From 9febb895a8bbefb8ed673b3553f79e1499fc0ca4 Mon Sep 17 00:00:00 2001 From: Alex Crichton Date: Fri, 15 May 2015 09:18:14 -0700 Subject: std: Make abs() panic on overflow in debug mode Debug overflow checks for arithmetic negation landed in #24500, at which time the `abs` method on signed integers was changed to using `wrapping_neg` to ensure that the function never panicked. This implied that `abs` of `INT_MIN` would return `INT_MIN`, another negative value. When this change was back-ported to beta, however, in #24708, the `wrapping_neg` function had not yet been backported, so the implementation was changed in #24785 to `!self + 1`. This change had the unintended side effect of enabling debug overflow checks for the `abs` function. Consequently, the current state of affairs is that the beta branch checks for overflow in debug mode for `abs` and the nightly branch does not. This commit alters the behavior of nightly to have `abs` always check for overflow in debug mode. This change is more consistent with the way the standard library treats overflow as well, and it is also not a breaking change as it's what the beta branch currently does (albeit if by accident). cc #25378 --- src/test/run-pass/int-abs-overflow.rs | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 src/test/run-pass/int-abs-overflow.rs (limited to 'src/test') diff --git a/src/test/run-pass/int-abs-overflow.rs b/src/test/run-pass/int-abs-overflow.rs new file mode 100644 index 00000000000..3f50a7d6c02 --- /dev/null +++ b/src/test/run-pass/int-abs-overflow.rs @@ -0,0 +1,21 @@ +// 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// compile-flags: -Z force-overflow-checks=on + +use std::thread; + +fn main() { + assert!(thread::spawn(|| i8::min_value().abs()).join().is_err()); + assert!(thread::spawn(|| i16::min_value().abs()).join().is_err()); + assert!(thread::spawn(|| i32::min_value().abs()).join().is_err()); + assert!(thread::spawn(|| i64::min_value().abs()).join().is_err()); + assert!(thread::spawn(|| isize::min_value().abs()).join().is_err()); +} -- cgit 1.4.1-3-g733a5