rust/src/test/run-fail/overflowing-sub.rs
Alex Crichton d5d834551c rustc: Add a debug_assertions #[cfg] directive
This commit is an implementation of [RFC 563][rfc] which adds a new
`cfg(debug_assertions)` directive which is specially recognized and calculated
by the compiler. The flag is turned off at any optimization level greater than 1
and may also be explicitly controlled through the `-C debug-assertions`
flag.

[rfc]: https://github.com/rust-lang/rfcs/pull/563

The `debug_assert!` and `debug_assert_eq!` macros now respect this instead of
the `ndebug` variable and `ndebug` no longer holds any meaning to the standard
library.

Code which was previously relying on `not(ndebug)` to gate expensive code should
be updated to rely on `debug_assertions` instead.

Closes #22492
[breaking-change]
2015-03-05 14:51:38 -08:00

20 lines
699 B
Rust

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// error-pattern:thread '<main>' panicked at 'arithmetic operation overflowed'
// compile-flags: -C debug-assertions
// (Work around constant-evaluation)
fn value() -> u8 { 42 }
fn main() {
let _x = value() - (value() + 1);
}