1 warning: trait objects without an explicit `dyn` are deprecated
2 --> $DIR/not-on-bare-trait.rs:7:12
4 LL | fn foo(_x: Foo + Send) {
7 = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
8 = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
9 = note: `#[warn(bare_trait_objects)]` on by default
12 LL | fn foo(_x: dyn Foo + Send) {
15 error[E0277]: the size for values of type `(dyn Foo + Send + 'static)` cannot be known at compilation time
16 --> $DIR/not-on-bare-trait.rs:7:8
18 LL | fn foo(_x: Foo + Send) {
19 | ^^ doesn't have a size known at compile-time
21 = help: the trait `Sized` is not implemented for `(dyn Foo + Send + 'static)`
22 = help: unsized fn params are gated as an unstable feature
23 help: you can use `impl Trait` as the argument type
25 LL | fn foo(_x: impl Foo + Send) {
27 help: function arguments must have a statically known size, borrowed types always have a known size
29 LL | fn foo(_x: &Foo + Send) {
32 error: aborting due to previous error; 1 warning emitted
34 For more information about this error, try `rustc --explain E0277`.