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Rollup merge of #133394 - compiler-errors:dyn-more-errors, r=lcnr

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Bail on more errors in dyn ty lowering

If we have more than one principal trait, or if we have a principal trait with errors in it, then bail with `TyKind::Error` rather than attempting lowering. Lowering a dyn trait with more than one principal just arbitrarily chooses the first one and drops the subsequent ones, and lowering a dyn trait path with errors in it is just kinda useless.

This suppresses unnecessary errors which I think is net-good, but also is important to make sure that we don't end up leaking `{type error}` in https://github.com/rust-lang/rust/issues/133388 error messaging :)

r? types
This commit is contained in:
Michael Goulet 2024-11-26 12:03:44 -05:00 • committed by GitHub
commit b0ed5ac730
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22 changed files with 63 additions and 457 deletions
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20
compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs
View file

@ -8,7 +8,8 @@ use rustc_lint_defs::builtin::UNUSED_ASSOCIATED_TYPE_BOUNDS;
use rustc_middle::span_bug; use rustc_middle::span_bug;
use rustc_middle::ty::fold::BottomUpFolder; use rustc_middle::ty::fold::BottomUpFolder;
use rustc_middle::ty::{ use rustc_middle::ty::{
self, DynKind, ExistentialPredicateStableCmpExt as _, Ty, TyCtxt, TypeFoldable, Upcast, self, DynKind, ExistentialPredicateStableCmpExt as _, Ty, TyCtxt, TypeFoldable,
TypeVisitableExt, Upcast,
}; };
use rustc_span::{ErrorGuaranteed, Span}; use rustc_span::{ErrorGuaranteed, Span};
use rustc_trait_selection::error_reporting::traits::report_dyn_incompatibility; use rustc_trait_selection::error_reporting::traits::report_dyn_incompatibility;
@ -92,11 +93,20 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
let (mut auto_traits, regular_traits): (Vec<_>, Vec<_>) = let (mut auto_traits, regular_traits): (Vec<_>, Vec<_>) =
expanded_traits.partition(|i| tcx.trait_is_auto(i.trait_ref().def_id())); expanded_traits.partition(|i| tcx.trait_is_auto(i.trait_ref().def_id()));
// We don't support >1 principal
if regular_traits.len() > 1 { if regular_traits.len() > 1 {
let _ = self.report_trait_object_addition_traits_error(&regular_traits); let guar = self.report_trait_object_addition_traits_error(&regular_traits);
} else if regular_traits.is_empty() && auto_traits.is_empty() { return Ty::new_error(tcx, guar);
let reported = self.report_trait_object_with_no_traits_error(span, &trait_bounds); }
return Ty::new_error(tcx, reported); // We don't support empty trait objects.
if regular_traits.is_empty() && auto_traits.is_empty() {
let guar = self.report_trait_object_with_no_traits_error(span, &trait_bounds);
return Ty::new_error(tcx, guar);
}
// Don't create a dyn trait if we have errors in the principal.
if let Err(guar) = trait_bounds.error_reported() {
return Ty::new_error(tcx, guar);
} }
// Check that there are no gross dyn-compatibility violations; // Check that there are no gross dyn-compatibility violations;

2
tests/crashes/130521.rs
View file

@ -1,7 +1,7 @@
//@ known-bug: #130521 //@ known-bug: #130521
#![feature(dyn_compatible_for_dispatch)] #![feature(dyn_compatible_for_dispatch)]
struct Vtable(dyn Cap); struct Vtable(dyn Cap<'static>);
trait Cap<'a> {} trait Cap<'a> {}

1
tests/rustdoc-ui/unable-fulfill-trait.rs
View file

@ -3,7 +3,6 @@
pub struct Foo<'a, 'b, T> { pub struct Foo<'a, 'b, T> {
field1: dyn Bar<'a, 'b>, field1: dyn Bar<'a, 'b>,
//~^ ERROR //~^ ERROR
//~| ERROR
} }
pub trait Bar<'x, 's, U> pub trait Bar<'x, 's, U>

13
tests/rustdoc-ui/unable-fulfill-trait.stderr
View file

@ -5,7 +5,7 @@ LL | field1: dyn Bar<'a, 'b>,
| ^^^ expected 1 generic argument | ^^^ expected 1 generic argument
| |
note: trait defined here, with 1 generic parameter: `U` note: trait defined here, with 1 generic parameter: `U`
--> $DIR/unable-fulfill-trait.rs:9:11 --> $DIR/unable-fulfill-trait.rs:8:11
| |
LL | pub trait Bar<'x, 's, U> LL | pub trait Bar<'x, 's, U>
| ^^^ - | ^^^ -
@ -14,13 +14,6 @@ help: add missing generic argument
LL | field1: dyn Bar<'a, 'b, U>, LL | field1: dyn Bar<'a, 'b, U>,
| +++ | +++
error[E0227]: ambiguous lifetime bound, explicit lifetime bound required error: aborting due to 1 previous error
--> $DIR/unable-fulfill-trait.rs:4:13
|
LL | field1: dyn Bar<'a, 'b>,
| ^^^^^^^^^^^^^^^
error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0107`.
Some errors have detailed explanations: E0107, E0227.
For more information about an error, try `rustc --explain E0107`.

5
tests/ui/associated-types/issue-22560.rs
View file

@ -7,9 +7,6 @@ trait Sub<Rhs=Self> {
} }
type Test = dyn Add + Sub; type Test = dyn Add + Sub;
//~^ ERROR E0393 //~^ ERROR E0225
//~| ERROR E0191
//~| ERROR E0393
//~| ERROR E0225
fn main() { } fn main() { }

54
tests/ui/associated-types/issue-22560.stderr
View file

@ -9,56 +9,6 @@ LL | type Test = dyn Add + Sub;
= help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add + Sub {}` = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add + Sub {}`
= note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
error[E0191]: the value of the associated types `Output` in `Add`, `Output` in `Sub` must be specified error: aborting due to 1 previous error
--> $DIR/issue-22560.rs:9:17
|
LL | type Output;
| ----------- `Output` defined here
...
LL | type Output;
| ----------- `Output` defined here
...
LL | type Test = dyn Add + Sub;
| ^^^ ^^^ associated type `Output` must be specified
| |
| associated type `Output` must be specified
|
help: specify the associated types
|
LL | type Test = dyn Add<Output = Type> + Sub<Output = Type>;
| ~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~
error[E0393]: the type parameter `Rhs` must be explicitly specified For more information about this error, try `rustc --explain E0225`.
--> $DIR/issue-22560.rs:9:17
|
LL | trait Add<Rhs=Self> {
| ------------------- type parameter `Rhs` must be specified for this
...
LL | type Test = dyn Add + Sub;
| ^^^
|
= note: because of the default `Self` reference, type parameters must be specified on object types
help: set the type parameter to the desired type
|
LL | type Test = dyn Add<Rhs> + Sub;
| +++++
error[E0393]: the type parameter `Rhs` must be explicitly specified
--> $DIR/issue-22560.rs:9:23
|
LL | trait Sub<Rhs=Self> {
| ------------------- type parameter `Rhs` must be specified for this
...
LL | type Test = dyn Add + Sub;
| ^^^
|
= note: because of the default `Self` reference, type parameters must be specified on object types
help: set the type parameter to the desired type
|
LL | type Test = dyn Add + Sub<Rhs>;
| +++++
error: aborting due to 4 previous errors
Some errors have detailed explanations: E0191, E0225, E0393.
For more information about an error, try `rustc --explain E0191`.

4
tests/ui/associated-types/missing-associated-types.rs
View file

@ -11,16 +11,12 @@ trait Fine<Rhs>: Div<Rhs, Output = Rhs> {}
type Foo<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs>; type Foo<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs>;
//~^ ERROR only auto traits can be used as additional traits in a trait object //~^ ERROR only auto traits can be used as additional traits in a trait object
//~| ERROR the value of the associated types
type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>; type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
//~^ ERROR only auto traits can be used as additional traits in a trait object //~^ ERROR only auto traits can be used as additional traits in a trait object
//~| ERROR the value of the associated types
type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>; type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>;
//~^ ERROR only auto traits can be used as additional traits in a trait object //~^ ERROR only auto traits can be used as additional traits in a trait object
//~| ERROR the value of the associated types
type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>; type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>;
//~^ ERROR only auto traits can be used as additional traits in a trait object //~^ ERROR only auto traits can be used as additional traits in a trait object
//~| ERROR the value of the associated types
type Bal<Rhs> = dyn X<Rhs>; type Bal<Rhs> = dyn X<Rhs>;
//~^ ERROR the value of the associated types //~^ ERROR the value of the associated types

83
tests/ui/associated-types/missing-associated-types.stderr
View file

@ -9,26 +9,8 @@ LL | type Foo<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs>;
= help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs> {}` = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs> {}`
= note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
error[E0191]: the value of the associated types `A` in `Y`, `Output` in `Add`, `Output` in `Mul`, `Output` in `Sub` must be specified
--> $DIR/missing-associated-types.rs:12:21
|
LL | type A;
| ------ `A` defined here
...
LL | type Foo<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Y<Rhs>;
| ^^^^^^^^ ^^^^^^^^ ^^^^^^ ^^^^^^ associated type `A` must be specified
| | | |
| | | associated type `Output` must be specified
| | associated type `Output` must be specified
| associated type `Output` must be specified
|
help: specify the associated types
|
LL | type Foo<Rhs> = dyn Add<Rhs, Output = Type> + Sub<Rhs, Output = Type> + X<Rhs, Output = Type> + Y<Rhs, A = Type>;
| ~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~
error[E0225]: only auto traits can be used as additional traits in a trait object error[E0225]: only auto traits can be used as additional traits in a trait object
--> $DIR/missing-associated-types.rs:15:32 --> $DIR/missing-associated-types.rs:14:32
| |
LL | type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>; LL | type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
| -------- ^^^^^^^^ additional non-auto trait | -------- ^^^^^^^^ additional non-auto trait
@ -38,33 +20,8 @@ LL | type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
= help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs> {}` = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs> {}`
= note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
error[E0191]: the value of the associated types `A` and `B` in `Z`, `Output` and `Output` in `Div`, `Output` in `Add`, `Output` in `Mul`, `Output` in `Sub` must be specified
--> $DIR/missing-associated-types.rs:15:21
|
LL | type A;
| ------ `A` defined here
LL | type B;
| ------ `B` defined here
...
LL | type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
| ^^^^^^^^ ^^^^^^^^ ^^^^^^ ^^^^^^ associated types `A`, `B`, `Output` must be specified
| | | |
| | | associated types `Output` (from trait `Div`), `Output` (from trait `Mul`) must be specified
| | associated type `Output` must be specified
| associated type `Output` must be specified
|
help: consider introducing a new type parameter, adding `where` constraints using the fully-qualified path to the associated types
--> $DIR/missing-associated-types.rs:15:43
|
LL | type Bar<Rhs> = dyn Add<Rhs> + Sub<Rhs> + X<Rhs> + Z<Rhs>;
| ^^^^^^
help: specify the associated types
|
LL | type Bar<Rhs> = dyn Add<Rhs, Output = Type> + Sub<Rhs, Output = Type> + X<Rhs> + Z<Rhs, A = Type, B = Type, Output = Type>;
| ~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error[E0225]: only auto traits can be used as additional traits in a trait object error[E0225]: only auto traits can be used as additional traits in a trait object
--> $DIR/missing-associated-types.rs:18:32 --> $DIR/missing-associated-types.rs:16:32
| |
LL | type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>; LL | type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>;
| -------- ^^^^^^^^ additional non-auto trait | -------- ^^^^^^^^ additional non-auto trait
@ -74,25 +31,8 @@ LL | type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>;
= help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + Y<Rhs> {}` = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + Y<Rhs> {}`
= note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
error[E0191]: the value of the associated types `A` in `Y`, `Output` in `Add`, `Output` in `Sub` must be specified
--> $DIR/missing-associated-types.rs:18:21
|
LL | type A;
| ------ `A` defined here
...
LL | type Baz<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Y<Rhs>;
| ^^^^^^^^ ^^^^^^^^ ^^^^^^ associated type `A` must be specified
| | |
| | associated type `Output` must be specified
| associated type `Output` must be specified
|
help: specify the associated types
|
LL | type Baz<Rhs> = dyn Add<Rhs, Output = Type> + Sub<Rhs, Output = Type> + Y<Rhs, A = Type>;
| ~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~
error[E0225]: only auto traits can be used as additional traits in a trait object error[E0225]: only auto traits can be used as additional traits in a trait object
--> $DIR/missing-associated-types.rs:21:32 --> $DIR/missing-associated-types.rs:18:32
| |
LL | type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>; LL | type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>;
| -------- ^^^^^^^^ additional non-auto trait | -------- ^^^^^^^^ additional non-auto trait
@ -102,28 +42,15 @@ LL | type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>;
= help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + Fine<Rhs> {}` = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Add<Rhs> + Sub<Rhs> + Fine<Rhs> {}`
= note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
error[E0191]: the value of the associated types `Output` in `Add`, `Output` in `Sub` must be specified
--> $DIR/missing-associated-types.rs:21:21
|
LL | type Bat<Rhs> = dyn Add<Rhs> + Sub<Rhs> + Fine<Rhs>;
| ^^^^^^^^ ^^^^^^^^ associated type `Output` must be specified
| |
| associated type `Output` must be specified
|
help: specify the associated types
|
LL | type Bat<Rhs> = dyn Add<Rhs, Output = Type> + Sub<Rhs, Output = Type> + Fine<Rhs>;
| ~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~
error[E0191]: the value of the associated types `Output` in `Div`, `Output` in `Mul` must be specified error[E0191]: the value of the associated types `Output` in `Div`, `Output` in `Mul` must be specified
--> $DIR/missing-associated-types.rs:24:21 --> $DIR/missing-associated-types.rs:20:21
| |
LL | type Bal<Rhs> = dyn X<Rhs>; LL | type Bal<Rhs> = dyn X<Rhs>;
| ^^^^^^ associated types `Output` (from trait `Div`), `Output` (from trait `Mul`) must be specified | ^^^^^^ associated types `Output` (from trait `Div`), `Output` (from trait `Mul`) must be specified
| |
= help: consider introducing a new type parameter, adding `where` constraints using the fully-qualified path to the associated types = help: consider introducing a new type parameter, adding `where` constraints using the fully-qualified path to the associated types
error: aborting due to 9 previous errors error: aborting due to 5 previous errors
Some errors have detailed explanations: E0191, E0225. Some errors have detailed explanations: E0191, E0225.
For more information about an error, try `rustc --explain E0191`. For more information about an error, try `rustc --explain E0191`.

3
tests/ui/const-generics/not_wf_param_in_rpitit.rs
View file

@ -3,9 +3,6 @@
trait Trait<const N: dyn Trait = bar> { trait Trait<const N: dyn Trait = bar> {
//~^ ERROR: cannot find value `bar` in this scope //~^ ERROR: cannot find value `bar` in this scope
//~| ERROR: cycle detected when computing type of `Trait::N` //~| ERROR: cycle detected when computing type of `Trait::N`
//~| ERROR: the trait `Trait` cannot be made into an object
//~| ERROR: the trait `Trait` cannot be made into an object
//~| ERROR: the trait `Trait` cannot be made into an object
async fn a() {} async fn a() {}
} }

76
tests/ui/const-generics/not_wf_param_in_rpitit.stderr
View file

@ -18,77 +18,7 @@ LL | trait Trait<const N: dyn Trait = bar> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
error[E0038]: the trait `Trait` cannot be made into an object error: aborting due to 2 previous errors
--> $DIR/not_wf_param_in_rpitit.rs:3:22
|
LL | trait Trait<const N: dyn Trait = bar> {
| ^^^^^^^^^ `Trait` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/not_wf_param_in_rpitit.rs:9:14
|
LL | trait Trait<const N: dyn Trait = bar> {
| ----- this trait cannot be made into an object...
...
LL | async fn a() {}
| ^ ...because associated function `a` has no `self` parameter
help: consider turning `a` into a method by giving it a `&self` argument
|
LL | async fn a(&self) {}
| +++++
help: alternatively, consider constraining `a` so it does not apply to trait objects
|
LL | async fn a() where Self: Sized {}
| +++++++++++++++++
error[E0038]: the trait `Trait` cannot be made into an object Some errors have detailed explanations: E0391, E0425.
--> $DIR/not_wf_param_in_rpitit.rs:3:13 For more information about an error, try `rustc --explain E0391`.
|
LL | trait Trait<const N: dyn Trait = bar> {
| ^^^^^^^^^^^^^^^^^^^^^^^^ `Trait` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/not_wf_param_in_rpitit.rs:9:14
|
LL | trait Trait<const N: dyn Trait = bar> {
| ----- this trait cannot be made into an object...
...
LL | async fn a() {}
| ^ ...because associated function `a` has no `self` parameter
help: consider turning `a` into a method by giving it a `&self` argument
|
LL | async fn a(&self) {}
| +++++
help: alternatively, consider constraining `a` so it does not apply to trait objects
|
LL | async fn a() where Self: Sized {}
| +++++++++++++++++
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/not_wf_param_in_rpitit.rs:3:13
|
LL | trait Trait<const N: dyn Trait = bar> {
| ^^^^^^^^^^^^^^^^^^^^^^^^ `Trait` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/not_wf_param_in_rpitit.rs:9:14
|
LL | trait Trait<const N: dyn Trait = bar> {
| ----- this trait cannot be made into an object...
...
LL | async fn a() {}
| ^ ...because associated function `a` has no `self` parameter
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
help: consider turning `a` into a method by giving it a `&self` argument
|
LL | async fn a(&self) {}
| +++++
help: alternatively, consider constraining `a` so it does not apply to trait objects
|
LL | async fn a() where Self: Sized {}
| +++++++++++++++++
error: aborting due to 5 previous errors
Some errors have detailed explanations: E0038, E0391, E0425.
For more information about an error, try `rustc --explain E0038`.

1
tests/ui/issues/issue-23024.rs
View file

@ -8,5 +8,4 @@ fn main()
println!("{:?}",(vfnfer[0] as dyn Fn)(3)); println!("{:?}",(vfnfer[0] as dyn Fn)(3));
//~^ ERROR the precise format of `Fn`-family traits' //~^ ERROR the precise format of `Fn`-family traits'
//~| ERROR missing generics for trait `Fn` //~| ERROR missing generics for trait `Fn`
//~| ERROR the value of the associated type `Output` in `FnOnce`
} }

10
tests/ui/issues/issue-23024.stderr
View file

@ -19,13 +19,7 @@ help: add missing generic argument
LL | println!("{:?}",(vfnfer[0] as dyn Fn<Args>)(3)); LL | println!("{:?}",(vfnfer[0] as dyn Fn<Args>)(3));
| ++++++ | ++++++
error[E0191]: the value of the associated type `Output` in `FnOnce` must be specified error: aborting due to 2 previous errors
--> $DIR/issue-23024.rs:8:39
|
LL | println!("{:?}",(vfnfer[0] as dyn Fn)(3));
| ^^ help: specify the associated type: `Fn::<Output = Type>`
error: aborting due to 3 previous errors Some errors have detailed explanations: E0107, E0658.
Some errors have detailed explanations: E0107, E0191, E0658.
For more information about an error, try `rustc --explain E0107`. For more information about an error, try `rustc --explain E0107`.

1
tests/ui/issues/issue-34373.rs
View file

@ -6,7 +6,6 @@ trait Trait<T> {
pub struct Foo<T = Box<Trait<DefaultFoo>>>; //~ ERROR cycle detected pub struct Foo<T = Box<Trait<DefaultFoo>>>; //~ ERROR cycle detected
//~^ ERROR `T` is never used //~^ ERROR `T` is never used
//~| ERROR `Trait` cannot be made into an object
type DefaultFoo = Foo; type DefaultFoo = Foo;
fn main() { fn main() {

30
tests/ui/issues/issue-34373.stderr
View file

@ -5,7 +5,7 @@ LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>;
| ^^^^^^^^^^ | ^^^^^^^^^^
| |
note: ...which requires expanding type alias `DefaultFoo`... note: ...which requires expanding type alias `DefaultFoo`...
--> $DIR/issue-34373.rs:10:19 --> $DIR/issue-34373.rs:9:19
| |
LL | type DefaultFoo = Foo; LL | type DefaultFoo = Foo;
| ^^^ | ^^^
@ -17,28 +17,6 @@ LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/issue-34373.rs:7:24
|
LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>;
| ^^^^^^^^^^^^^^^^^ `Trait` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/issue-34373.rs:4:8
|
LL | trait Trait<T> {
| ----- this trait cannot be made into an object...
LL | fn foo(_: T) {}
| ^^^ ...because associated function `foo` has no `self` parameter
help: consider turning `foo` into a method by giving it a `&self` argument
|
LL | fn foo(&self, _: T) {}
| ++++++
help: alternatively, consider constraining `foo` so it does not apply to trait objects
|
LL | fn foo(_: T) where Self: Sized {}
| +++++++++++++++++
error[E0392]: type parameter `T` is never used error[E0392]: type parameter `T` is never used
--> $DIR/issue-34373.rs:7:16 --> $DIR/issue-34373.rs:7:16
| |
@ -48,7 +26,7 @@ LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>;
= help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData` = help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`
= help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead
error: aborting due to 3 previous errors error: aborting due to 2 previous errors
Some errors have detailed explanations: E0038, E0391, E0392. Some errors have detailed explanations: E0391, E0392.
For more information about an error, try `rustc --explain E0038`. For more information about an error, try `rustc --explain E0391`.

3
tests/ui/suggestions/use-type-argument-instead-of-assoc-type.rs
View file

@ -5,8 +5,7 @@ pub trait T<X, Y> {
} }
pub struct Foo { pub struct Foo {
i: Box<dyn T<usize, usize, usize, usize, B=usize>>, i: Box<dyn T<usize, usize, usize, usize, B=usize>>,
//~^ ERROR must be specified //~^ ERROR trait takes 2 generic arguments but 4 generic arguments were supplied
//~| ERROR trait takes 2 generic arguments but 4 generic arguments were supplied
} }

17
tests/ui/suggestions/use-type-argument-instead-of-assoc-type.stderr
View file

@ -14,19 +14,6 @@ help: replace the generic bounds with the associated types
LL | i: Box<dyn T<usize, usize, A = usize, C = usize, B=usize>>, LL | i: Box<dyn T<usize, usize, A = usize, C = usize, B=usize>>,
| +++ +++ | +++ +++
error[E0191]: the value of the associated types `C` and `A` in `T` must be specified error: aborting due to 1 previous error
--> $DIR/use-type-argument-instead-of-assoc-type.rs:7:16
|
LL | type A;
| ------ `A` defined here
LL | type B;
LL | type C;
| ------ `C` defined here
...
LL | i: Box<dyn T<usize, usize, usize, usize, B=usize>>,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ associated types `A`, `C` must be specified
error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0107`.
Some errors have detailed explanations: E0107, E0191.
For more information about an error, try `rustc --explain E0107`.

3
tests/ui/traits/bad-sized.rs
View file

@ -3,7 +3,4 @@ trait Trait {}
pub fn main() { pub fn main() {
let x: Vec<dyn Trait + Sized> = Vec::new(); let x: Vec<dyn Trait + Sized> = Vec::new();
//~^ ERROR only auto traits can be used as additional traits in a trait object //~^ ERROR only auto traits can be used as additional traits in a trait object
//~| ERROR the size for values of type
//~| ERROR the size for values of type
//~| ERROR the size for values of type
} }

35
tests/ui/traits/bad-sized.stderr
View file

@ -9,37 +9,6 @@ LL | let x: Vec<dyn Trait + Sized> = Vec::new();
= help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Trait + Sized {}` = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Trait + Sized {}`
= note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
error[E0277]: the size for values of type `dyn Trait` cannot be known at compilation time error: aborting due to 1 previous error
--> $DIR/bad-sized.rs:4:12
|
LL | let x: Vec<dyn Trait + Sized> = Vec::new();
| ^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `dyn Trait`
note: required by an implicit `Sized` bound in `Vec`
--> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
error[E0277]: the size for values of type `dyn Trait` cannot be known at compilation time For more information about this error, try `rustc --explain E0225`.
--> $DIR/bad-sized.rs:4:37
|
LL | let x: Vec<dyn Trait + Sized> = Vec::new();
| ^^^^^^^^^^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `dyn Trait`
note: required by a bound in `Vec::<T>::new`
--> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
error[E0277]: the size for values of type `dyn Trait` cannot be known at compilation time
--> $DIR/bad-sized.rs:4:37
|
LL | let x: Vec<dyn Trait + Sized> = Vec::new();
| ^^^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `dyn Trait`
note: required by an implicit `Sized` bound in `Vec`
--> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
error: aborting due to 4 previous errors
Some errors have detailed explanations: E0225, E0277.
For more information about an error, try `rustc --explain E0225`.

1
tests/ui/traits/issue-32963.rs
View file

@ -7,5 +7,4 @@ fn size_of_copy<T: Copy+?Sized>() -> usize { mem::size_of::<T>() }
fn main() { fn main() {
size_of_copy::<dyn Misc + Copy>(); size_of_copy::<dyn Misc + Copy>();
//~^ ERROR only auto traits can be used as additional traits in a trait object //~^ ERROR only auto traits can be used as additional traits in a trait object
//~| ERROR the trait bound `dyn Misc: Copy` is not satisfied
} }

17
tests/ui/traits/issue-32963.stderr
View file

@ -9,19 +9,6 @@ LL | size_of_copy::<dyn Misc + Copy>();
= help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Misc + Copy {}` = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Misc + Copy {}`
= note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>
error[E0277]: the trait bound `dyn Misc: Copy` is not satisfied error: aborting due to 1 previous error
--> $DIR/issue-32963.rs:8:20
|
LL | size_of_copy::<dyn Misc + Copy>();
| ^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `dyn Misc`
|
note: required by a bound in `size_of_copy`
--> $DIR/issue-32963.rs:5:20
|
LL | fn size_of_copy<T: Copy+?Sized>() -> usize { mem::size_of::<T>() }
| ^^^^ required by this bound in `size_of_copy`
error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0225`.
Some errors have detailed explanations: E0225, E0277.
For more information about an error, try `rustc --explain E0225`.

8
tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.rs
View file

@ -1,11 +1,6 @@
trait Trait<const N: Trait = bar> { trait Trait<const N: Trait = bar> {
//~^ ERROR cannot find value `bar` in this scope //~^ ERROR cannot find value `bar` in this scope
//~| ERROR cycle detected when computing type of `Trait::N` //~| ERROR cycle detected when computing type of `Trait::N`
//~| ERROR the trait `Trait` cannot be made into an object
//~| ERROR the trait `Trait` cannot be made into an object
//~| ERROR the trait `Trait` cannot be made into an object
//~| WARN trait objects without an explicit `dyn` are deprecated [bare_trait_objects]
//~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
//~| WARN trait objects without an explicit `dyn` are deprecated [bare_trait_objects] //~| WARN trait objects without an explicit `dyn` are deprecated [bare_trait_objects]
//~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021! //~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
fn fnc<const N: Trait = u32>(&self) -> Trait { fn fnc<const N: Trait = u32>(&self) -> Trait {
@ -13,9 +8,6 @@ trait Trait<const N: Trait = bar> {
//~| ERROR expected value, found builtin type `u32` //~| ERROR expected value, found builtin type `u32`
//~| ERROR defaults for const parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions //~| ERROR defaults for const parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
//~| ERROR associated item referring to unboxed trait object for its own trait //~| ERROR associated item referring to unboxed trait object for its own trait
//~| ERROR the trait `Trait` cannot be made into an object
//~| WARN trait objects without an explicit `dyn` are deprecated [bare_trait_objects]
//~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
//~| WARN trait objects without an explicit `dyn` are deprecated [bare_trait_objects] //~| WARN trait objects without an explicit `dyn` are deprecated [bare_trait_objects]
//~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021! //~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
//~| WARN trait objects without an explicit `dyn` are deprecated [bare_trait_objects] //~| WARN trait objects without an explicit `dyn` are deprecated [bare_trait_objects]

133
tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.stderr
View file

@ -1,5 +1,5 @@
error[E0403]: the name `N` is already used for a generic parameter in this item's generic parameters error[E0403]: the name `N` is already used for a generic parameter in this item's generic parameters
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:18 --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:6:18
| |
LL | trait Trait<const N: Trait = bar> { LL | trait Trait<const N: Trait = bar> {
| - first use of `N` | - first use of `N`
@ -14,13 +14,13 @@ LL | trait Trait<const N: Trait = bar> {
| ^^^ not found in this scope | ^^^ not found in this scope
error[E0423]: expected value, found builtin type `u32` error[E0423]: expected value, found builtin type `u32`
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:29 --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:6:29
| |
LL | fn fnc<const N: Trait = u32>(&self) -> Trait { LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^ not a value | ^^^ not a value
error[E0425]: cannot find value `bar` in this scope error[E0425]: cannot find value `bar` in this scope
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:23:9 --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:15:9
| |
LL | bar LL | bar
| ^^^ not found in this scope | ^^^ not found in this scope
@ -53,27 +53,8 @@ LL | trait Trait<const N: Trait = bar> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
error: defaults for const parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:12
|
LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^^^^^^^^^^^^^^^^^^
warning: trait objects without an explicit `dyn` are deprecated warning: trait objects without an explicit `dyn` are deprecated
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:21 --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:6:44
|
LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^^^
|
= warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
help: if this is a dyn-compatible trait, use `dyn`
|
LL | fn fnc<const N: dyn Trait = u32>(&self) -> Trait {
| +++
warning: trait objects without an explicit `dyn` are deprecated
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:44
| |
LL | fn fnc<const N: Trait = u32>(&self) -> Trait { LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^^^ | ^^^^^
@ -85,54 +66,27 @@ help: if this is a dyn-compatible trait, use `dyn`
LL | fn fnc<const N: Trait = u32>(&self) -> dyn Trait { LL | fn fnc<const N: Trait = u32>(&self) -> dyn Trait {
| +++ | +++
warning: trait objects without an explicit `dyn` are deprecated error: defaults for const parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:22 --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:6:12
| |
LL | trait Trait<const N: Trait = bar> { LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^^^ | ^^^^^^^^^^^^^^^^^^^^
warning: trait objects without an explicit `dyn` are deprecated
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:6:21
|
LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^^^
| |
= warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021! = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html> = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
help: if this is a dyn-compatible trait, use `dyn` help: if this is a dyn-compatible trait, use `dyn`
| |
LL | trait Trait<const N: dyn Trait = bar> { LL | fn fnc<const N: dyn Trait = u32>(&self) -> Trait {
| +++ | +++
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:22
|
LL | trait Trait<const N: Trait = bar> {
| ^^^^^ `Trait` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:8
|
LL | trait Trait<const N: Trait = bar> {
| ----- this trait cannot be made into an object...
...
LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^ ...because method `fnc` has generic type parameters
= help: consider moving `fnc` to another trait
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:13
|
LL | trait Trait<const N: Trait = bar> {
| ^^^^^^^^^^^^^^^^^^^^ `Trait` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:8
|
LL | trait Trait<const N: Trait = bar> {
| ----- this trait cannot be made into an object...
...
LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^ ...because method `fnc` has generic type parameters
= help: consider moving `fnc` to another trait
error: associated item referring to unboxed trait object for its own trait error: associated item referring to unboxed trait object for its own trait
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:44 --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:6:44
| |
LL | trait Trait<const N: Trait = bar> { LL | trait Trait<const N: Trait = bar> {
| ----- in this trait | ----- in this trait
@ -145,54 +99,7 @@ help: you might have meant to use `Self` to refer to the implementing type
LL | fn fnc<const N: Trait = u32>(&self) -> Self { LL | fn fnc<const N: Trait = u32>(&self) -> Self {
| ~~~~ | ~~~~
warning: trait objects without an explicit `dyn` are deprecated error: aborting due to 7 previous errors; 3 warnings emitted
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:21
|
LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^^^
|
= warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
help: if this is a dyn-compatible trait, use `dyn`
|
LL | fn fnc<const N: dyn Trait = u32>(&self) -> Trait {
| +++
error[E0038]: the trait `Trait` cannot be made into an object Some errors have detailed explanations: E0391, E0403, E0423, E0425.
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:21 For more information about an error, try `rustc --explain E0391`.
|
LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^^^ `Trait` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:8
|
LL | trait Trait<const N: Trait = bar> {
| ----- this trait cannot be made into an object...
...
LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^ ...because method `fnc` has generic type parameters
= help: consider moving `fnc` to another trait
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:13
|
LL | trait Trait<const N: Trait = bar> {
| ^^^^^^^^^^^^^^^^^^^^ `Trait` cannot be made into an object
|
note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:11:8
|
LL | trait Trait<const N: Trait = bar> {
| ----- this trait cannot be made into an object...
...
LL | fn fnc<const N: Trait = u32>(&self) -> Trait {
| ^^^ ...because method `fnc` has generic type parameters
= help: consider moving `fnc` to another trait
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
error: aborting due to 11 previous errors; 5 warnings emitted
Some errors have detailed explanations: E0038, E0391, E0403, E0423, E0425.
For more information about an error, try `rustc --explain E0038`.