rustc 1.79.0-nightly (e3181b091 2024-04-18) binary: rustc commit-hash: e3181b091e88321f5ea149afed6db0edf0a4f37b commit-date: 2024-04-18 host: aarch64-apple-darwin release: 1.79.0-nightly LLVM version: 18.1.4 

warning: trait objects without an explicit `dyn` are deprecated --> r_crushed_473555.rs:2:12 | 2 | data: (Copy, fn() -> T), | ^^^^ | = 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: `#[warn(bare_trait_objects)]` on by default help: if this is an object-safe trait, use `dyn` | 2 | data: (dyn Copy, fn() -> T), | +++ error[E0038]: the trait `Copy` cannot be made into an object --> r_crushed_473555.rs:2:12 | 2 | data: (Copy, fn() -> T), | ^^^^ `Copy` cannot be made into an object | = note: the trait cannot be made into an object because it requires `Self: Sized` = 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> error[E0277]: the size for values of type `(dyn Copy + 'static)` cannot be known at compilation time --> r_crushed_473555.rs:2:11 | 2 | data: (Copy, fn() -> T), | ^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time | = help: the trait `Sized` is not implemented for `(dyn Copy + 'static)` = note: only the last element of a tuple may have a dynamically sized type error[E0277]: `(dyn Copy + 'static)` cannot be shared between threads safely --> r_crushed_473555.rs:19:19 | 19 | static EMPTY_SET: LazyLock<A<i32>> = LazyLock::new(A::default); | ^^^^^^^^^^^^^^^^ `(dyn Copy + 'static)` cannot be shared between threads safely | = help: within `LazyLock<A>`, the trait `Sync` is not implemented for `(dyn Copy + 'static)`, which is required by `LazyLock<A>: Sync` = note: required because it appears within the type `((dyn Copy + 'static), fn() -> A)` note: required because it appears within the type `LazyLock<A>` --> r_crushed_473555.rs:1:8 | 1 | struct LazyLock<T> { | ^^^^^^^^ = note: shared static variables must have a type that implements `Sync`