error: arithmetic detected
  --> $DIR/arithmetic_side_effects.rs:50:21
   |
LL |     let mut _a = 1; _a += 1;
   |                     ^^^^^^^
   |
   = note: `-D clippy::arithmetic-side-effects` implied by `-D warnings`

error: arithmetic detected
  --> $DIR/arithmetic_side_effects.rs:52:26
   |
LL |     let mut _b = 1; _b = _b + 1;
   |                          ^^^^^^

error: arithmetic detected
  --> $DIR/arithmetic_side_effects.rs:54:26
   |
LL |     let mut _c = 1; _c = 1 + _c;
   |                          ^^^^^^

error: aborting due to 3 previous errors