I'm new to rust. I copied this code from rust website documentation.
I tried to debug this but I think, it's from the compiler or invalid documentation.
fn main() {
let greeting = Some("Hello, World");
println!("{:?}", greeting);
let some_number = Some(5);
let some_string = Some("a string");
let absent_number: Option<i32> = None;
}
#[derive(Debug)]
enum Option<T> {
Some(T),
None
}
Output:
Some("Hello, World")
Errors:
Compiling playground v0.0.1 (/playground)
warning: unused variable: `some_number`
--> src/main.rs:5:9
|
5 | let some_number = Some(5);
| ^^^^^^^^^^^ help: consider prefixing with an underscore: `_some_number`
|
= note: #[warn(unused_variables)] on by default
warning: unused variable: `some_string`
--> src/main.rs:6:9
|
6 | let some_string = Some("a string");
| ^^^^^^^^^^^ help: consider prefixing with an underscore: `_some_string`
warning: unused variable: `absent_number`
--> src/main.rs:8:9
|
8 | let absent_number: Option<i32> = Option::None;
| ^^^^^^^^^^^^^ help: consider prefixing with an underscore: `_absent_number`
warning: variant is never constructed: `Some`
--> src/main.rs:13:5
|
13 | Some(T),
| ^^^^^^^
|
= note: #[warn(dead_code)] on by default
Finished dev [unoptimized + debuginfo] target(s) in 0.79s
Running `target/debug/playground`