rollup merge of #23945: pnkfelix/gate-u-negate

Feature-gate  unsigned unary negate.

Discussed in weekly meeting here: https://github.com/rust-lang/meeting-minutes/blob/master/weekly-meetings/2015-03-31.md#feature-gate--expr

and also in the internals thread here: http://internals.rust-lang.org/t/forbid-unsigned-integer/752

src/test/compile-fail/const-eval-overflow.rs

@@ -8,7 +8,10 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(negate_unsigned)]
+
 #![allow(unused_imports)]
+#![feature(negate_unsigned)]
 
 // Note: the relevant lint pass here runs before some of the constant
 // evaluation below (e.g. that performed by trans and llvm), so if you

src/test/compile-fail/enum-discrim-too-small.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(negate_unsigned)]
+
 #[repr(u8)] //~ NOTE discriminant type specified here
 enum Eu8 {
     Au8 = 23,

src/test/compile-fail/lint-exceeding-bitshifts.rs

@@ -8,10 +8,11 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(negate_unsigned)]
 #![deny(exceeding_bitshifts)]
 #![allow(unused_variables)]
 #![allow(dead_code)]
-#![feature(core)]
+#![feature(core, negate_unsigned)]
 
 fn main() {
       let n = 1u8 << 7;

src/test/compile-fail/lint-type-limits.rs

@@ -8,7 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(negate_unsigned)]
 #![allow(dead_code)]
+#![feature(negate_unsigned)]
 
 // compile-flags: -D unused-comparisons
 fn main() { }

src/test/run-pass/big-literals.rs

@@ -16,10 +16,10 @@
 #![deny(overflowing_literals)]
 
 pub fn main() {
-    assert_eq!(0xffffffff, (-1 as u32));
-    assert_eq!(4294967295, (-1 as u32));
-    assert_eq!(0xffffffffffffffff, (-1 as u64));
-    assert_eq!(18446744073709551615, (-1 as u64));
+    assert_eq!(0xffffffff, (!0 as u32));
+    assert_eq!(4294967295, (!0 as u32));
+    assert_eq!(0xffffffffffffffff, (!0 as u64));
+    assert_eq!(18446744073709551615, (!0 as u64));
 
     assert_eq!((-2147483648i32).wrapping_sub(1), 2147483647);
 }

src/test/run-pass/bitwise.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(negate_unsigned)]
 
 #[cfg(any(target_arch = "x86", target_arch = "arm"))]
 fn target() {

src/test/run-pass/intrinsics-integer.rs

@@ -10,6 +10,7 @@
 
 // pretty-expanded FIXME #23616
 
+#![feature(negate_unsigned)]
 #![feature(intrinsics)]
 
 mod rusti {

src/test/run-pass/issue-17074.rs

@@ -10,10 +10,10 @@
 
 // pretty-expanded FIXME #23616
 
-static X2: u64 = -1 as u16 as u64;
-static Y2: u64 = -1 as u32 as u64;
-const X: u64 = -1 as u16 as u64;
-const Y: u64 = -1 as u32 as u64;
+static X2: u64 = !0 as u16 as u64;
+static Y2: u64 = !0 as u32 as u64;
+const X: u64 = !0 as u16 as u64;
+const Y: u64 = !0 as u32 as u64;
 
 fn main() {
     assert_eq!(match 1 {