error: casting a character literal to `u8` truncates
  --> tests/ui/char_lit_as_u8.rs:5:13
   |
LL |     let _ = '❤' as u8;
   |             ^^^^^^^^^
   |
   = note: `char` is four bytes wide, but `u8` is a single byte
   = note: `-D clippy::char-lit-as-u8` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::char_lit_as_u8)]`

error: aborting due to 1 previous error