error[E0038]: the trait `NotObjectSafe` cannot be made into an object
  --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:21:13
   |
LL | fn car() -> dyn NotObjectSafe {
   |             ^^^^^^^^^^^^^^^^^ `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
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:29:17
   |
LL | fn cat() -> Box<dyn NotObjectSafe> {
   |                 ^^^^^^^^^^^^^^^^^ `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
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[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

Some errors have detailed explanations: E0038, E0746.
For more information about an error, try `rustc --explain E0038`.