1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // error-pattern:thread 'main' panicked at 'attempt to shift right with overflow'
12 // compile-flags: -C debug-assertions
14 // This function is checking that our (type-based) automatic
15 // truncation does not sidestep the overflow checking.
17 #![warn(exceeding_bitshifts)]
20 // this signals overflow when checking is on
23 // ... but when checking is off, the fallback will truncate the
24 // input to its lower three bits (= 1). Note that this is *not*
25 // the behavior of the x86 processor for 8- and 16-bit types,
26 // but it is necessary to avoid undefined behavior from LLVM.
28 // We check that here, by ensuring the result is not zero; if
29 // overflow checking is turned off, then this assertion will pass
30 // (and the compiletest driver will report that the test did not
31 // produce the error expected above).