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rust-timerrust-timer
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Unrolled build for rust-lang#133493
Rollup merge of rust-lang#133493 - lcnr:fulfill-fudge, r=compiler-errors do not constrain infer vars in `find_best_leaf_obligation` This ended up causing an ICE by making the following code path reachable by incorrectly constraining an inference variable while computing the best obligation for a preceding ambiguity. Closes rust-lang#129444. https://github.com/rust-lang/rust/blob/f2abf827c128120ed7a874d02973947968c158b8/compiler/rustc_trait_selection/src/solve/fulfill.rs#L312-L314 I have to be honest, I don't fully understand how that change removes all the additional diagnostics :3 r? `@compiler-errors`
2 parents 83965ef + fa66288 commit 0a0e1a2

13 files changed

+114
-138
lines changed

‎compiler/rustc_trait_selection/src/solve/fulfill.rs‎

Lines changed: 13 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -346,12 +346,21 @@ fn find_best_leaf_obligation<'tcx>(
346346
consider_ambiguities: bool,
347347
) -> PredicateObligation<'tcx> {
348348
let obligation = infcx.resolve_vars_if_possible(obligation.clone());
349+
// FIXME: we use a probe here as the `BestObligation` visitor does not
350+
// check whether it uses candidates which get shadowed by where-bounds.
351+
//
352+
// We should probably fix the visitor to not do so instead, as this also
353+
// means the leaf obligation may be incorrect.
349354
infcx
350-
.visit_proof_tree(obligation.clone().into(), &mut BestObligation {
351-
obligation: obligation.clone(),
352-
consider_ambiguities,
355+
.fudge_inference_if_ok(|| {
356+
infcx
357+
.visit_proof_tree(obligation.clone().into(), &mut BestObligation {
358+
obligation: obligation.clone(),
359+
consider_ambiguities,
360+
})
361+
.break_value()
362+
.ok_or(())
353363
})
354-
.break_value()
355364
.unwrap_or(obligation)
356365
}
357366

‎tests/crashes/129444.rs‎

Lines changed: 0 additions & 15 deletions
This file was deleted.

‎tests/ui/coherence/fuzzing/best-obligation-ICE.rs‎

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,20 @@
1+
// A regression test for #129444. This previously ICE'd as
2+
// computing the best obligation for one ambiguous obligation
3+
// added spurious inference constraints which caused another
4+
// candidate to pass.
5+
trait Trait {
6+
type Assoc;
7+
}
8+
9+
struct W<T: Trait>(*mut T);
10+
impl<T> Trait for W<W<W<T>>> {}
11+
//~^ ERROR the trait bound `W<W<T>>: Trait` is not satisfied
12+
//~| ERROR the trait bound `W<T>: Trait` is not satisfied
13+
//~| ERROR the trait bound `T: Trait` is not satisfied
14+
//~| ERROR not all trait items implemented, missing: `Assoc`
15+
16+
trait NoOverlap {}
17+
impl<T: Trait> NoOverlap for T {}
18+
impl<T: Trait<Assoc = u32>> NoOverlap for W<T> {}
19+
//~^ ERROR conflicting implementations of trait `NoOverlap` for type `W<W<W<W<_>>>>`
20+
fn main() {}

‎tests/ui/coherence/fuzzing/best-obligation-ICE.stderr‎

Lines changed: 69 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,69 @@
1+
error[E0277]: the trait bound `W<W<T>>: Trait` is not satisfied
2+
--> $DIR/best-obligation-ICE.rs:10:19
3+
|
4+
LL | impl<T> Trait for W<W<W<T>>> {}
5+
| ^^^^^^^^^^ the trait `Trait` is not implemented for `W<W<T>>`
6+
|
7+
note: required by a bound in `W`
8+
--> $DIR/best-obligation-ICE.rs:9:13
9+
|
10+
LL | struct W<T: Trait>(*mut T);
11+
| ^^^^^ required by this bound in `W`
12+
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
13+
|
14+
LL | impl<T> Trait for W<W<W<T>>> where W<W<T>>: Trait {}
15+
| ++++++++++++++++++++
16+
17+
error[E0277]: the trait bound `W<T>: Trait` is not satisfied
18+
--> $DIR/best-obligation-ICE.rs:10:19
19+
|
20+
LL | impl<T> Trait for W<W<W<T>>> {}
21+
| ^^^^^^^^^^ the trait `Trait` is not implemented for `W<T>`
22+
|
23+
note: required by a bound in `W`
24+
--> $DIR/best-obligation-ICE.rs:9:13
25+
|
26+
LL | struct W<T: Trait>(*mut T);
27+
| ^^^^^ required by this bound in `W`
28+
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
29+
|
30+
LL | impl<T> Trait for W<W<W<T>>> where W<T>: Trait {}
31+
| +++++++++++++++++
32+
33+
error[E0277]: the trait bound `T: Trait` is not satisfied
34+
--> $DIR/best-obligation-ICE.rs:10:19
35+
|
36+
LL | impl<T> Trait for W<W<W<T>>> {}
37+
| ^^^^^^^^^^ the trait `Trait` is not implemented for `T`
38+
|
39+
note: required by a bound in `W`
40+
--> $DIR/best-obligation-ICE.rs:9:13
41+
|
42+
LL | struct W<T: Trait>(*mut T);
43+
| ^^^^^ required by this bound in `W`
44+
help: consider restricting type parameter `T`
45+
|
46+
LL | impl<T: Trait> Trait for W<W<W<T>>> {}
47+
| +++++++
48+
49+
error[E0046]: not all trait items implemented, missing: `Assoc`
50+
--> $DIR/best-obligation-ICE.rs:10:1
51+
|
52+
LL | type Assoc;
53+
| ---------- `Assoc` from trait
54+
...
55+
LL | impl<T> Trait for W<W<W<T>>> {}
56+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `Assoc` in implementation
57+
58+
error[E0119]: conflicting implementations of trait `NoOverlap` for type `W<W<W<W<_>>>>`
59+
--> $DIR/best-obligation-ICE.rs:18:1
60+
|
61+
LL | impl<T: Trait> NoOverlap for T {}
62+
| ------------------------------ first implementation here
63+
LL | impl<T: Trait<Assoc = u32>> NoOverlap for W<T> {}
64+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `W<W<W<W<_>>>>`
65+
66+
error: aborting due to 5 previous errors
67+
68+
Some errors have detailed explanations: E0046, E0119, E0277.
69+
For more information about an error, try `rustc --explain E0046`.

‎tests/ui/impl-trait/unsized_coercion.next.stderr‎

Lines changed: 3 additions & 27 deletions
Original file line numberDiff line numberDiff line change
@@ -1,35 +1,11 @@
11
error[E0277]: the size for values of type `dyn Trait` cannot be known at compilation time
2-
--> $DIR/unsized_coercion.rs:15:17
2+
--> $DIR/unsized_coercion.rs:14:17
33
|
44
LL | let x = hello();
55
| ^^^^^^^ doesn't have a size known at compile-time
66
|
77
= help: the trait `Sized` is not implemented for `dyn Trait`
88

9-
error[E0308]: mismatched types
10-
--> $DIR/unsized_coercion.rs:19:5
11-
|
12-
LL | fn hello() -> Box<impl Trait> {
13-
| ---------------
14-
| | |
15-
| | the expected opaque type
16-
| expected `Box<impl Trait>` because of return type
17-
...
18-
LL | Box::new(1u32)
19-
| ^^^^^^^^^^^^^^ types differ
20-
|
21-
= note: expected struct `Box<impl Trait>`
22-
found struct `Box<u32>`
23-
24-
error[E0277]: the size for values of type `dyn Trait` cannot be known at compilation time
25-
--> $DIR/unsized_coercion.rs:12:1
26-
|
27-
LL | fn hello() -> Box<impl Trait> {
28-
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
29-
|
30-
= help: the trait `Sized` is not implemented for `dyn Trait`
31-
32-
error: aborting due to 3 previous errors
9+
error: aborting due to 1 previous error
3310

34-
Some errors have detailed explanations: E0277, E0308.
35-
For more information about an error, try `rustc --explain E0277`.
11+
For more information about this error, try `rustc --explain E0277`.

‎tests/ui/impl-trait/unsized_coercion.rs‎

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -10,13 +10,12 @@ trait Trait {}
1010
impl Trait for u32 {}
1111

1212
fn hello() -> Box<impl Trait> {
13-
//[next]~^ ERROR the size for values of type `dyn Trait` cannot be known at compilation time
1413
if true {
1514
let x = hello();
1615
//[next]~^ ERROR: the size for values of type `dyn Trait` cannot be known at compilation time
1716
let y: Box<dyn Trait> = x;
1817
}
19-
Box::new(1u32) //[next]~ ERROR: mismatched types
18+
Box::new(1u32)
2019
}
2120

2221
fn main() {}

‎tests/ui/impl-trait/unsized_coercion3.next.stderr‎

Lines changed: 3 additions & 27 deletions
Original file line numberDiff line numberDiff line change
@@ -1,35 +1,11 @@
11
error[E0277]: the trait bound `dyn Send: Trait` is not satisfied
2-
--> $DIR/unsized_coercion3.rs:14:17
2+
--> $DIR/unsized_coercion3.rs:13:17
33
|
44
LL | let x = hello();
55
| ^^^^^^^ the trait `Trait` is not implemented for `dyn Send`
66
|
77
= help: the trait `Trait` is implemented for `u32`
88

9-
error[E0308]: mismatched types
10-
--> $DIR/unsized_coercion3.rs:19:5
11-
|
12-
LL | fn hello() -> Box<impl Trait + ?Sized> {
13-
| ------------------------
14-
| | |
15-
| | the expected opaque type
16-
| expected `Box<impl Trait + ?Sized>` because of return type
17-
...
18-
LL | Box::new(1u32)
19-
| ^^^^^^^^^^^^^^ types differ
20-
|
21-
= note: expected struct `Box<impl Trait + ?Sized>`
22-
found struct `Box<u32>`
23-
24-
error[E0277]: the trait bound `dyn Send: Trait` is not satisfied
25-
--> $DIR/unsized_coercion3.rs:11:1
26-
|
27-
LL | fn hello() -> Box<impl Trait + ?Sized> {
28-
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for `dyn Send`
29-
|
30-
= help: the trait `Trait` is implemented for `u32`
31-
32-
error: aborting due to 3 previous errors
9+
error: aborting due to 1 previous error
3310

34-
Some errors have detailed explanations: E0277, E0308.
35-
For more information about an error, try `rustc --explain E0277`.
11+
For more information about this error, try `rustc --explain E0277`.

‎tests/ui/impl-trait/unsized_coercion3.old.stderr‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
error[E0277]: the size for values of type `impl Trait + ?Sized` cannot be known at compilation time
2-
--> $DIR/unsized_coercion3.rs:16:32
2+
--> $DIR/unsized_coercion3.rs:15:32
33
|
44
LL | let y: Box<dyn Send> = x;
55
| ^ doesn't have a size known at compile-time

‎tests/ui/impl-trait/unsized_coercion3.rs‎

Lines changed: 0 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -9,15 +9,13 @@ trait Trait {}
99
impl Trait for u32 {}
1010

1111
fn hello() -> Box<impl Trait + ?Sized> {
12-
//[next]~^ ERROR: the trait bound `dyn Send: Trait` is not satisfied
1312
if true {
1413
let x = hello();
1514
//[next]~^ ERROR: the trait bound `dyn Send: Trait` is not satisfied
1615
let y: Box<dyn Send> = x;
1716
//[old]~^ ERROR: the size for values of type `impl Trait + ?Sized` cannot be know
1817
}
1918
Box::new(1u32)
20-
//[next]~^ ERROR: mismatched types
2119
}
2220

2321
fn main() {}

‎tests/ui/traits/negative-bounds/opaque-type-unsatisfied-bound.rs‎

Lines changed: 0 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -14,13 +14,7 @@ fn main() {
1414

1515
fn weird0() -> impl Sized + !Sized {}
1616
//~^ ERROR the trait bound `(): !Sized` is not satisfied
17-
//~| ERROR the trait bound `(): !Sized` is not satisfied
18-
//~| ERROR the trait bound `(): !Sized` is not satisfied
1917
fn weird1() -> impl !Sized + Sized {}
2018
//~^ ERROR the trait bound `(): !Sized` is not satisfied
21-
//~| ERROR the trait bound `(): !Sized` is not satisfied
22-
//~| ERROR the trait bound `(): !Sized` is not satisfied
2319
fn weird2() -> impl !Sized {}
2420
//~^ ERROR the trait bound `(): !Sized` is not satisfied
25-
//~| ERROR the trait bound `(): !Sized` is not satisfied
26-
//~| ERROR the trait bound `(): !Sized` is not satisfied

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