error: format argument must be a string literal
  --> $DIR/bad_hello.rs:2:14
   |
LL |     println!(3 + 4);
   |              ^^^^^
   |
help: you might be missing a string literal to format with
   |
LL |     println!("{}", 3 + 4);
   |              +++++

error: format argument must be a string literal
  --> $DIR/bad_hello.rs:4:14
   |
LL |     println!(3, 4);
   |              ^
   |
help: you might be missing a string literal to format with
   |
LL |     println!("{} {}", 3, 4);
   |              ++++++++

error: aborting due to 2 previous errors