test-rust-lang. md

[haaami01]

#![allow(unused)]
fn main() {
let mut vec1 = vec![1, 2, 3, 4];
let vec2 = vec![10, 20, 30, 40];
vec1.extend(vec2);
}

(Playground)

Errors:

   Compiling playground v0.0.1 (/playground)
    Finished dev [unoptimized + debuginfo] target(s) in 1.54s
     Running `target/debug/playground`