std: Change assert_eq!() to use {} instead of {:?}

Formatting via reflection has been a little questionable for some time now, and
it's a little unfortunate that one of the standard macros will silently use
reflection when you weren't expecting it. This adds small bits of code bloat to
libraries, as well as not always being necessary. In light of this information,
this commit switches assert_eq!() to using {} in the error message instead of
{:?}.

In updating existing code, there were a few error cases that I encountered:

* It's impossible to define Show for [T, ..N]. I think DST will alleviate this
  because we can define Show for [T].
* A few types here and there just needed a #[deriving(Show)]
* Type parameters needed a Show bound, I often moved this to `assert!(a == b)`
* `Path` doesn't implement `Show`, so assert_eq!() cannot be used on two paths.
  I don't think this is much of a regression though because {:?} on paths looks
  awful (it's a byte array).

Concretely speaking, this shaved 10K off a 656K binary. Not a lot, but sometime
significant for smaller binaries.

Author: alexcrichton

src/doc/guide-container.md

@@ -384,7 +384,7 @@ the trailing underscore is a workaround for issue #5898 and will be removed.
 ~~~
 let mut ys = [1, 2, 3, 4, 5];
 ys.mut_iter().reverse_();
-assert_eq!(ys, [5, 4, 3, 2, 1]);
+assert!(ys == [5, 4, 3, 2, 1]);
 ~~~
 
 ## Random-access iterators

src/doc/tutorial.md

@@ -1688,7 +1688,7 @@ let x = Rc::new([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
 let y = x.clone(); // a new owner
 let z = x; // this moves `x` into `z`, rather than creating a new owner
 
-assert_eq!(*z.borrow(), [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+assert!(*z.borrow() == [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
 
 // the variable is mutable, but not the contents of the box
 let mut a = Rc::new([10, 9, 8, 7, 6, 5, 4, 3, 2, 1]);
@@ -1707,7 +1707,7 @@ let x = Gc::new([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
 let y = x; // does not perform a move, unlike with `Rc`
 let z = x;
 
-assert_eq!(*z.borrow(), [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+assert!(*z.borrow() == [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
 ~~~
 
 With shared ownership, mutability cannot be inherited so the boxes are always immutable. However,

src/libcollections/bitv.rs

@@ -1542,7 +1542,7 @@ mod tests {
 
         let mut b = a.clone();
 
-        assert_eq!(&a, &b);
+        assert!(a == b);
 
         assert!(b.remove(&1));
         assert!(a.contains(&1));
@@ -1561,7 +1561,7 @@ mod tests {
         let mut r = rng();
         let mut bitv = 0 as uint;
         b.iter(|| {
-            bitv |= (1 << ((r.next_u32() as uint) % uint::BITS));
+            bitv |= 1 << ((r.next_u32() as uint) % uint::BITS);
             &bitv
         })
     }

src/libcollections/dlist.rs

@@ -982,11 +982,11 @@ mod tests {
     fn test_eq() {
         let mut n: DList<u8> = list_from([]);
         let mut m = list_from([]);
-        assert_eq!(&n, &m);
+        assert!(n == m);
         n.push_front(1);
         assert!(n != m);
         m.push_back(1);
-        assert_eq!(&n, &m);
+        assert!(n == m);
 
         let n = list_from([2,3,4]);
         let m = list_from([1,2,3]);

src/libcollections/enum_set.rs

@@ -141,7 +141,7 @@ mod test {
 
     use enum_set::{EnumSet, CLike};
 
-    #[deriving(Eq)]
+    #[deriving(Eq, Show)]
     #[repr(uint)]
     enum Foo {
         A, B, C

src/libcollections/hashmap.rs

@@ -1065,7 +1065,7 @@ mod test_map {
         let mut observed = 0;
         for (k, v) in m.iter() {
             assert_eq!(*v, *k * 2);
-            observed |= (1 << *k);
+            observed |= 1 << *k;
         }
         assert_eq!(observed, 0xFFFF_FFFF);
     }
@@ -1293,7 +1293,7 @@ mod test_set {
         }
         let mut observed = 0;
         for k in a.iter() {
-            observed |= (1 << *k);
+            observed |= 1 << *k;
         }
         assert_eq!(observed, 0xFFFF_FFFF);
     }

src/libcollections/list.rs

@@ -153,7 +153,7 @@ mod tests {
     #[test]
     fn test_from_vec_empty() {
         let empty : list::List<int> = List::from_vec([]);
-        assert_eq!(empty, Nil::<int>);
+        assert!(empty == Nil::<int>);
     }
 
     #[test]
@@ -222,8 +222,8 @@ mod tests {
 
     #[test]
     fn test_append() {
-        assert_eq!(List::from_vec([1, 2, 3, 4]),
-                   List::from_vec([1, 2]).append(List::from_vec([3, 4])));
+        assert!(List::from_vec([1, 2, 3, 4]) ==
+                List::from_vec([1, 2]).append(List::from_vec([3, 4])));
     }
 
     #[test]
@@ -232,6 +232,6 @@ mod tests {
         let new_list = list.unshift(0);
         assert_eq!(list.len(), 1u);
         assert_eq!(new_list.len(), 2u);
-        assert_eq!(new_list, List::from_vec([0, 1]));
+        assert!(new_list == List::from_vec([0, 1]));
     }
 }

src/libcollections/lru_cache.rs

@@ -277,7 +277,7 @@ mod tests {
 
     fn assert_opt_eq<V: Eq>(opt: Option<&V>, v: V) {
         assert!(opt.is_some());
-        assert_eq!(opt.unwrap(), &v);
+        assert!(opt.unwrap() == &v);
     }
 
     #[test]

src/libcollections/ringbuf.rs

@@ -409,6 +409,7 @@ mod tests {
     use deque::Deque;
     use std::clone::Clone;
     use std::cmp::Eq;
+    use std::fmt::Show;
     use super::RingBuf;
 
     #[test]
@@ -493,7 +494,7 @@ mod tests {
     }
 
     #[cfg(test)]
-    fn test_parameterized<T:Clone + Eq>(a: T, b: T, c: T, d: T) {
+    fn test_parameterized<T:Clone + Eq + Show>(a: T, b: T, c: T, d: T) {
         let mut deq = RingBuf::new();
         assert_eq!(deq.len(), 0);
         deq.push_front(a.clone());
@@ -578,21 +579,21 @@ mod tests {
         })
     }
 
-    #[deriving(Clone, Eq)]
+    #[deriving(Clone, Eq, Show)]
     enum Taggy {
         One(int),
         Two(int, int),
         Three(int, int, int),
     }
 
-    #[deriving(Clone, Eq)]
+    #[deriving(Clone, Eq, Show)]
     enum Taggypar<T> {
         Onepar(int),
         Twopar(int, int),
         Threepar(int, int, int),
     }
 
-    #[deriving(Clone, Eq)]
+    #[deriving(Clone, Eq, Show)]
     struct RecCy {
         x: int,
         y: int,
@@ -812,7 +813,7 @@ mod tests {
     #[test]
     fn test_eq() {
         let mut d = RingBuf::new();
-        assert_eq!(&d, &RingBuf::with_capacity(0));
+        assert!(d == RingBuf::with_capacity(0));
         d.push_front(137);
         d.push_front(17);
         d.push_front(42);
@@ -822,11 +823,11 @@ mod tests {
         e.push_back(17);
         e.push_back(137);
         e.push_back(137);
-        assert_eq!(&e, &d);
+        assert!(&e == &d);
         e.pop_back();
         e.push_back(0);
         assert!(e != d);
         e.clear();
-        assert_eq!(e, RingBuf::new());
+        assert!(e == RingBuf::new());
     }
 }

src/libgetopts/lib.rs

@@ -1361,7 +1361,7 @@ mod tests {
                                 aliases: ~[] }];
         let verbose = reqopt("b", "banana", "some bananas", "VAL");
 
-        assert_eq!(verbose.long_to_short(), short);
+        assert!(verbose.long_to_short() == short);
     }
 
     #[test]