vlib/v/checker/tests/asm_immutable_err.vv:9:9: error: `c` is immutable, declare it with `mut` to make it mutable
    7 |         add eax, b
    8 |         mov c, eax
    9 |         ; =r (c) // output
      |               ^
   10 |         ; r (a) // input
   11 |           r (b)