diff options
Diffstat (limited to 'src/test/ui/numbers-arithmetic/overflowing-rsh-4.rs')
-rw-r--r-- | src/test/ui/numbers-arithmetic/overflowing-rsh-4.rs | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/src/test/ui/numbers-arithmetic/overflowing-rsh-4.rs b/src/test/ui/numbers-arithmetic/overflowing-rsh-4.rs new file mode 100644 index 000000000..ce7f818e3 --- /dev/null +++ b/src/test/ui/numbers-arithmetic/overflowing-rsh-4.rs @@ -0,0 +1,24 @@ +// 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, const_err)] + +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); +} |