| //@ build-fail |
| //@ compile-flags: -C debug-assertions |
| |
| // This function is checking that our (type-based) automatic |
| // truncation does not sidestep the overflow checking. |
| |
| #![deny(arithmetic_overflow)] |
| |
| fn main() { |
| // this signals overflow when checking is on |
| let x = 2_i8 >> 17; |
| //~^ ERROR: this arithmetic operation will overflow |
| |
| // ... but when checking is off, the fallback will truncate the |
| // input to its lower three bits (= 1). Note that this is *not* |
| // the behavior of the x86 processor for 8- and 16-bit types, |
| // but it is necessary to avoid undefined behavior from LLVM. |
| // |
| // We check that here, by ensuring the result is not zero; if |
| // overflow checking is turned off, then this assertion will pass |
| // (and the compiletest driver will report that the test did not |
| // produce the error expected above). |
| assert_eq!(x, 1_i8); |
| } |
