mathieu/os-rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Rollup merge of #133493 - lcnr:fulfill-fudge, r=compiler-errors

Browse source 
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 #129444.

f2abf827c1/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`
This commit is contained in:
Matthias Krüger 2024-11-27 08:13:49 +01:00 • committed by GitHub
commit 762a661705
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
13 changed files with 114 additions and 138 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

17
compiler/rustc_trait_selection/src/solve/fulfill.rs
View file

@ -346,12 +346,21 @@ fn find_best_leaf_obligation<'tcx>(
consider_ambiguities: bool,
) -> PredicateObligation<'tcx> {
let obligation = infcx.resolve_vars_if_possible(obligation.clone());
// FIXME: we use a probe here as the `BestObligation` visitor does not
// check whether it uses candidates which get shadowed by where-bounds.
//
// We should probably fix the visitor to not do so instead, as this also
// means the leaf obligation may be incorrect.
infcx
.visit_proof_tree(obligation.clone().into(), &mut BestObligation {
obligation: obligation.clone(),
consider_ambiguities,
.fudge_inference_if_ok(|| {
infcx
.visit_proof_tree(obligation.clone().into(), &mut BestObligation {
obligation: obligation.clone(),
consider_ambiguities,
})
.break_value()
.ok_or(())
})
.break_value()
.unwrap_or(obligation)
}

15
tests/crashes/129444.rs
View file

@ -1,15 +0,0 @@
//@ known-bug: rust-lang/rust#129444
//@ compile-flags: -Znext-solver=coherence
trait Trait {
type Assoc;
}
struct W<T: Trait>(*mut T);
impl<T: ?Trait> Trait for W<W<W<T>>> {}
trait NoOverlap {}
impl<T: Trait<W<T>>> NoOverlap for T {}
impl<T: Trait<Assoc = u32>> NoOverlap for W<T> {}

20
tests/ui/coherence/fuzzing/best-obligation-ICE.rs Normal file
View file

@ -0,0 +1,20 @@
// A regression test for #129444. This previously ICE'd as
// computing the best obligation for one ambiguous obligation
// added spurious inference constraints which caused another
// candidate to pass.
trait Trait {
type Assoc;
}
struct W<T: Trait>(*mut T);
impl<T> Trait for W<W<W<T>>> {}
//~^ ERROR the trait bound `W<W<T>>: Trait` is not satisfied
//~| ERROR the trait bound `W<T>: Trait` is not satisfied
//~| ERROR the trait bound `T: Trait` is not satisfied
//~| ERROR not all trait items implemented, missing: `Assoc`
trait NoOverlap {}
impl<T: Trait> NoOverlap for T {}
impl<T: Trait<Assoc = u32>> NoOverlap for W<T> {}
//~^ ERROR conflicting implementations of trait `NoOverlap` for type `W<W<W<W<_>>>>`
fn main() {}

69
tests/ui/coherence/fuzzing/best-obligation-ICE.stderr Normal file
View file

@ -0,0 +1,69 @@
error[E0277]: the trait bound `W<W<T>>: Trait` is not satisfied
--> $DIR/best-obligation-ICE.rs:10:19
|
LL | impl<T> Trait for W<W<W<T>>> {}
| ^^^^^^^^^^ the trait `Trait` is not implemented for `W<W<T>>`
|
note: required by a bound in `W`
--> $DIR/best-obligation-ICE.rs:9:13
|
LL | struct W<T: Trait>(*mut T);
| ^^^^^ required by this bound in `W`
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
|
LL | impl<T> Trait for W<W<W<T>>> where W<W<T>>: Trait {}
| ++++++++++++++++++++
error[E0277]: the trait bound `W<T>: Trait` is not satisfied
--> $DIR/best-obligation-ICE.rs:10:19
|
LL | impl<T> Trait for W<W<W<T>>> {}
| ^^^^^^^^^^ the trait `Trait` is not implemented for `W<T>`
|
note: required by a bound in `W`
--> $DIR/best-obligation-ICE.rs:9:13
|
LL | struct W<T: Trait>(*mut T);
| ^^^^^ required by this bound in `W`
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
|
LL | impl<T> Trait for W<W<W<T>>> where W<T>: Trait {}
| +++++++++++++++++
error[E0277]: the trait bound `T: Trait` is not satisfied
--> $DIR/best-obligation-ICE.rs:10:19
|
LL | impl<T> Trait for W<W<W<T>>> {}
| ^^^^^^^^^^ the trait `Trait` is not implemented for `T`
|
note: required by a bound in `W`
--> $DIR/best-obligation-ICE.rs:9:13
|
LL | struct W<T: Trait>(*mut T);
| ^^^^^ required by this bound in `W`
help: consider restricting type parameter `T`
|
LL | impl<T: Trait> Trait for W<W<W<T>>> {}
| +++++++
error[E0046]: not all trait items implemented, missing: `Assoc`
--> $DIR/best-obligation-ICE.rs:10:1
|
LL | type Assoc;
| ---------- `Assoc` from trait
...
LL | impl<T> Trait for W<W<W<T>>> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `Assoc` in implementation
error[E0119]: conflicting implementations of trait `NoOverlap` for type `W<W<W<W<_>>>>`
--> $DIR/best-obligation-ICE.rs:18:1
|
LL | impl<T: Trait> NoOverlap for T {}
| ------------------------------ first implementation here
LL | impl<T: Trait<Assoc = u32>> NoOverlap for W<T> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `W<W<W<W<_>>>>`
error: aborting due to 5 previous errors
Some errors have detailed explanations: E0046, E0119, E0277.
For more information about an error, try `rustc --explain E0046`.

30
tests/ui/impl-trait/unsized_coercion.next.stderr
View file

@ -1,35 +1,11 @@
error[E0277]: the size for values of type `dyn Trait` cannot be known at compilation time
--> $DIR/unsized_coercion.rs:15:17
--> $DIR/unsized_coercion.rs:14:17
|
LL | let x = hello();
| ^^^^^^^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `dyn Trait`
error[E0308]: mismatched types
--> $DIR/unsized_coercion.rs:19:5
|
LL | fn hello() -> Box<impl Trait> {
| ---------------
| | |
| | the expected opaque type
| expected `Box<impl Trait>` because of return type
...
LL | Box::new(1u32)
| ^^^^^^^^^^^^^^ types differ
|
= note: expected struct `Box<impl Trait>`
found struct `Box<u32>`
error: aborting due to 1 previous error
error[E0277]: the size for values of type `dyn Trait` cannot be known at compilation time
--> $DIR/unsized_coercion.rs:12:1
|
LL | fn hello() -> Box<impl Trait> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `dyn Trait`
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0277, E0308.
For more information about an error, try `rustc --explain E0277`.
For more information about this error, try `rustc --explain E0277`.

3
tests/ui/impl-trait/unsized_coercion.rs
View file

@ -10,13 +10,12 @@ trait Trait {}
impl Trait for u32 {}
fn hello() -> Box<impl Trait> {
//[next]~^ ERROR the size for values of type `dyn Trait` cannot be known at compilation time
if true {
let x = hello();
//[next]~^ ERROR: the size for values of type `dyn Trait` cannot be known at compilation time
let y: Box<dyn Trait> = x;
}
Box::new(1u32) //[next]~ ERROR: mismatched types
Box::new(1u32)
}
fn main() {}

30
tests/ui/impl-trait/unsized_coercion3.next.stderr
View file

@ -1,35 +1,11 @@
error[E0277]: the trait bound `dyn Send: Trait` is not satisfied
--> $DIR/unsized_coercion3.rs:14:17
--> $DIR/unsized_coercion3.rs:13:17
|
LL | let x = hello();
| ^^^^^^^ the trait `Trait` is not implemented for `dyn Send`
|
= help: the trait `Trait` is implemented for `u32`
error[E0308]: mismatched types
--> $DIR/unsized_coercion3.rs:19:5
|
LL | fn hello() -> Box<impl Trait + ?Sized> {
| ------------------------
| | |
| | the expected opaque type
| expected `Box<impl Trait + ?Sized>` because of return type
...
LL | Box::new(1u32)
| ^^^^^^^^^^^^^^ types differ
|
= note: expected struct `Box<impl Trait + ?Sized>`
found struct `Box<u32>`
error: aborting due to 1 previous error
error[E0277]: the trait bound `dyn Send: Trait` is not satisfied
--> $DIR/unsized_coercion3.rs:11:1
|
LL | fn hello() -> Box<impl Trait + ?Sized> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for `dyn Send`
|
= help: the trait `Trait` is implemented for `u32`
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0277, E0308.
For more information about an error, try `rustc --explain E0277`.
For more information about this error, try `rustc --explain E0277`.

2
tests/ui/impl-trait/unsized_coercion3.old.stderr
View file

@ -1,5 +1,5 @@
error[E0277]: the size for values of type `impl Trait + ?Sized` cannot be known at compilation time
--> $DIR/unsized_coercion3.rs:16:32
--> $DIR/unsized_coercion3.rs:15:32
|
LL | let y: Box<dyn Send> = x;
| ^ doesn't have a size known at compile-time

2
tests/ui/impl-trait/unsized_coercion3.rs
View file

@ -9,7 +9,6 @@ trait Trait {}
impl Trait for u32 {}
fn hello() -> Box<impl Trait + ?Sized> {
//[next]~^ ERROR: the trait bound `dyn Send: Trait` is not satisfied
if true {
let x = hello();
//[next]~^ ERROR: the trait bound `dyn Send: Trait` is not satisfied
@ -17,7 +16,6 @@ fn hello() -> Box<impl Trait + ?Sized> {
//[old]~^ ERROR: the size for values of type `impl Trait + ?Sized` cannot be know
}
Box::new(1u32)
//[next]~^ ERROR: mismatched types
}
fn main() {}

6
tests/ui/traits/negative-bounds/opaque-type-unsatisfied-bound.rs
View file

@ -14,13 +14,7 @@ fn main() {
fn weird0() -> impl Sized + !Sized {}
//~^ ERROR the trait bound `(): !Sized` is not satisfied
//~| ERROR the trait bound `(): !Sized` is not satisfied
//~| ERROR the trait bound `(): !Sized` is not satisfied
fn weird1() -> impl !Sized + Sized {}
//~^ ERROR the trait bound `(): !Sized` is not satisfied
//~| ERROR the trait bound `(): !Sized` is not satisfied
//~| ERROR the trait bound `(): !Sized` is not satisfied
fn weird2() -> impl !Sized {}
//~^ ERROR the trait bound `(): !Sized` is not satisfied
//~| ERROR the trait bound `(): !Sized` is not satisfied
//~| ERROR the trait bound `(): !Sized` is not satisfied

42
tests/ui/traits/negative-bounds/opaque-type-unsatisfied-bound.stderr
View file

@ -5,53 +5,17 @@ LL | fn weird0() -> impl Sized + !Sized {}
| ^^^^^^^^^^^^^^^^^^^ the trait bound `(): !Sized` is not satisfied
error[E0277]: the trait bound `(): !Sized` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:15:36
|
LL | fn weird0() -> impl Sized + !Sized {}
| ^^ the trait bound `(): !Sized` is not satisfied
error[E0277]: the trait bound `(): !Sized` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:15:1
|
LL | fn weird0() -> impl Sized + !Sized {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait bound `(): !Sized` is not satisfied
error[E0277]: the trait bound `(): !Sized` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:19:16
--> $DIR/opaque-type-unsatisfied-bound.rs:17:16
|
LL | fn weird1() -> impl !Sized + Sized {}
| ^^^^^^^^^^^^^^^^^^^ the trait bound `(): !Sized` is not satisfied
error[E0277]: the trait bound `(): !Sized` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:19:36
|
LL | fn weird1() -> impl !Sized + Sized {}
| ^^ the trait bound `(): !Sized` is not satisfied
error[E0277]: the trait bound `(): !Sized` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:19:1
|
LL | fn weird1() -> impl !Sized + Sized {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait bound `(): !Sized` is not satisfied
error[E0277]: the trait bound `(): !Sized` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:23:16
--> $DIR/opaque-type-unsatisfied-bound.rs:19:16
|
LL | fn weird2() -> impl !Sized {}
| ^^^^^^^^^^^ the trait bound `(): !Sized` is not satisfied
error[E0277]: the trait bound `(): !Sized` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:23:28
|
LL | fn weird2() -> impl !Sized {}
| ^^ the trait bound `(): !Sized` is not satisfied
error[E0277]: the trait bound `(): !Sized` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:23:1
|
LL | fn weird2() -> impl !Sized {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait bound `(): !Sized` is not satisfied
error[E0277]: the trait bound `impl !Trait: Trait` is not satisfied
--> $DIR/opaque-type-unsatisfied-bound.rs:12:13
|
@ -66,6 +30,6 @@ note: required by a bound in `consume`
LL | fn consume(_: impl Trait) {}
| ^^^^^ required by this bound in `consume`
error: aborting due to 10 previous errors
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0277`.

2
tests/ui/traits/negative-bounds/opaque-type-unsatisfied-fn-bound.rs
View file

@ -4,7 +4,5 @@
fn produce() -> impl !Fn<(u32,)> {}
//~^ ERROR the trait bound `(): !Fn(u32)` is not satisfied
//~| ERROR the trait bound `(): !Fn(u32)` is not satisfied
//~| ERROR the trait bound `(): !Fn(u32)` is not satisfied
fn main() {}

14
tests/ui/traits/negative-bounds/opaque-type-unsatisfied-fn-bound.stderr
View file

@ -4,18 +4,6 @@ error[E0277]: the trait bound `(): !Fn(u32)` is not satisfied
LL | fn produce() -> impl !Fn<(u32,)> {}
| ^^^^^^^^^^^^^^^^ the trait bound `(): !Fn(u32)` is not satisfied
error[E0277]: the trait bound `(): !Fn(u32)` is not satisfied
--> $DIR/opaque-type-unsatisfied-fn-bound.rs:5:34
|
LL | fn produce() -> impl !Fn<(u32,)> {}
| ^^ the trait bound `(): !Fn(u32)` is not satisfied
error[E0277]: the trait bound `(): !Fn(u32)` is not satisfied
--> $DIR/opaque-type-unsatisfied-fn-bound.rs:5:1
|
LL | fn produce() -> impl !Fn<(u32,)> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait bound `(): !Fn(u32)` is not satisfied
error: aborting due to 3 previous errors
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0277`.