Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly
Sign up
Appearance settings

Commit 7e19eef

Browse files
committed
Auto merge of #140557 - compiler-errors:remove-wf-hack, r=lcnr
Remove manual WF hack We do not need this hack anymore since we fixed the candidate selection problems with `Sized` bounds. We prefer built-in sized bounds now since #138176, which fixes the only regression this hack was intended to fix. While this theoretically is broken for some code, for example, when there a param-env bound that shadows an impl or built-in trait, we don't see it in practice and IMO it's not worth the burden of having to maintain this wart in `compare_method_predicate_entailment`. The code that regresses is, for example: ```rust trait Bar<'a> {} trait Foo<'a, T> { fn method(&self) where Self: Bar<'a>; } struct W<'a, T>(&'a T) where Self: Bar<'a>; impl<'a, 'b, T> Bar<'a> for W<'b, T> {} impl<'a, 'b, T> Foo<'a, T> for W<'b, T> { fn method(&self) {} } ``` Specifically, I don't believe this is really going to be encountered in practice. For this to fail, there must be a where clause in the *trait method* that would shadow an impl or built-in (non-`Sized`) candidate in the trait, and this shadowing would need to be encountered when solving a nested WF goal from the impl self type. See #108544 for the original regression. Crater run is clean! r? lcnr
2 parents 6d1875f + df47958 commit 7e19eef

File tree

7 files changed

+89
-72
lines changed

7 files changed

+89
-72
lines changed

‎compiler/rustc_hir_analysis/src/check/compare_impl_item.rs‎

Lines changed: 9 additions & 56 deletions
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@ use std::borrow::Cow;
33
use std::iter;
44

55
use hir::def_id::{DefId, DefIdMap, LocalDefId};
6-
use rustc_data_structures::fx::{FxHashSet,FxIndexMap, FxIndexSet};
6+
use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
77
use rustc_errors::codes::*;
88
use rustc_errors::{Applicability, ErrorGuaranteed, MultiSpan, pluralize, struct_span_code_err};
99
use rustc_hir::def::{DefKind, Res};
@@ -356,61 +356,14 @@ fn compare_method_predicate_entailment<'tcx>(
356356
}
357357

358358
if !(impl_sig, trait_sig).references_error() {
359-
// Select obligations to make progress on inference before processing
360-
// the wf obligation below.
361-
// FIXME(-Znext-solver): Not needed when the hack below is removed.
362-
let errors = ocx.select_where_possible();
363-
if !errors.is_empty() {
364-
let reported = infcx.err_ctxt().report_fulfillment_errors(errors);
365-
return Err(reported);
366-
}
367-
368-
// See #108544. Annoying, we can end up in cases where, because of winnowing,
369-
// we pick param env candidates over a more general impl, leading to more
370-
// stricter lifetime requirements than we would otherwise need. This can
371-
// trigger the lint. Instead, let's only consider type outlives and
372-
// region outlives obligations.
373-
//
374-
// FIXME(-Znext-solver): Try removing this hack again once the new
375-
// solver is stable. We should just be able to register a WF pred for
376-
// the fn sig.
377-
let mut wf_args: smallvec::SmallVec<[_; 4]> =
378-
unnormalized_impl_sig.inputs_and_output.iter().map(|ty| ty.into()).collect();
379-
// Annoyingly, asking for the WF predicates of an array (with an unevaluated const (only?))
380-
// will give back the well-formed predicate of the same array.
381-
let mut wf_args_seen: FxHashSet<_> = wf_args.iter().copied().collect();
382-
while let Some(term) = wf_args.pop() {
383-
let Some(obligations) = rustc_trait_selection::traits::wf::obligations(
384-
infcx,
385-
param_env,
386-
impl_m_def_id,
387-
0,
388-
term,
389-
impl_m_span,
390-
) else {
391-
continue;
392-
};
393-
for obligation in obligations {
394-
debug!(?obligation);
395-
match obligation.predicate.kind().skip_binder() {
396-
// We need to register Projection oblgiations too, because we may end up with
397-
// an implied `X::Item: 'a`, which gets desugared into `X::Item = ?0`, `?0: 'a`.
398-
// If we only register the region outlives obligation, this leads to an unconstrained var.
399-
// See `implied_bounds_entailment_alias_var.rs` test.
400-
ty::PredicateKind::Clause(
401-
ty::ClauseKind::RegionOutlives(..)
402-
| ty::ClauseKind::TypeOutlives(..)
403-
| ty::ClauseKind::Projection(..),
404-
) => ocx.register_obligation(obligation),
405-
ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(term)) => {
406-
if wf_args_seen.insert(term) {
407-
wf_args.push(term)
408-
}
409-
}
410-
_ => {}
411-
}
412-
}
413-
}
359+
ocx.register_obligation(traits::Obligation::new(
360+
infcx.tcx,
361+
cause,
362+
param_env,
363+
ty::ClauseKind::WellFormed(
364+
Ty::new_fn_ptr(tcx, ty::Binder::dummy(unnormalized_impl_sig)).into(),
365+
),
366+
));
414367
}
415368

416369
// Check that all obligations are satisfied by the implementation's

‎tests/incremental/const-generics/try_unify_abstract_const_regression_tests/issue-88022.rs‎

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -15,12 +15,14 @@ where
1515

1616
impl<'a, T, const S: usize> Iterator for BufferIter<'a, T, S> {
1717
//~^ error: the trait bound
18-
//~^^ error: unconstrained generic constant
18+
//~| error: unconstrained generic constant
1919
type Item = &'a T;
2020

2121
fn next(&mut self) -> Option<Self::Item> {
2222
//~^ error: the trait bound
23-
//~^^ error: unconstrained generic constant
23+
//~| error: unconstrained generic constant
24+
//~| error: the trait bound
25+
//~| error: unconstrained generic constant
2426
None
2527
}
2628
}

‎tests/ui/dropck/explicit-drop-bounds.bad1.stderr‎

Lines changed: 17 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -14,6 +14,22 @@ help: consider further restricting type parameter `T` with trait `Copy`
1414
LL | [T; 1]: Copy, T: std::marker::Copy // But `[T; 1]: Copy` does not imply `T: Copy`
1515
| ++++++++++++++++++++
1616

17+
error[E0277]: the trait bound `T: Copy` is not satisfied
18+
--> $DIR/explicit-drop-bounds.rs:32:5
19+
|
20+
LL | fn drop(&mut self) {}
21+
| ^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `T`
22+
|
23+
note: required by a bound in `DropMe`
24+
--> $DIR/explicit-drop-bounds.rs:7:18
25+
|
26+
LL | struct DropMe<T: Copy>(T);
27+
| ^^^^ required by this bound in `DropMe`
28+
help: consider further restricting type parameter `T` with trait `Copy`
29+
|
30+
LL | [T; 1]: Copy, T: std::marker::Copy // But `[T; 1]: Copy` does not imply `T: Copy`
31+
| ++++++++++++++++++++
32+
1733
error[E0277]: the trait bound `T: Copy` is not satisfied
1834
--> $DIR/explicit-drop-bounds.rs:32:18
1935
|
@@ -30,6 +46,6 @@ help: consider further restricting type parameter `T` with trait `Copy`
3046
LL | [T; 1]: Copy, T: std::marker::Copy // But `[T; 1]: Copy` does not imply `T: Copy`
3147
| ++++++++++++++++++++
3248

33-
error: aborting due to 2 previous errors
49+
error: aborting due to 3 previous errors
3450

3551
For more information about this error, try `rustc --explain E0277`.

‎tests/ui/dropck/explicit-drop-bounds.bad2.stderr‎

Lines changed: 19 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
error[E0277]: the trait bound `T: Copy` is not satisfied
2-
--> $DIR/explicit-drop-bounds.rs:37:18
2+
--> $DIR/explicit-drop-bounds.rs:38:18
33
|
44
LL | impl<T> Drop for DropMe<T>
55
| ^^^^^^^^^ the trait `Copy` is not implemented for `T`
@@ -15,7 +15,23 @@ LL | impl<T: std::marker::Copy> Drop for DropMe<T>
1515
| +++++++++++++++++++
1616

1717
error[E0277]: the trait bound `T: Copy` is not satisfied
18-
--> $DIR/explicit-drop-bounds.rs:40:18
18+
--> $DIR/explicit-drop-bounds.rs:41:5
19+
|
20+
LL | fn drop(&mut self) {}
21+
| ^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `T`
22+
|
23+
note: required by a bound in `DropMe`
24+
--> $DIR/explicit-drop-bounds.rs:7:18
25+
|
26+
LL | struct DropMe<T: Copy>(T);
27+
| ^^^^ required by this bound in `DropMe`
28+
help: consider restricting type parameter `T` with trait `Copy`
29+
|
30+
LL | impl<T: std::marker::Copy> Drop for DropMe<T>
31+
| +++++++++++++++++++
32+
33+
error[E0277]: the trait bound `T: Copy` is not satisfied
34+
--> $DIR/explicit-drop-bounds.rs:41:18
1935
|
2036
LL | fn drop(&mut self) {}
2137
| ^^^^ the trait `Copy` is not implemented for `T`
@@ -30,6 +46,6 @@ help: consider restricting type parameter `T` with trait `Copy`
3046
LL | impl<T: std::marker::Copy> Drop for DropMe<T>
3147
| +++++++++++++++++++
3248

33-
error: aborting due to 2 previous errors
49+
error: aborting due to 3 previous errors
3450

3551
For more information about this error, try `rustc --explain E0277`.

‎tests/ui/dropck/explicit-drop-bounds.rs‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -31,6 +31,7 @@ where
3131
{
3232
fn drop(&mut self) {}
3333
//[bad1]~^ ERROR the trait bound `T: Copy` is not satisfied
34+
//[bad1]~| ERROR the trait bound `T: Copy` is not satisfied
3435
}
3536

3637
#[cfg(bad2)]
@@ -39,6 +40,7 @@ impl<T> Drop for DropMe<T>
3940
{
4041
fn drop(&mut self) {}
4142
//[bad2]~^ ERROR the trait bound `T: Copy` is not satisfied
43+
//[bad2]~| ERROR the trait bound `T: Copy` is not satisfied
4244
}
4345

4446
fn main() {}

‎tests/ui/layout/rust-call-abi-not-a-tuple-ice-81974.rs‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -30,7 +30,8 @@ where
3030
type Output = B;
3131
extern "rust-call" fn call_once(mut self, a: A) -> Self::Output {
3232
//~^ ERROR functions with the "rust-call" ABI must take a single non-self tuple argument
33-
self.call_mut(a)
33+
//~| ERROR type parameter to bare `FnOnce` trait must be a tuple
34+
self.call_mut(a)
3435
//~^ ERROR `A` is not a tuple
3536
}
3637
}
@@ -43,6 +44,7 @@ where
4344
{
4445
extern "rust-call" fn call_mut(&mut self, a: A) -> Self::Output {
4546
//~^ ERROR functions with the "rust-call" ABI must take a single non-self tuple argument
47+
//~| ERROR type parameter to bare `FnOnce` trait must be a tuple
4648
self.cache.get(&a).map(|a| a.clone()).unwrap_or_else(|| {
4749
let b = (self.fun)(self, a.clone());
4850
self.cache.insert(a, b.clone());

‎tests/ui/layout/rust-call-abi-not-a-tuple-ice-81974.stderr‎

Lines changed: 35 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -11,8 +11,21 @@ help: consider further restricting type parameter `A` with unstable trait `Tuple
1111
LL | A: Eq + Hash + Clone + std::marker::Tuple,
1212
| ++++++++++++++++++++
1313

14+
error[E0059]: type parameter to bare `FnOnce` trait must be a tuple
15+
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:31:5
16+
|
17+
LL | extern "rust-call" fn call_once(mut self, a: A) -> Self::Output {
18+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Tuple` is not implemented for `A`
19+
|
20+
note: required by a bound in `FnOnce`
21+
--> $SRC_DIR/core/src/ops/function.rs:LL:COL
22+
help: consider further restricting type parameter `A` with unstable trait `Tuple`
23+
|
24+
LL | A: Eq + Hash + Clone + std::marker::Tuple,
25+
| ++++++++++++++++++++
26+
1427
error[E0059]: type parameter to bare `FnMut` trait must be a tuple
15-
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:38:12
28+
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:39:12
1629
|
1730
LL | impl<A, B> FnMut<A> for CachedFun<A, B>
1831
| ^^^^^^^^ the trait `Tuple` is not implemented for `A`
@@ -24,6 +37,19 @@ help: consider further restricting type parameter `A` with unstable trait `Tuple
2437
LL | A: Eq + Hash + Clone + std::marker::Tuple,
2538
| ++++++++++++++++++++
2639

40+
error[E0059]: type parameter to bare `FnOnce` trait must be a tuple
41+
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:45:5
42+
|
43+
LL | extern "rust-call" fn call_mut(&mut self, a: A) -> Self::Output {
44+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Tuple` is not implemented for `A`
45+
|
46+
note: required by a bound in `FnOnce`
47+
--> $SRC_DIR/core/src/ops/function.rs:LL:COL
48+
help: consider further restricting type parameter `A` with unstable trait `Tuple`
49+
|
50+
LL | A: Eq + Hash + Clone + std::marker::Tuple,
51+
| ++++++++++++++++++++
52+
2753
error[E0277]: functions with the "rust-call" ABI must take a single non-self tuple argument
2854
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:31:5
2955
|
@@ -36,7 +62,7 @@ LL | A: Eq + Hash + Clone + std::marker::Tuple,
3662
| ++++++++++++++++++++
3763

3864
error[E0277]: functions with the "rust-call" ABI must take a single non-self tuple argument
39-
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:44:5
65+
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:45:5
4066
|
4167
LL | extern "rust-call" fn call_mut(&mut self, a: A) -> Self::Output {
4268
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Tuple` is not implemented for `A`
@@ -47,12 +73,12 @@ LL | A: Eq + Hash + Clone + std::marker::Tuple,
4773
| ++++++++++++++++++++
4874

4975
error[E0277]: `A` is not a tuple
50-
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:33:23
76+
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:34:19
5177
|
52-
LL | self.call_mut(a)
53-
| -------- ^ the trait `Tuple` is not implemented for `A`
54-
| |
55-
| required by a bound introduced by this call
78+
LL | self.call_mut(a)
79+
| -------- ^ the trait `Tuple` is not implemented for `A`
80+
| |
81+
| required by a bound introduced by this call
5682
|
5783
note: required by a bound in `call_mut`
5884
--> $SRC_DIR/core/src/ops/function.rs:LL:COL
@@ -62,7 +88,7 @@ LL | A: Eq + Hash + Clone + std::marker::Tuple,
6288
| ++++++++++++++++++++
6389

6490
error[E0277]: `i32` is not a tuple
65-
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:57:26
91+
--> $DIR/rust-call-abi-not-a-tuple-ice-81974.rs:59:26
6692
|
6793
LL | cachedcoso.call_once(1);
6894
| --------- ^ the trait `Tuple` is not implemented for `i32`
@@ -76,7 +102,7 @@ help: use a unary tuple instead
76102
LL | cachedcoso.call_once((1,));
77103
| + ++
78104

79-
error: aborting due to 6 previous errors
105+
error: aborting due to 8 previous errors
80106

81107
Some errors have detailed explanations: E0059, E0277.
82108
For more information about an error, try `rustc --explain E0059`.

0 commit comments

Comments
(0)

AltStyle によって変換されたページ (->オリジナル) /