error: casting i32 to i64 may become silently lossy if types change
  --> $DIR/types.rs:19:23
   |
19 |     let c_i64 : i64 = c as i64;
   |                       ^^^^^^^^ help: try: `i64::from(c)`
   |
   = note: `-D clippy::cast-lossless` implied by `-D warnings`

error: aborting due to previous error