Box<dyn for<'a> Foo<A<'a> = &'a ()>>) {}
27-
//[base]~^ the trait `Foo` cannot be made into an object
23+
//~^ the trait `Foo` cannot be made into an object
2824

2925

3026
fn main() {
3127
let foo = Fooer(5);
3228
f(Box::new(foo));
33-
//[base]~^ the trait `Foo` cannot be made into an object
34-
//[base]~| the trait `Foo` cannot be made into an object
29+
//~^ the trait `Foo` cannot be made into an object
30+
//~| the trait `Foo` cannot be made into an object
3531
}

‎tests/ui/generic-associated-types/gat-in-trait-path.stderr

+58
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,58 @@
1+
error[E0038]: the trait `Foo` cannot be made into an object
2+
--> $DIR/gat-in-trait-path.rs:22:17
3+
|
4+
LL | fn f(_arg : Box<dyn for<'a> Foo<A<'a> = &'a ()>>) {}
5+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
6+
|
7+
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
8+
--> $DIR/gat-in-trait-path.rs:6:10
9+
|
10+
LL | trait Foo {
11+
| --- this trait cannot be made into an object...
12+
LL | type A<'a> where Self: 'a;
13+
| ^ ...because it contains the generic associated type `A`
14+
= help: consider moving `A` to another trait
15+
= help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `Foo` for this new enum and using it instead:
16+
Fooy
17+
Fooer<T>
18+
19+
error[E0038]: the trait `Foo` cannot be made into an object
20+
--> $DIR/gat-in-trait-path.rs:28:5
21+
|
22+
LL | f(Box::new(foo));
23+
| ^^^^^^^^^^^^^ `Foo` cannot be made into an object
24+
|
25+
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
26+
--> $DIR/gat-in-trait-path.rs:6:10
27+
|
28+
LL | trait Foo {
29+
| --- this trait cannot be made into an object...
30+
LL | type A<'a> where Self: 'a;
31+
| ^ ...because it contains the generic associated type `A`
32+
= help: consider moving `A` to another trait
33+
= help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `Foo` for this new enum and using it instead:
34+
Fooy
35+
Fooer<T>
36+
37+
error[E0038]: the trait `Foo` cannot be made into an object
38+
--> $DIR/gat-in-trait-path.rs:28:5
39+
|
40+
LL | f(Box::new(foo));
41+
| ^^^^^^^^^^^^^ `Foo` cannot be made into an object
42+
|
43+
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
44+
--> $DIR/gat-in-trait-path.rs:6:10
45+
|
46+
LL | trait Foo {
47+
| --- this trait cannot be made into an object...
48+
LL | type A<'a> where Self: 'a;
49+
| ^ ...because it contains the generic associated type `A`
50+
= help: consider moving `A` to another trait
51+
= help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `Foo` for this new enum and using it instead:
52+
Fooy
53+
Fooer<T>
54+
= note: required for the cast from `Box<Fooer<{integer}>>` to `Box<(dyn Foo<A<'a> = &'a ()> + 'static)>`
55+
56+
error: aborting due to 3 previous errors
57+
58+
For more information about this error, try `rustc --explain E0038`.

‎tests/ui/generic-associated-types/issue-67510-pass.rs

+2-7
Original file line numberDiff line numberDiff line change
@@ -1,15 +1,10 @@
1-
//@ revisions: base extended
2-
//@[base] check-fail
3-
//@[extended] check-pass
4-
5-
#![cfg_attr(extended, feature(generic_associated_types_extended))]
6-
#![cfg_attr(extended, allow(incomplete_features))]
1+
//@ check-fail
72

83
trait X {
94
type Y<'a>;
105
}
116

127
fn _func1<'a>(_x: Box<dyn X<Y<'a>=&'a ()>>) {}
13-
//[base]~^ ERROR the trait `X` cannot be made into an object
8+
//~^ ERROR the trait `X` cannot be made into an object
149

1510
fn main() {}

‎tests/ui/generic-associated-types/issue-67510-pass.stderr

+18
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
1+
error[E0038]: the trait `X` cannot be made into an object
2+
--> $DIR/issue-67510-pass.rs:7:23
3+
|
4+
LL | fn _func1<'a>(_x: Box<dyn X<Y<'a>=&'a ()>>) {}
5+
| ^^^^^^^^^^^^^^^^^^^ `X` cannot be made into an object
6+
|
7+
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
8+
--> $DIR/issue-67510-pass.rs:4:10
9+
|
10+
LL | trait X {
11+
| - this trait cannot be made into an object...
12+
LL | type Y<'a>;
13+
| ^ ...because it contains the generic associated type `Y`
14+
= help: consider moving `Y` to another trait
15+
16+
error: aborting due to 1 previous error
17+
18+
For more information about this error, try `rustc --explain E0038`.

‎tests/ui/generic-associated-types/issue-76535.rs

+2-7
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,3 @@
1-
//@ revisions: base extended
2-
3-
#![cfg_attr(extended, feature(generic_associated_types_extended))]
4-
#![cfg_attr(extended, allow(incomplete_features))]
5-
61
pub trait SubTrait {}
72

83
pub trait SuperTrait {
@@ -38,6 +33,6 @@ impl SuperTrait for SuperStruct {
3833
fn main() {
3934
let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
4035
//~^ ERROR missing generics for associated type
41-
//[base]~^^ ERROR the trait
42-
//[base]~| ERROR the trait
36+
//~^^ ERROR the trait
37+
//~| ERROR the trait
4338
}

‎tests/ui/generic-associated-types/issue-76535.stderr

+55
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,55 @@
1+
error[E0107]: missing generics for associated type `SuperTrait::SubType`
2+
--> $DIR/issue-76535.rs:34:33
3+
|
4+
LL | let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
5+
| ^^^^^^^ expected 1 lifetime argument
6+
|
7+
note: associated type defined here, with 1 lifetime parameter: `'a`
8+
--> $DIR/issue-76535.rs:4:10
9+
|
10+
LL | type SubType<'a>: SubTrait where Self: 'a;
11+
| ^^^^^^^ --
12+
help: add missing lifetime argument
13+
|
14+
LL | let sub: Box<dyn SuperTrait<SubType<'a> = SubStruct>> = Box::new(SuperStruct::new(0));
15+
| ++++
16+
17+
error[E0038]: the trait `SuperTrait` cannot be made into an object
18+
--> $DIR/issue-76535.rs:34:14
19+
|
20+
LL | let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
21+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SuperTrait` cannot be made into an object
22+
|
23+
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
24+
--> $DIR/issue-76535.rs:4:10
25+
|
26+
LL | pub trait SuperTrait {
27+
| ---------- this trait cannot be made into an object...
28+
LL | type SubType<'a>: SubTrait where Self: 'a;
29+
| ^^^^^^^ ...because it contains the generic associated type `SubType`
30+
= help: consider moving `SubType` to another trait
31+
= help: only type `SuperStruct` is seen to implement the trait in this crate, consider using it directly instead
32+
= note: `SuperTrait` can be implemented in other crates; if you want to support your users passing their own types here, you can't refer to a specific type
33+
34+
error[E0038]: the trait `SuperTrait` cannot be made into an object
35+
--> $DIR/issue-76535.rs:34:57
36+
|
37+
LL | let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
38+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SuperTrait` cannot be made into an object
39+
|
40+
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
41+
--> $DIR/issue-76535.rs:4:10
42+
|
43+
LL | pub trait SuperTrait {
44+
| ---------- this trait cannot be made into an object...
45+
LL | type SubType<'a>: SubTrait where Self: 'a;
46+
| ^^^^^^^ ...because it contains the generic associated type `SubType`
47+
= help: consider moving `SubType` to another trait
48+
= help: only type `SuperStruct` is seen to implement the trait in this crate, consider using it directly instead
49+
= note: `SuperTrait` can be implemented in other crates; if you want to support your users passing their own types here, you can't refer to a specific type
50+
= note: required for the cast from `Box<SuperStruct>` to `Box<dyn SuperTrait<SubType<'_> = SubStruct<'_>>>`
51+
52+
error: aborting due to 3 previous errors
53+
54+
Some errors have detailed explanations: E0038, E0107.
55+
For more information about an error, try `rustc --explain E0038`.

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