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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 'shift operation overflowed'
12 // compile-flags: -C debug-assertions
14 // This function is checking that our automatic truncation does not
15 // sidestep the overflow checking.
17 // (Work around constant-evaluation)
18 fn id
<T
>(x
: T
) -> T { x }
21 // this signals overflow when checking is on
22 let x
= 1_i8 << id(17);
24 // ... but when checking is off, the fallback will truncate the
25 // input to its lower three bits (= 1). Note that this is *not*
26 // the behavior of the x86 processor for 8- and 16-bit types,
27 // but it is necessary to avoid undefined behavior from LLVM.
29 // We check that here, by ensuring the result has only been
30 // shifted by one place; if overflow checking is turned off, then
31 // this assertion will pass (and the compiletest driver will
32 // report that the test did not produce the error expected above).