warning: unused variable: `str11`, #[warn(unused_variables)] on by default
 --> /in/foo.rs:7:9
  |
7 |     let mut str11 :Vec<&str>;
  |         ^^^^^^^^^

warning: unused variable: `str21`, #[warn(unused_variables)] on by default
 --> /in/foo.rs:8:9
  |
8 |     let mut str21 :Vec<&str>;
  |         ^^^^^^^^^

warning: variable does not need to be mutable, #[warn(unused_mut)] on by default
 --> /in/foo.rs:7:9
  |
7 |     let mut str11 :Vec<&str>;
  |         ^^^^^^^^^

warning: variable does not need to be mutable, #[warn(unused_mut)] on by default
 --> /in/foo.rs:8:9
  |
8 |     let mut str21 :Vec<&str>;
  |         ^^^^^^^^^