diff options
Diffstat (limited to 'tests/ui/impl-trait')
| -rw-r--r-- | tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.rs | 5 | ||||
| -rw-r--r-- | tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr | 79 |
2 files changed, 79 insertions, 5 deletions
diff --git a/tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.rs b/tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.rs index ab3086c78b3..068f7d3eea6 100644 --- a/tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.rs +++ b/tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.rs @@ -19,6 +19,7 @@ impl NotObjectSafe for B { } fn car() -> dyn NotObjectSafe { //~ ERROR the trait `NotObjectSafe` cannot be made into an object +//~^ ERROR return type cannot have an unboxed trait object if true { return A; } @@ -27,9 +28,9 @@ fn car() -> dyn NotObjectSafe { //~ ERROR the trait `NotObjectSafe` cannot be ma fn cat() -> Box<dyn NotObjectSafe> { //~ ERROR the trait `NotObjectSafe` cannot be made into an if true { - return Box::new(A); + return Box::new(A); //~ ERROR cannot be made into an object } - Box::new(B) + Box::new(B) //~ ERROR cannot be made into an object } fn main() {} diff --git a/tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr b/tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr index 37c96d9bc4e..fc9c30abf13 100644 --- a/tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr +++ b/tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr @@ -24,7 +24,7 @@ LL | fn foo() -> Self where Self: Sized; | +++++++++++++++++ error[E0038]: the trait `NotObjectSafe` cannot be made into an object - --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:28:17 + --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:29:17 | LL | fn cat() -> Box<dyn NotObjectSafe> { | ^^^^^^^^^^^^^^^^^ `NotObjectSafe` cannot be made into an object @@ -48,6 +48,79 @@ help: alternatively, consider constraining `foo` so it does not apply to trait o LL | fn foo() -> Self where Self: Sized; | +++++++++++++++++ -error: aborting due to 2 previous errors +error[E0746]: return type cannot have an unboxed trait object + --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:21:13 + | +LL | fn car() -> dyn NotObjectSafe { + | ^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time + | +help: return an `impl Trait` instead of a `dyn Trait`, if all returned values are the same type + | +LL | fn car() -> impl NotObjectSafe { + | ~~~~ +help: box the return type, and wrap all of the returned values in `Box::new` + | +LL ~ fn car() -> Box<dyn NotObjectSafe> { +LL | +LL | if true { +LL ~ return Box::new(A); +LL | } +LL ~ Box::new(B) + | + +error[E0038]: the trait `NotObjectSafe` cannot be made into an object + --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:31:16 + | +LL | return Box::new(A); + | ^^^^^^^^^^^ `NotObjectSafe` cannot be made into an object + | +note: for a trait to be "object safe" 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/object-unsafe-trait-in-return-position-dyn-trait.rs:3:8 + | +LL | trait NotObjectSafe { + | ------------- this trait cannot be made into an object... +LL | fn foo() -> Self; + | ^^^ ...because associated function `foo` has no `self` parameter + = help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `NotObjectSafe` for this new enum and using it instead: + A + B + = note: required for the cast from `Box<A>` to `Box<(dyn NotObjectSafe + 'static)>` +help: consider turning `foo` into a method by giving it a `&self` argument + | +LL | fn foo(&self) -> Self; + | +++++ +help: alternatively, consider constraining `foo` so it does not apply to trait objects + | +LL | fn foo() -> Self where Self: Sized; + | +++++++++++++++++ + +error[E0038]: the trait `NotObjectSafe` cannot be made into an object + --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:33:5 + | +LL | Box::new(B) + | ^^^^^^^^^^^ `NotObjectSafe` cannot be made into an object + | +note: for a trait to be "object safe" 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/object-unsafe-trait-in-return-position-dyn-trait.rs:3:8 + | +LL | trait NotObjectSafe { + | ------------- this trait cannot be made into an object... +LL | fn foo() -> Self; + | ^^^ ...because associated function `foo` has no `self` parameter + = help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `NotObjectSafe` for this new enum and using it instead: + A + B + = note: required for the cast from `Box<B>` to `Box<(dyn NotObjectSafe + 'static)>` +help: consider turning `foo` into a method by giving it a `&self` argument + | +LL | fn foo(&self) -> Self; + | +++++ +help: alternatively, consider constraining `foo` so it does not apply to trait objects + | +LL | fn foo() -> Self where Self: Sized; + | +++++++++++++++++ + +error: aborting due to 5 previous errors -For more information about this error, try `rustc --explain E0038`. +Some errors have detailed explanations: E0038, E0746. +For more information about an error, try `rustc --explain E0038`. |