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Rollup merge of #86011 - tlyu:correct-sized-bound-spans, r=estebank
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move implicit `Sized` predicate to end of list

In `Bounds::predicates()`, move the implicit `Sized` predicate to the
end of the generated list. This means that if there is an explicit
`Sized` bound, it will be checked first, and any resulting
diagnostics will have a more useful span.

Fixes #85998, at least partially. ~~Based on #85979, but only the last 2 commits are new for this pull request.~~ (edit: rebased) A full fix would need to deal with where-clauses, and that seems difficult. Basically, predicates are being collected in multiple stages, and there are two places where implicit `Sized` predicates can be inserted: once for generic parameters, and once for where-clauses. I think this insertion is happening too early, and we should actually do it only at points where we collect all of the relevant trait bounds for a type parameter.

I could use some help interpreting the changes to the stderr output. It looks like reordering the predicates changed some diagnostics that don't obviously have anything to do with `Sized` bounds. Possibly some error reporting code is making assumptions about ordering of predicates? The diagnostics for src/test/ui/derives/derives-span-Hash-*.rs seem to have improved, no longer pointing at the type parameter identifier, but src/test/ui/type-alias-impl-trait/generic_duplicate_param_use9.rs became less verbose for some reason.

I also ran into an instance of #84970 while working on this, but I kind of expected that could happen, because I'm reordering predicates. I can open a separate issue on that if it would be helpful.

``@estebank`` this seems likely to conflict (slightly?) with your work on #85947; how would you like to resolve that?
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matthiaskrgr authored Oct 15, 2021
2 parents e1e9319 + c07f5c4 commit 36a1076
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9 changes: 5 additions & 4 deletions compiler/rustc_typeck/src/bounds.rs
Original file line number Diff line number Diff line change
Expand Up @@ -64,16 +64,16 @@ impl<'tcx> Bounds<'tcx> {
})
});

sized_predicate
.into_iter()
.chain(self.region_bounds.iter().map(|&(region_bound, span)| {
self.region_bounds
.iter()
.map(|&(region_bound, span)| {
(
region_bound
.map_bound(|region_bound| ty::OutlivesPredicate(param_ty, region_bound))
.to_predicate(tcx),
span,
)
}))
})
.chain(self.trait_bounds.iter().map(|&(bound_trait_ref, span, constness)| {
let predicate = bound_trait_ref.with_constness(constness).to_predicate(tcx);
(predicate, span)
Expand All @@ -83,6 +83,7 @@ impl<'tcx> Bounds<'tcx> {
.iter()
.map(|&(projection, span)| (projection.to_predicate(tcx), span)),
)
.chain(sized_predicate.into_iter())
.collect()
}
}
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ note: required by a bound in `std::hash::Hash::hash`
--> $SRC_DIR/core/src/hash/mod.rs:LL:COL
|
LL | fn hash<H: Hasher>(&self, state: &mut H);
| ^ required by this bound in `std::hash::Hash::hash`
| ^^^^^^ required by this bound in `std::hash::Hash::hash`
= note: this error originates in the derive macro `Hash` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error
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2 changes: 1 addition & 1 deletion src/test/ui/derives/derives-span-Hash-enum.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ note: required by a bound in `std::hash::Hash::hash`
--> $SRC_DIR/core/src/hash/mod.rs:LL:COL
|
LL | fn hash<H: Hasher>(&self, state: &mut H);
| ^ required by this bound in `std::hash::Hash::hash`
| ^^^^^^ required by this bound in `std::hash::Hash::hash`
= note: this error originates in the derive macro `Hash` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error
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2 changes: 1 addition & 1 deletion src/test/ui/derives/derives-span-Hash-struct.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ note: required by a bound in `std::hash::Hash::hash`
--> $SRC_DIR/core/src/hash/mod.rs:LL:COL
|
LL | fn hash<H: Hasher>(&self, state: &mut H);
| ^ required by this bound in `std::hash::Hash::hash`
| ^^^^^^ required by this bound in `std::hash::Hash::hash`
= note: this error originates in the derive macro `Hash` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error
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2 changes: 1 addition & 1 deletion src/test/ui/derives/derives-span-Hash-tuple-struct.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ note: required by a bound in `std::hash::Hash::hash`
--> $SRC_DIR/core/src/hash/mod.rs:LL:COL
|
LL | fn hash<H: Hasher>(&self, state: &mut H);
| ^ required by this bound in `std::hash::Hash::hash`
| ^^^^^^ required by this bound in `std::hash::Hash::hash`
= note: this error originates in the derive macro `Hash` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error
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24 changes: 12 additions & 12 deletions src/test/ui/generic-associated-types/issue-74816.stderr
Original file line number Diff line number Diff line change
@@ -1,34 +1,34 @@
error[E0277]: the trait bound `Self: Trait1` is not satisfied
error[E0277]: the size for values of type `Self` cannot be known at compilation time
--> $DIR/issue-74816.rs:9:5
|
LL | type Associated: Trait1 = Self;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait1` is not implemented for `Self`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
|
note: required by a bound in `Trait2::Associated`
--> $DIR/issue-74816.rs:9:22
--> $DIR/issue-74816.rs:9:5
|
LL | type Associated: Trait1 = Self;
| ^^^^^^ required by this bound in `Trait2::Associated`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Trait2::Associated`
help: consider further restricting `Self`
|
LL | trait Trait2: Trait1 {
| ++++++++
LL | trait Trait2: Sized {
| +++++++

error[E0277]: the size for values of type `Self` cannot be known at compilation time
error[E0277]: the trait bound `Self: Trait1` is not satisfied
--> $DIR/issue-74816.rs:9:5
|
LL | type Associated: Trait1 = Self;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait1` is not implemented for `Self`
|
note: required by a bound in `Trait2::Associated`
--> $DIR/issue-74816.rs:9:5
--> $DIR/issue-74816.rs:9:22
|
LL | type Associated: Trait1 = Self;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Trait2::Associated`
| ^^^^^^ required by this bound in `Trait2::Associated`
help: consider further restricting `Self`
|
LL | trait Trait2: Sized {
| +++++++
LL | trait Trait2: Trait1 {
| ++++++++

error: aborting due to 2 previous errors

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4 changes: 2 additions & 2 deletions src/test/ui/generic-associated-types/issue-86483.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -20,13 +20,13 @@ LL | for<'a> T: 'a,
| ^^

error[E0311]: the parameter type `T` may not live long enough
--> $DIR/issue-86483.rs:9:5
--> $DIR/issue-86483.rs:9:19
|
LL | pub trait IceIce<T>
| - help: consider adding an explicit lifetime bound...: `T: 'a`
...
LL | type Ice<'v>: IntoIterator<Item = &'v T>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds...
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds...
|
note: ...that is required by this bound
--> $DIR/issue-86483.rs:7:16
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Original file line number Diff line number Diff line change
Expand Up @@ -6,10 +6,10 @@ LL | impl Tsized for () {}
|
= help: the trait `Sized` is not implemented for `[()]`
note: required by a bound in `Tsized`
--> $DIR/issue-61631-default-type-param-can-reference-self-in-trait.rs:17:14
--> $DIR/issue-61631-default-type-param-can-reference-self-in-trait.rs:17:17
|
LL | trait Tsized<P: Sized = [Self]> {}
| ^ required by this bound in `Tsized`
| ^^^^^ required by this bound in `Tsized`

error: aborting due to previous error

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14 changes: 12 additions & 2 deletions src/test/ui/issues/issue-16966.stderr
Original file line number Diff line number Diff line change
@@ -1,11 +1,21 @@
error[E0282]: type annotations needed
error[E0283]: type annotations needed
--> $DIR/issue-16966.rs:2:5
|
LL | panic!(std::default::Default::default());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `M` declared on the function `begin_panic`
|
= note: cannot satisfy `_: Any`
note: required by a bound in `begin_panic`
--> $SRC_DIR/std/src/panicking.rs:LL:COL
|
LL | pub fn begin_panic<M: Any + Send>(msg: M) -> ! {
| ^^^ required by this bound in `begin_panic`
= note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider specifying the type argument in the function call
|
LL | $crate::rt::begin_panic::<M>($msg)
| +++++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0282`.
For more information about this error, try `rustc --explain E0283`.
2 changes: 1 addition & 1 deletion src/test/ui/issues/issue-21160.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@ note: required by a bound in `std::hash::Hash::hash`
--> $SRC_DIR/core/src/hash/mod.rs:LL:COL
|
LL | fn hash<H: Hasher>(&self, state: &mut H);
| ^ required by this bound in `std::hash::Hash::hash`
| ^^^^^^ required by this bound in `std::hash::Hash::hash`
= note: this error originates in the derive macro `Hash` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error
Expand Down
2 changes: 1 addition & 1 deletion src/test/ui/issues/issue-23122-2.stderr
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
error[E0275]: overflow evaluating the requirement `<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<T as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next: Sized`
error[E0275]: overflow evaluating the requirement `<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<T as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next: Next`
--> $DIR/issue-23122-2.rs:9:17
|
LL | type Next = <GetNext<T::Next> as Next>::Next;
Expand Down
4 changes: 2 additions & 2 deletions src/test/ui/issues/issue-54954.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -12,10 +12,10 @@ LL | const ARR_LEN: usize = Tt::const_val::<[i8; 123]>();
|
= note: cannot satisfy `_: Tt`
note: required by a bound in `Tt::const_val`
--> $DIR/issue-54954.rs:5:24
--> $DIR/issue-54954.rs:5:27
|
LL | const fn const_val<T: Sized>() -> usize {
| ^ required by this bound in `Tt::const_val`
| ^^^^^ required by this bound in `Tt::const_val`

error: aborting due to 2 previous errors

Expand Down
12 changes: 6 additions & 6 deletions src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -20,11 +20,11 @@ error[E0277]: the trait bound `T: Bar` is not satisfied
LL | T::c::<T>();
| ^^^^^^^^^ the trait `Bar` is not implemented for `T`
|
note: required by `Foo::c`
--> $DIR/trait-where-clause.rs:9:5
note: required by a bound in `Foo::c`
--> $DIR/trait-where-clause.rs:9:10
|
LL | fn c<T: ~const Bar>();
| ^^^^^^^^^^^^^^^^^^^^^^
| ^ required by this bound in `Foo::c`
help: consider further restricting this bound
|
LL | const fn test1<T: ~const Foo + Bar + Bar>() {
Expand Down Expand Up @@ -52,11 +52,11 @@ error[E0277]: the trait bound `T: Bar` is not satisfied
LL | T::c::<T>();
| ^^^^^^^^^ the trait `Bar` is not implemented for `T`
|
note: required by `Foo::c`
--> $DIR/trait-where-clause.rs:9:5
note: required by a bound in `Foo::c`
--> $DIR/trait-where-clause.rs:9:10
|
LL | fn c<T: ~const Bar>();
| ^^^^^^^^^^^^^^^^^^^^^^
| ^ required by this bound in `Foo::c`
help: consider further restricting this bound
|
LL | fn test3<T: Foo + Bar>() {
Expand Down
4 changes: 2 additions & 2 deletions src/test/ui/suggestions/issue-84973-blacklist.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -49,10 +49,10 @@ LL | f_sized(*ref_cl);
|
= help: the trait `Sized` is not implemented for `dyn Fn()`
note: required by a bound in `f_sized`
--> $DIR/issue-84973-blacklist.rs:9:12
--> $DIR/issue-84973-blacklist.rs:9:15
|
LL | fn f_sized<T: Sized>(t: T) {}
| ^ required by this bound in `f_sized`
| ^^^^^ required by this bound in `f_sized`

error[E0277]: `Rc<{integer}>` cannot be sent between threads safely
--> $DIR/issue-84973-blacklist.rs:27:12
Expand Down
8 changes: 4 additions & 4 deletions src/test/ui/suggestions/slice-issue-87994.stderr
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
error[E0277]: the size for values of type `[i32]` cannot be known at compilation time
error[E0277]: `[i32]` is not an iterator
--> $DIR/slice-issue-87994.rs:3:12
|
LL | for _ in v[1..] {
Expand All @@ -18,7 +18,7 @@ LL | for _ in &v[1..] {
LL | for _ in &mut v[1..] {
| ++++

error[E0277]: `[i32]` is not an iterator
error[E0277]: the size for values of type `[i32]` cannot be known at compilation time
--> $DIR/slice-issue-87994.rs:3:12
|
LL | for _ in v[1..] {
Expand All @@ -38,7 +38,7 @@ LL | for _ in &v[1..] {
LL | for _ in &mut v[1..] {
| ++++

error[E0277]: the size for values of type `[K]` cannot be known at compilation time
error[E0277]: `[K]` is not an iterator
--> $DIR/slice-issue-87994.rs:11:13
|
LL | for i2 in v2[1..] {
Expand All @@ -58,7 +58,7 @@ LL | for i2 in &v2[1..] {
LL | for i2 in &mut v2[1..] {
| ++++

error[E0277]: `[K]` is not an iterator
error[E0277]: the size for values of type `[K]` cannot be known at compilation time
--> $DIR/slice-issue-87994.rs:11:13
|
LL | for i2 in v2[1..] {
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ use std::fmt::Debug;
fn main() {}

type Two<A, B> = impl Debug;
//~^ ERROR the trait bound `A: Foo` is not satisfied in `(A, B, <A as Foo>::Bar)`
//~^ ERROR the trait bound `A: Foo` is not satisfied
//~| ERROR `A` doesn't implement `Debug`
//~| ERROR `B` doesn't implement `Debug`

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -10,18 +10,6 @@ note: previous use here
LL | fn two<T: Debug + Foo, U: Debug>(t: T, u: U) -> Two<T, U> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0277]: the trait bound `A: Foo` is not satisfied in `(A, B, <A as Foo>::Bar)`
--> $DIR/generic_duplicate_param_use9.rs:7:18
|
LL | type Two<A, B> = impl Debug;
| ^^^^^^^^^^ within `(A, B, <A as Foo>::Bar)`, the trait `Foo` is not implemented for `A`
|
= note: required because it appears within the type `(A, B, <A as Foo>::Bar)`
help: consider restricting type parameter `A`
|
LL | type Two<A: Foo, B> = impl Debug;
| +++++

error[E0277]: `A` doesn't implement `Debug`
--> $DIR/generic_duplicate_param_use9.rs:7:18
|
Expand All @@ -46,6 +34,18 @@ help: consider restricting type parameter `B`
LL | type Two<A, B: std::fmt::Debug> = impl Debug;
| +++++++++++++++++

error[E0277]: the trait bound `A: Foo` is not satisfied
--> $DIR/generic_duplicate_param_use9.rs:7:18
|
LL | type Two<A, B> = impl Debug;
| ^^^^^^^^^^ the trait `Foo` is not implemented for `A`
|
= note: required because of the requirements on the impl of `Debug` for `(A, B, <A as Foo>::Bar)`
help: consider restricting type parameter `A`
|
LL | type Two<A: Foo, B> = impl Debug;
| +++++

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0277`.
4 changes: 2 additions & 2 deletions src/test/ui/unique-object-noncopyable.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -19,10 +19,10 @@ LL | | >(Unique<T>, A);
| |________________- doesn't satisfy `Box<dyn Foo>: Clone`
|
= note: the following trait bounds were not satisfied:
`dyn Foo: Sized`
which is required by `Box<dyn Foo>: Clone`
`dyn Foo: Clone`
which is required by `Box<dyn Foo>: Clone`
`dyn Foo: Sized`
which is required by `Box<dyn Foo>: Clone`

error: aborting due to previous error

Expand Down
4 changes: 2 additions & 2 deletions src/test/ui/unsized/unsized-bare-typaram.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -7,10 +7,10 @@ LL | fn foo<T: ?Sized>() { bar::<T>() }
| this type parameter needs to be `std::marker::Sized`
|
note: required by a bound in `bar`
--> $DIR/unsized-bare-typaram.rs:1:8
--> $DIR/unsized-bare-typaram.rs:1:11
|
LL | fn bar<T: Sized>() { }
| ^ required by this bound in `bar`
| ^^^^^ required by this bound in `bar`
help: consider removing the `?Sized` bound to make the type parameter `Sized`
|
LL - fn foo<T: ?Sized>() { bar::<T>() }
Expand Down
4 changes: 2 additions & 2 deletions src/test/ui/unsized/unsized-struct.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -38,10 +38,10 @@ note: required because it appears within the type `Bar<T>`
LL | struct Bar<T: ?Sized> { data: T }
| ^^^
note: required by a bound in `is_sized`
--> $DIR/unsized-struct.rs:1:13
--> $DIR/unsized-struct.rs:1:15
|
LL | fn is_sized<T:Sized>() { }
| ^ required by this bound in `is_sized`
| ^^^^^ required by this bound in `is_sized`
help: consider removing the `?Sized` bound to make the type parameter `Sized`
|
LL - fn bar2<T: ?Sized>() { is_sized::<Bar<T>>() }
Expand Down

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