在 Rust 中,这样做是有效的:
fn main() {
let a = [0; 32];
println!("{:?}", a);
}
但这个不会:
fn main() {
let a = [0; 33];
println!("{:?}", a);
}
编译错误:
error[E0277]: the trait bound `[{integer}; 33]: std::fmt::Debug` is not satisfied
--> src/main.rs:3:22
|
3 | println!("{:?}", a);
| ^ the trait `std::fmt::Debug` is not implemented for `[{integer}; 33]`
|
= note: `[{integer}; 33]` cannot be formatted using `:?`; if it is defined in your crate, add `#[derive(Debug)]` or manually implement it
= note: required by `std::fmt::Debug::fmt`
我假设std::fmt::Debug
函数能够以某种方式检测到长度最长为32个元素的类型,但随后就不再进行检测。那么为什么它不起作用呢?