2 Checks for the use of `.extend(s.chars())` where s is a
6 `.push_str(s)` is clearer
11 let def = String::from("def");
12 let mut s = String::new();
13 s.extend(abc.chars());
14 s.extend(def.chars());
16 The correct use would be:
19 let def = String::from("def");
20 let mut s = String::new();