Tweaks to equality comparisons for slices/arrays/vectors

Author: petrochenkov

src/libcollections/vec.rs

@@ -1501,69 +1501,34 @@ impl<T> Extend<T> for Vec<T> {
     }
 }
 
-impl<A, B> PartialEq<Vec<B>> for Vec<A> where A: PartialEq<B> {
-    #[inline]
-    fn eq(&self, other: &Vec<B>) -> bool { PartialEq::eq(&**self, &**other) }
-    #[inline]
-    fn ne(&self, other: &Vec<B>) -> bool { PartialEq::ne(&**self, &**other) }
-}
-
-macro_rules! impl_eq {
-    ($lhs:ty, $rhs:ty) => {
-        impl<'b, A, B> PartialEq<$rhs> for $lhs where A: PartialEq<B> {
-            #[inline]
-            fn eq(&self, other: &$rhs) -> bool { PartialEq::eq(&**self, &**other) }
-            #[inline]
-            fn ne(&self, other: &$rhs) -> bool { PartialEq::ne(&**self, &**other) }
-        }
-
-        impl<'b, A, B> PartialEq<$lhs> for $rhs where B: PartialEq<A> {
-            #[inline]
-            fn eq(&self, other: &$lhs) -> bool { PartialEq::eq(&**self, &**other) }
-            #[inline]
-            fn ne(&self, other: &$lhs) -> bool { PartialEq::ne(&**self, &**other) }
-        }
+__impl_slice_eq1! { Vec<A>, Vec<B> }
+__impl_slice_eq2! { Vec<A>, &'b [B] }
+__impl_slice_eq2! { Vec<A>, &'b mut [B] }
+__impl_slice_eq2! { CowVec<'a, A>, &'b [B], Clone }
+__impl_slice_eq2! { CowVec<'a, A>, &'b mut [B], Clone }
+__impl_slice_eq2! { CowVec<'a, A>, Vec<B>, Clone }
+
+macro_rules! array_impls {
+    ($($N: expr)+) => {
+        $(
+            // NOTE: some less important impls are omitted to reduce code bloat
+            __impl_slice_eq2! { Vec<A>, [B; $N] }
+            __impl_slice_eq2! { Vec<A>, &'b [B; $N] }
+            // __impl_slice_eq2! { Vec<A>, &'b mut [B; $N] }
+            // __impl_slice_eq2! { CowVec<'a, A>, [B; $N], Clone }
+            // __impl_slice_eq2! { CowVec<'a, A>, &'b [B; $N], Clone }
+            // __impl_slice_eq2! { CowVec<'a, A>, &'b mut [B; $N], Clone }
+        )+
     }
 }
 
-impl_eq! { Vec<A>, &'b [B] }
-impl_eq! { Vec<A>, &'b mut [B] }
-
-impl<'a, A, B> PartialEq<Vec<B>> for Cow<'a, [A]> where A: PartialEq<B> + Clone {
-    #[inline]
-    fn eq(&self, other: &Vec<B>) -> bool { PartialEq::eq(&**self, &**other) }
-    #[inline]
-    fn ne(&self, other: &Vec<B>) -> bool { PartialEq::ne(&**self, &**other) }
+array_impls! {
+     0  1  2  3  4  5  6  7  8  9
+    10 11 12 13 14 15 16 17 18 19
+    20 21 22 23 24 25 26 27 28 29
+    30 31 32
 }
 
-impl<'a, A, B> PartialEq<Cow<'a, [A]>> for Vec<B> where A: Clone, B: PartialEq<A> {
-    #[inline]
-    fn eq(&self, other: &Cow<'a, [A]>) -> bool { PartialEq::eq(&**self, &**other) }
-    #[inline]
-    fn ne(&self, other: &Cow<'a, [A]>) -> bool { PartialEq::ne(&**self, &**other) }
-}
-
-macro_rules! impl_eq_for_cowvec {
-    ($rhs:ty) => {
-        impl<'a, 'b, A, B> PartialEq<$rhs> for Cow<'a, [A]> where A: PartialEq<B> + Clone {
-            #[inline]
-            fn eq(&self, other: &$rhs) -> bool { PartialEq::eq(&**self, &**other) }
-            #[inline]
-            fn ne(&self, other: &$rhs) -> bool { PartialEq::ne(&**self, &**other) }
-        }
-
-        impl<'a, 'b, A, B> PartialEq<Cow<'a, [A]>> for $rhs where A: Clone, B: PartialEq<A> {
-            #[inline]
-            fn eq(&self, other: &Cow<'a, [A]>) -> bool { PartialEq::eq(&**self, &**other) }
-            #[inline]
-            fn ne(&self, other: &Cow<'a, [A]>) -> bool { PartialEq::ne(&**self, &**other) }
-        }
-    }
-}
-
-impl_eq_for_cowvec! { &'b [B] }
-impl_eq_for_cowvec! { &'b mut [B] }
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: PartialOrd> PartialOrd for Vec<T> {
     #[inline]
@@ -2480,7 +2445,7 @@ mod tests {
     fn test_into_boxed_slice() {
         let xs = vec![1, 2, 3];
         let ys = xs.into_boxed_slice();
-        assert_eq!(ys, [1, 2, 3]);
+        assert_eq!(&*ys, [1, 2, 3]);
     }
 
     #[test]

src/libcore/array.rs

@@ -19,8 +19,7 @@ use cmp::{PartialEq, Eq, PartialOrd, Ord, Ordering};
 use fmt;
 use hash::{Hash, self};
 use iter::IntoIterator;
-use marker::Copy;
-use ops::Deref;
+use marker::{Copy, Sized};
 use option::Option;
 use slice::{Iter, IterMut, SliceExt};
 
@@ -76,47 +75,13 @@ macro_rules! array_impls {
                 }
             }
 
-            #[stable(feature = "rust1", since = "1.0.0")]
-            impl<A, B> PartialEq<[B; $N]> for [A; $N] where A: PartialEq<B> {
-                #[inline]
-                fn eq(&self, other: &[B; $N]) -> bool {
-                    &self[..] == &other[..]
-                }
-                #[inline]
-                fn ne(&self, other: &[B; $N]) -> bool {
-                    &self[..] != &other[..]
-                }
-            }
-
-            #[stable(feature = "rust1", since = "1.0.0")]
-            impl<'a, A, B, Rhs> PartialEq<Rhs> for [A; $N] where
-                A: PartialEq<B>,
-                Rhs: Deref<Target=[B]>,
-            {
-                #[inline(always)]
-                fn eq(&self, other: &Rhs) -> bool {
-                    PartialEq::eq(&self[..], &**other)
-                }
-                #[inline(always)]
-                fn ne(&self, other: &Rhs) -> bool {
-                    PartialEq::ne(&self[..], &**other)
-                }
-            }
-
-            #[stable(feature = "rust1", since = "1.0.0")]
-            impl<'a, A, B, Lhs> PartialEq<[B; $N]> for Lhs where
-                A: PartialEq<B>,
-                Lhs: Deref<Target=[A]>
-            {
-                #[inline(always)]
-                fn eq(&self, other: &[B; $N]) -> bool {
-                    PartialEq::eq(&**self, &other[..])
-                }
-                #[inline(always)]
-                fn ne(&self, other: &[B; $N]) -> bool {
-                    PartialEq::ne(&**self, &other[..])
-                }
-            }
+            // NOTE: some less important impls are omitted to reduce code bloat
+            __impl_slice_eq1! { [A; $N], [B; $N] }
+            __impl_slice_eq2! { [A; $N], [B] }
+            __impl_slice_eq2! { [A; $N], &'b [B] }
+            __impl_slice_eq2! { [A; $N], &'b mut [B] }
+            // __impl_slice_eq2! { [A; $N], &'b [B; $N] }
+            // __impl_slice_eq2! { [A; $N], &'b mut [B; $N] }
 
             #[stable(feature = "rust1", since = "1.0.0")]
             impl<T:Eq> Eq for [T; $N] { }

src/libcore/cmp_macros.rs

@@ -0,0 +1,50 @@
+// 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.
+
+// Utility macros for implementing PartialEq on slice-like types
+
+#![doc(hidden)]
+
+#[macro_export]
+macro_rules! __impl_slice_eq1 {
+    ($Lhs: ty, $Rhs: ty) => {
+        #[stable(feature = "rust1", since = "1.0.0")]
+        impl<'a, 'b, A, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> {
+            #[inline]
+            fn eq(&self, other: &$Rhs) -> bool { &self[..] == &other[..] }
+            #[inline]
+            fn ne(&self, other: &$Rhs) -> bool { &self[..] != &other[..] }
+        }
+    }
+}
+
+#[macro_export]
+macro_rules! __impl_slice_eq2 {
+    ($Lhs: ty, $Rhs: ty) => {
+        __impl_slice_eq2! { $Lhs, $Rhs, Sized }
+    };
+    ($Lhs: ty, $Rhs: ty, $Bound: ident) => {
+        #[stable(feature = "rust1", since = "1.0.0")]
+        impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> {
+            #[inline]
+            fn eq(&self, other: &$Rhs) -> bool { &self[..] == &other[..] }
+            #[inline]
+            fn ne(&self, other: &$Rhs) -> bool { &self[..] != &other[..] }
+        }
+
+        #[stable(feature = "rust1", since = "1.0.0")]
+        impl<'a, 'b, A: $Bound, B> PartialEq<$Lhs> for $Rhs where B: PartialEq<A> {
+            #[inline]
+            fn eq(&self, other: &$Lhs) -> bool { &self[..] == &other[..] }
+            #[inline]
+            fn ne(&self, other: &$Lhs) -> bool { &self[..] != &other[..] }
+        }
+    }
+}

src/libcore/lib.rs

@@ -72,6 +72,9 @@
 #[macro_use]
 mod macros;
 
+#[macro_use]
+mod cmp_macros;
+
 #[path = "num/float_macros.rs"]
 #[macro_use]
 mod float_macros;

src/libstd/ffi/c_str.rs

@@ -371,7 +371,7 @@ impl CStr {
 
 impl PartialEq for CStr {
     fn eq(&self, other: &CStr) -> bool {
-        self.to_bytes().eq(&other.to_bytes())
+        self.to_bytes().eq(other.to_bytes())
     }
 }
 impl Eq for CStr {}