Allow T op= &T for built-in numeric types T

src/libcore/internal_macros.rs

@@ -68,3 +68,21 @@ macro_rules! forward_ref_binop {
         }
     }
 }
+
+// implements "T op= &U", based on "T op= U"
+// where U is expected to be `Copy`able
+macro_rules! forward_ref_op_assign {
+    (impl $imp:ident, $method:ident for $t:ty, $u:ty) => {
+        forward_ref_op_assign!(impl $imp, $method for $t, $u,
+                #[stable(feature = "op_assign_builtins_by_ref", since = "1.18.0")]);
+    };
+    (impl $imp:ident, $method:ident for $t:ty, $u:ty, #[$attr:meta]) => {
+        #[$attr]
+        impl<'a> $imp<&'a $u> for $t {
+            #[inline]
+            fn $method(&mut self, other: &'a $u) {
+                $imp::$method(self, *other);
+            }
+        }
+    }
+}

src/libcore/num/wrapping.rs

@@ -35,6 +35,7 @@ macro_rules! sh_impl_signed {
                 *self = *self << other;
             }
         }
+        forward_ref_op_assign! { impl ShlAssign, shl_assign for Wrapping<$t>, $f }
 
         #[stable(feature = "rust1", since = "1.0.0")]
         impl Shr<$f> for Wrapping<$t> {
@@ -57,6 +58,7 @@ macro_rules! sh_impl_signed {
                 *self = *self >> other;
             }
         }
+        forward_ref_op_assign! { impl ShrAssign, shr_assign for Wrapping<$t>, $f }
     )
 }
 
@@ -79,6 +81,7 @@ macro_rules! sh_impl_unsigned {
                 *self = *self << other;
             }
         }
+        forward_ref_op_assign! { impl ShlAssign, shl_assign for Wrapping<$t>, $f }
 
         #[stable(feature = "rust1", since = "1.0.0")]
         impl Shr<$f> for Wrapping<$t> {
@@ -97,6 +100,7 @@ macro_rules! sh_impl_unsigned {
                 *self = *self >> other;
             }
         }
+        forward_ref_op_assign! { impl ShrAssign, shr_assign for Wrapping<$t>, $f }
     )
 }
 
@@ -141,6 +145,7 @@ macro_rules! wrapping_impl {
                 *self = *self + other;
             }
         }
+        forward_ref_op_assign! { impl AddAssign, add_assign for Wrapping<$t>, Wrapping<$t> }
 
         #[stable(feature = "rust1", since = "1.0.0")]
         impl Sub for Wrapping<$t> {
@@ -161,6 +166,7 @@ macro_rules! wrapping_impl {
                 *self = *self - other;
             }
         }
+        forward_ref_op_assign! { impl SubAssign, sub_assign for Wrapping<$t>, Wrapping<$t> }
 
         #[stable(feature = "rust1", since = "1.0.0")]
         impl Mul for Wrapping<$t> {
@@ -181,6 +187,7 @@ macro_rules! wrapping_impl {
                 *self = *self * other;
             }
         }
+        forward_ref_op_assign! { impl MulAssign, mul_assign for Wrapping<$t>, Wrapping<$t> }
 
         #[stable(feature = "wrapping_div", since = "1.3.0")]
         impl Div for Wrapping<$t> {
@@ -201,6 +208,7 @@ macro_rules! wrapping_impl {
                 *self = *self / other;
             }
         }
+        forward_ref_op_assign! { impl DivAssign, div_assign for Wrapping<$t>, Wrapping<$t> }
 
         #[stable(feature = "wrapping_impls", since = "1.7.0")]
         impl Rem for Wrapping<$t> {
@@ -221,6 +229,7 @@ macro_rules! wrapping_impl {
                 *self = *self % other;
             }
         }
+        forward_ref_op_assign! { impl RemAssign, rem_assign for Wrapping<$t>, Wrapping<$t> }
 
         #[stable(feature = "rust1", since = "1.0.0")]
         impl Not for Wrapping<$t> {
@@ -253,6 +262,7 @@ macro_rules! wrapping_impl {
                 *self = *self ^ other;
             }
         }
+        forward_ref_op_assign! { impl BitXorAssign, bitxor_assign for Wrapping<$t>, Wrapping<$t> }
 
         #[stable(feature = "rust1", since = "1.0.0")]
         impl BitOr for Wrapping<$t> {
@@ -273,6 +283,7 @@ macro_rules! wrapping_impl {
                 *self = *self | other;
             }
         }
+        forward_ref_op_assign! { impl BitOrAssign, bitor_assign for Wrapping<$t>, Wrapping<$t> }
 
         #[stable(feature = "rust1", since = "1.0.0")]
         impl BitAnd for Wrapping<$t> {
@@ -293,6 +304,7 @@ macro_rules! wrapping_impl {
                 *self = *self & other;
             }
         }
+        forward_ref_op_assign! { impl BitAndAssign, bitand_assign for Wrapping<$t>, Wrapping<$t> }
 
         #[stable(feature = "wrapping_neg", since = "1.10.0")]
         impl Neg for Wrapping<$t> {

src/libcore/ops.rs

@@ -1346,6 +1346,8 @@ macro_rules! add_assign_impl {
             #[rustc_inherit_overflow_checks]
             fn add_assign(&mut self, other: $t) { *self += other }
         }
+
+        forward_ref_op_assign! { impl AddAssign, add_assign for $t, $t }
     )+)
 }
 
@@ -1403,6 +1405,8 @@ macro_rules! sub_assign_impl {
             #[rustc_inherit_overflow_checks]
             fn sub_assign(&mut self, other: $t) { *self -= other }
         }
+
+        forward_ref_op_assign! { impl SubAssign, sub_assign for $t, $t }
     )+)
 }
 
@@ -1449,6 +1453,8 @@ macro_rules! mul_assign_impl {
             #[rustc_inherit_overflow_checks]
             fn mul_assign(&mut self, other: $t) { *self *= other }
         }
+
+        forward_ref_op_assign! { impl MulAssign, mul_assign for $t, $t }
     )+)
 }
 
@@ -1494,6 +1500,8 @@ macro_rules! div_assign_impl {
             #[inline]
             fn div_assign(&mut self, other: $t) { *self /= other }
         }
+
+        forward_ref_op_assign! { impl DivAssign, div_assign for $t, $t }
     )+)
 }
 
@@ -1539,6 +1547,8 @@ macro_rules! rem_assign_impl {
             #[inline]
             fn rem_assign(&mut self, other: $t) { *self %= other }
         }
+
+        forward_ref_op_assign! { impl RemAssign, rem_assign for $t, $t }
     )+)
 }
 
@@ -1626,6 +1636,8 @@ macro_rules! bitand_assign_impl {
             #[inline]
             fn bitand_assign(&mut self, other: $t) { *self &= other }
         }
+
+        forward_ref_op_assign! { impl BitAndAssign, bitand_assign for $t, $t }
     )+)
 }
 
@@ -1671,6 +1683,8 @@ macro_rules! bitor_assign_impl {
             #[inline]
             fn bitor_assign(&mut self, other: $t) { *self |= other }
         }
+
+        forward_ref_op_assign! { impl BitOrAssign, bitor_assign for $t, $t }
     )+)
 }
 
@@ -1716,6 +1730,8 @@ macro_rules! bitxor_assign_impl {
             #[inline]
             fn bitxor_assign(&mut self, other: $t) { *self ^= other }
         }
+
+        forward_ref_op_assign! { impl BitXorAssign, bitxor_assign for $t, $t }
     )+)
 }
 
@@ -1764,6 +1780,8 @@ macro_rules! shl_assign_impl {
                 *self <<= other
             }
         }
+
+        forward_ref_op_assign! { impl ShlAssign, shl_assign for $t, $f }
     )
 }
 
@@ -1830,6 +1848,8 @@ macro_rules! shr_assign_impl {
                 *self >>= other
             }
         }
+
+        forward_ref_op_assign! { impl ShrAssign, shr_assign for $t, $f }
     )
 }
 

src/test/run-pass/num-wrapping.rs

@@ -173,6 +173,15 @@ fn test_op_assigns() {
                 tmp.$op(Wrapping($rhs));
                 assert_eq!(black_box(tmp), Wrapping($ans));
             }
+
+            // also test that a &Wrapping<T> right-hand side is possible
+            {
+                let mut tmp = Wrapping($initial);
+                tmp = black_box(tmp);
+                tmp.$op(&Wrapping($rhs));
+                assert_eq!(black_box(tmp), Wrapping($ans));
+            }
+
             // FIXME(30524): Uncomment this test
             /*
             {

src/test/run-pass/op-assign-builtins-by-ref.rs

@@ -0,0 +1,84 @@
+// 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.
+
+fn main() {
+    // test compound assignment operators with ref as right-hand side,
+    // for each operator, with various types as operands.
+
+    // test AddAssign
+    {
+        let mut x = 3i8;
+        x += &2i8;
+        assert_eq!(x, 5i8);
+    }
+
+    // test SubAssign
+    {
+        let mut x = 7i16;
+        x -= &4;
+        assert_eq!(x, 3i16);
+    }
+
+    // test MulAssign
+    {
+        let mut x = 3f32;
+        x *= &3f32;
+        assert_eq!(x, 9f32);
+    }
+
+    // test DivAssign
+    {
+        let mut x = 6f64;
+        x /= &2f64;
+        assert_eq!(x, 3f64);
+    }
+
+    // test RemAssign
+    {
+        let mut x = 7i64;
+        x %= &4i64;
+        assert_eq!(x, 3i64);
+    }
+
+    // test BitOrAssign
+    {
+        let mut x = 0b1010u8;
+        x |= &0b1100u8;
+        assert_eq!(x, 0b1110u8);
+    }
+
+    // test BitAndAssign
+    {
+        let mut x = 0b1010u16;
+        x &= &0b1100u16;
+        assert_eq!(x, 0b1000u16);
+    }
+
+    // test BitXorAssign
+    {
+        let mut x = 0b1010u32;
+        x ^= &0b1100u32;
+        assert_eq!(x, 0b0110u32);
+    }
+
+    // test ShlAssign
+    {
+        let mut x = 0b1010u64;
+        x <<= &2u32;
+        assert_eq!(x, 0b101000u64);
+    }
+
+    // test ShrAssign
+    {
+        let mut x = 0b1010u64;
+        x >>= &2i16;
+        assert_eq!(x, 0b10u64);
+    }
+}