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add a test for pointer casts involving un/re/wrapping trait objects

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the errors should not be there, this is a bug/missing feature.
This commit is contained in:
Waffle Lapkin 2025-01-16 16:12:27 +01:00
parent cdd8af2299
commit 5712d2e956
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40
tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.rs Normal file
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// Combination of `ptr-to-trait-obj-wrap.rs` and `ptr-to-trait-obj-add-auto.rs`.
//
// Checks that you *can't* add auto traits to trait object in pointer casts involving wrapping said
// traits structures.
trait A {}
struct W<T: ?Sized>(T);
struct X<T: ?Sized>(T);
fn unwrap(a: *const W<dyn A>) -> *const (dyn A + Send) {
a as _
//~^ error
//~| error
//~| error
}
fn unwrap_nested(a: *const W<W<dyn A>>) -> *const W<dyn A + Send> {
a as _
//~^ error
//~| error
//~| error
}
fn rewrap(a: *const W<dyn A>) -> *const X<dyn A + Send> {
a as _
//~^ error: cannot add auto trait `Send` to dyn bound via pointer cast
}
fn rewrap_nested(a: *const W<W<dyn A>>) -> *const W<X<dyn A + Send>> {
a as _
//~^ error: cannot add auto trait `Send` to dyn bound via pointer cast
}
fn wrap(a: *const dyn A) -> *const W<dyn A + Send> {
a as _
//~^ error: cannot add auto trait `Send` to dyn bound via pointer cast
}
fn main() {}

113
tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.stderr Normal file
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error[E0277]: the trait bound `W<(dyn A + 'static)>: A` is not satisfied
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:12:5
|
LL | a as _
| ^ the trait `A` is not implemented for `W<(dyn A + 'static)>`
|
help: this trait has no implementations, consider adding one
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:6:1
|
LL | trait A {}
| ^^^^^^^
= note: required for the cast from `*const W<(dyn A + 'static)>` to `*const dyn A + Send`
error[E0277]: `(dyn A + 'static)` cannot be sent between threads safely
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:12:5
|
LL | a as _
| ^ `(dyn A + 'static)` cannot be sent between threads safely
|
= help: within `W<(dyn A + 'static)>`, the trait `Send` is not implemented for `(dyn A + 'static)`
note: required because it appears within the type `W<(dyn A + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:8:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<(dyn A + 'static)>` to `*const dyn A + Send`
error[E0277]: the size for values of type `(dyn A + 'static)` cannot be known at compilation time
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:12:5
|
LL | a as _
| ^ doesn't have a size known at compile-time
|
= help: within `W<(dyn A + 'static)>`, the trait `Sized` is not implemented for `(dyn A + 'static)`
note: required because it appears within the type `W<(dyn A + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:8:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<(dyn A + 'static)>` to `*const dyn A + Send`
error[E0277]: the trait bound `W<(dyn A + 'static)>: A` is not satisfied
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:19:5
|
LL | a as _
| ^ the trait `A` is not implemented for `W<(dyn A + 'static)>`
|
help: this trait has no implementations, consider adding one
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:6:1
|
LL | trait A {}
| ^^^^^^^
= note: required for the cast from `*const W<W<(dyn A + 'static)>>` to `*const W<dyn A + Send>`
error[E0277]: `(dyn A + 'static)` cannot be sent between threads safely
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:19:5
|
LL | a as _
| ^ `(dyn A + 'static)` cannot be sent between threads safely
|
= help: within `W<(dyn A + 'static)>`, the trait `Send` is not implemented for `(dyn A + 'static)`
note: required because it appears within the type `W<(dyn A + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:8:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<W<(dyn A + 'static)>>` to `*const W<dyn A + Send>`
error[E0277]: the size for values of type `(dyn A + 'static)` cannot be known at compilation time
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:19:5
|
LL | a as _
| ^ doesn't have a size known at compile-time
|
= help: within `W<(dyn A + 'static)>`, the trait `Sized` is not implemented for `(dyn A + 'static)`
note: required because it appears within the type `W<(dyn A + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:8:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<W<(dyn A + 'static)>>` to `*const W<dyn A + Send>`
error[E0804]: cannot add auto trait `Send` to dyn bound via pointer cast
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:26:5
|
LL | a as _
| ^^^^^^ unsupported cast
|
= note: this could allow UB elsewhere
= help: use `transmute` if you're sure this is sound
error[E0804]: cannot add auto trait `Send` to dyn bound via pointer cast
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:31:5
|
LL | a as _
| ^^^^^^ unsupported cast
|
= note: this could allow UB elsewhere
= help: use `transmute` if you're sure this is sound
error[E0804]: cannot add auto trait `Send` to dyn bound via pointer cast
--> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:36:5
|
LL | a as _
| ^^^^^^ unsupported cast
|
= note: this could allow UB elsewhere
= help: use `transmute` if you're sure this is sound
error: aborting due to 9 previous errors
Some errors have detailed explanations: E0277, E0804.
For more information about an error, try `rustc --explain E0277`.

38
tests/ui/cast/ptr-to-trait-obj-wrap-different-args.rs Normal file
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// Combination of `ptr-to-trait-obj-different-args.rs` and `ptr-to-trait-obj-wrap.rs`.
//
// Checks that you *can't* change type arguments of trait objects in pointer casts involving
// wrapping said traits structures.
trait A<T> {}
struct W<T: ?Sized>(T);
struct X<T: ?Sized>(T);
fn unwrap<F, G>(a: *const W<dyn A<F>>) -> *const dyn A<G> {
a as _
//~^ error
//~| error
}
fn unwrap_nested<F, G>(a: *const W<W<dyn A<F>>>) -> *const W<dyn A<G>> {
a as _
//~^ error
//~| error
}
fn rewrap<F, G>(a: *const W<dyn A<F>>) -> *const X<dyn A<G>> {
a as _
//~^ error: casting `*const W<(dyn A<F> + 'static)>` as `*const X<dyn A<G>>` is invalid
}
fn rewrap_nested<F, G>(a: *const W<W<dyn A<F>>>) -> *const W<X<dyn A<G>>> {
a as _
//~^ error: casting `*const W<W<(dyn A<F> + 'static)>>` as `*const W<X<dyn A<G>>>` is invalid
}
fn wrap<F, G>(a: *const dyn A<F>) -> *const W<dyn A<G>> {
a as _
//~^ error: casting `*const (dyn A<F> + 'static)` as `*const W<dyn A<G>>` is invalid
}
fn main() {}

82
tests/ui/cast/ptr-to-trait-obj-wrap-different-args.stderr Normal file
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error[E0277]: the trait bound `W<(dyn A<F> + 'static)>: A<G>` is not satisfied
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:12:5
|
LL | a as _
| ^ the trait `A<G>` is not implemented for `W<(dyn A<F> + 'static)>`
|
help: this trait has no implementations, consider adding one
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:6:1
|
LL | trait A<T> {}
| ^^^^^^^^^^
= note: required for the cast from `*const W<(dyn A<F> + 'static)>` to `*const dyn A<G>`
error[E0277]: the size for values of type `(dyn A<F> + 'static)` cannot be known at compilation time
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:12:5
|
LL | a as _
| ^ doesn't have a size known at compile-time
|
= help: within `W<(dyn A<F> + 'static)>`, the trait `Sized` is not implemented for `(dyn A<F> + 'static)`
note: required because it appears within the type `W<(dyn A<F> + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:8:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<(dyn A<F> + 'static)>` to `*const dyn A<G>`
error[E0277]: the trait bound `W<(dyn A<F> + 'static)>: A<G>` is not satisfied
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:18:5
|
LL | a as _
| ^ the trait `A<G>` is not implemented for `W<(dyn A<F> + 'static)>`
|
help: this trait has no implementations, consider adding one
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:6:1
|
LL | trait A<T> {}
| ^^^^^^^^^^
= note: required for the cast from `*const W<W<(dyn A<F> + 'static)>>` to `*const W<dyn A<G>>`
error[E0277]: the size for values of type `(dyn A<F> + 'static)` cannot be known at compilation time
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:18:5
|
LL | a as _
| ^ doesn't have a size known at compile-time
|
= help: within `W<(dyn A<F> + 'static)>`, the trait `Sized` is not implemented for `(dyn A<F> + 'static)`
note: required because it appears within the type `W<(dyn A<F> + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:8:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<W<(dyn A<F> + 'static)>>` to `*const W<dyn A<G>>`
error[E0606]: casting `*const W<(dyn A<F> + 'static)>` as `*const X<dyn A<G>>` is invalid
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:24:5
|
LL | a as _
| ^^^^^^
|
= note: the trait objects may have different vtables
error[E0606]: casting `*const W<W<(dyn A<F> + 'static)>>` as `*const W<X<dyn A<G>>>` is invalid
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:29:5
|
LL | a as _
| ^^^^^^
|
= note: the trait objects may have different vtables
error[E0606]: casting `*const (dyn A<F> + 'static)` as `*const W<dyn A<G>>` is invalid
--> $DIR/ptr-to-trait-obj-wrap-different-args.rs:34:5
|
LL | a as _
| ^^^^^^
|
= note: the trait objects may have different vtables
error: aborting due to 7 previous errors
Some errors have detailed explanations: E0277, E0606.
For more information about an error, try `rustc --explain E0277`.

41
tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.rs Normal file
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// Combination of `ptr-to-trait-obj-different-regions-misc.rs` and `ptr-to-trait-obj-wrap.rs`.
//
// Checks that you *can't* change lifetime arguments of trait objects in pointer casts involving
// wrapping said traits structures.
trait A<'a> {}
struct W<T: ?Sized>(T);
struct X<T: ?Sized>(T);
fn unwrap<'a, 'b>(a: *const W<dyn A<'a>>) -> *const dyn A<'b> {
a as _
//~^ error
//~| error
}
fn unwrap_nested<'a, 'b>(a: *const W<W<dyn A<'a>>>) -> *const W<dyn A<'b>> {
a as _
//~^ error
//~| error
}
fn rewrap<'a, 'b>(a: *const W<dyn A<'a>>) -> *const X<dyn A<'b>> {
a as _
//~^ error: lifetime may not live long enough
//~| error: lifetime may not live long enough
}
fn rewrap_nested<'a, 'b>(a: *const W<W<dyn A<'a>>>) -> *const W<X<dyn A<'b>>> {
a as _
//~^ error: lifetime may not live long enough
//~| error: lifetime may not live long enough
}
fn wrap<'a, 'b>(a: *const dyn A<'a>) -> *const W<dyn A<'b>> {
a as _
//~^ error: lifetime may not live long enough
//~| error: lifetime may not live long enough
}
fn main() {}

139
tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.stderr Normal file
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error[E0277]: the trait bound `W<(dyn A<'a> + 'static)>: A<'b>` is not satisfied
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:12:5
|
LL | a as _
| ^ the trait `A<'b>` is not implemented for `W<(dyn A<'a> + 'static)>`
|
help: this trait has no implementations, consider adding one
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:6:1
|
LL | trait A<'a> {}
| ^^^^^^^^^^^
= note: required for the cast from `*const W<(dyn A<'a> + 'static)>` to `*const dyn A<'b>`
error[E0277]: the size for values of type `(dyn A<'a> + 'static)` cannot be known at compilation time
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:12:5
|
LL | a as _
| ^ doesn't have a size known at compile-time
|
= help: within `W<(dyn A<'a> + 'static)>`, the trait `Sized` is not implemented for `(dyn A<'a> + 'static)`
note: required because it appears within the type `W<(dyn A<'a> + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:8:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<(dyn A<'a> + 'static)>` to `*const dyn A<'b>`
error[E0277]: the trait bound `W<(dyn A<'a> + 'static)>: A<'b>` is not satisfied
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:18:5
|
LL | a as _
| ^ the trait `A<'b>` is not implemented for `W<(dyn A<'a> + 'static)>`
|
help: this trait has no implementations, consider adding one
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:6:1
|
LL | trait A<'a> {}
| ^^^^^^^^^^^
= note: required for the cast from `*const W<W<(dyn A<'a> + 'static)>>` to `*const W<dyn A<'b>>`
error[E0277]: the size for values of type `(dyn A<'a> + 'static)` cannot be known at compilation time
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:18:5
|
LL | a as _
| ^ doesn't have a size known at compile-time
|
= help: within `W<(dyn A<'a> + 'static)>`, the trait `Sized` is not implemented for `(dyn A<'a> + 'static)`
note: required because it appears within the type `W<(dyn A<'a> + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:8:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<W<(dyn A<'a> + 'static)>>` to `*const W<dyn A<'b>>`
error: lifetime may not live long enough
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:24:5
|
LL | fn rewrap<'a, 'b>(a: *const W<dyn A<'a>>) -> *const X<dyn A<'b>> {
| -- -- lifetime `'b` defined here
| |
| lifetime `'a` defined here
LL | a as _
| ^^^^^^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b`
|
= help: consider adding the following bound: `'b: 'a`
error: lifetime may not live long enough
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:24:5
|
LL | fn rewrap<'a, 'b>(a: *const W<dyn A<'a>>) -> *const X<dyn A<'b>> {
| -- -- lifetime `'b` defined here
| |
| lifetime `'a` defined here
LL | a as _
| ^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a`
|
= help: consider adding the following bound: `'a: 'b`
help: `'b` and `'a` must be the same: replace one with the other
error: lifetime may not live long enough
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:30:5
|
LL | fn rewrap_nested<'a, 'b>(a: *const W<W<dyn A<'a>>>) -> *const W<X<dyn A<'b>>> {
| -- -- lifetime `'b` defined here
| |
| lifetime `'a` defined here
LL | a as _
| ^^^^^^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b`
|
= help: consider adding the following bound: `'b: 'a`
error: lifetime may not live long enough
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:30:5
|
LL | fn rewrap_nested<'a, 'b>(a: *const W<W<dyn A<'a>>>) -> *const W<X<dyn A<'b>>> {
| -- -- lifetime `'b` defined here
| |
| lifetime `'a` defined here
LL | a as _
| ^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a`
|
= help: consider adding the following bound: `'a: 'b`
help: `'b` and `'a` must be the same: replace one with the other
|
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
error: lifetime may not live long enough
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:36:5
|
LL | fn wrap<'a, 'b>(a: *const dyn A<'a>) -> *const W<dyn A<'b>> {
| -- -- lifetime `'b` defined here
| |
| lifetime `'a` defined here
LL | a as _
| ^^^^^^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b`
|
= help: consider adding the following bound: `'b: 'a`
error: lifetime may not live long enough
--> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:36:5
|
LL | fn wrap<'a, 'b>(a: *const dyn A<'a>) -> *const W<dyn A<'b>> {
| -- -- lifetime `'b` defined here
| |
| lifetime `'a` defined here
LL | a as _
| ^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a`
|
= help: consider adding the following bound: `'a: 'b`
help: `'b` and `'a` must be the same: replace one with the other
|
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
error: aborting due to 10 previous errors
For more information about this error, try `rustc --explain E0277`.

36
tests/ui/cast/ptr-to-trait-obj-wrap.rs Normal file
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// Checks that various casts of pointers to trait objects wrapped in structures
// work. Note that the metadata doesn't change when a DST is wrapped in a
// structure, so these casts *are* fine.
//
// `unwrap` and `unwrap_nested` currently don't work due to a compiler limitation.
trait A {}
struct W<T: ?Sized>(T);
struct X<T: ?Sized>(T);
fn unwrap(a: *const W<dyn A>) -> *const dyn A {
a as _
//~^ error
//~| error
}
fn unwrap_nested(a: *const W<W<dyn A>>) -> *const W<dyn A> {
a as _
//~^ error
//~| error
}
fn rewrap(a: *const W<dyn A>) -> *const X<dyn A> {
a as _
}
fn rewrap_nested(a: *const W<W<dyn A>>) -> *const W<X<dyn A>> {
a as _
}
fn wrap(a: *const dyn A) -> *const W<dyn A> {
a as _
}
fn main() {}

57
tests/ui/cast/ptr-to-trait-obj-wrap.stderr Normal file
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error[E0277]: the trait bound `W<(dyn A + 'static)>: A` is not satisfied
--> $DIR/ptr-to-trait-obj-wrap.rs:13:5
|
LL | a as _
| ^ the trait `A` is not implemented for `W<(dyn A + 'static)>`
|
help: this trait has no implementations, consider adding one
--> $DIR/ptr-to-trait-obj-wrap.rs:7:1
|
LL | trait A {}
| ^^^^^^^
= note: required for the cast from `*const W<(dyn A + 'static)>` to `*const dyn A`
error[E0277]: the size for values of type `(dyn A + 'static)` cannot be known at compilation time
--> $DIR/ptr-to-trait-obj-wrap.rs:13:5
|
LL | a as _
| ^ doesn't have a size known at compile-time
|
= help: within `W<(dyn A + 'static)>`, the trait `Sized` is not implemented for `(dyn A + 'static)`
note: required because it appears within the type `W<(dyn A + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap.rs:9:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<(dyn A + 'static)>` to `*const dyn A`
error[E0277]: the trait bound `W<(dyn A + 'static)>: A` is not satisfied
--> $DIR/ptr-to-trait-obj-wrap.rs:19:5
|
LL | a as _
| ^ the trait `A` is not implemented for `W<(dyn A + 'static)>`
|
help: this trait has no implementations, consider adding one
--> $DIR/ptr-to-trait-obj-wrap.rs:7:1
|
LL | trait A {}
| ^^^^^^^
= note: required for the cast from `*const W<W<(dyn A + 'static)>>` to `*const W<dyn A>`
error[E0277]: the size for values of type `(dyn A + 'static)` cannot be known at compilation time
--> $DIR/ptr-to-trait-obj-wrap.rs:19:5
|
LL | a as _
| ^ doesn't have a size known at compile-time
|
= help: within `W<(dyn A + 'static)>`, the trait `Sized` is not implemented for `(dyn A + 'static)`
note: required because it appears within the type `W<(dyn A + 'static)>`
--> $DIR/ptr-to-trait-obj-wrap.rs:9:8
|
LL | struct W<T: ?Sized>(T);
| ^
= note: required for the cast from `*const W<W<(dyn A + 'static)>>` to `*const W<dyn A>`
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0277`.