rust/tests/ui/consts/issue-23968-const-not-overflow.rs

// run-pass
const U8_MAX_HALF: u8 = !0u8 / 2;
const U16_MAX_HALF: u16 = !0u16 / 2;
const U32_MAX_HALF: u32 = !0u32 / 2;
const U64_MAX_HALF: u64 = !0u64 / 2;

fn main() {
    assert_eq!(U8_MAX_HALF, 0x7f);
    assert_eq!(U16_MAX_HALF, 0x7fff);
    assert_eq!(U32_MAX_HALF, 0x7fff_ffff);
    assert_eq!(U64_MAX_HALF, 0x7fff_ffff_ffff_ffff);
}
Add `// run-pass` annotations to all the tests under `ui/run-pass/`. (I may have accidentally added it to some auxilliary crates as well; my emacs-macro-based methodology was pretty crude.) 2018-08-30 12:18:55 +00:00			`// run-pass`
Fix compile-time integer overflow when using ! on unsigned values Since the values are stored in a u64 internally, we need to be mask away the high bits after applying the ! operator. Otherwise, these bits will be set to one, causing overflow. 2015-05-17 08:04:15 +00:00			`const U8_MAX_HALF: u8 = !0u8 / 2;`
			`const U16_MAX_HALF: u16 = !0u16 / 2;`
			`const U32_MAX_HALF: u32 = !0u32 / 2;`
			`const U64_MAX_HALF: u64 = !0u64 / 2;`

			`fn main() {`
			`assert_eq!(U8_MAX_HALF, 0x7f);`
			`assert_eq!(U16_MAX_HALF, 0x7fff);`
			`assert_eq!(U32_MAX_HALF, 0x7fff_ffff);`
			`assert_eq!(U64_MAX_HALF, 0x7fff_ffff_ffff_ffff);`
			`}`