diff --git a/src/libcollections/binary_heap.rs b/src/libcollections/binary_heap.rs
index fca3b7b07dd2..93b864a007fc 100644
--- a/src/libcollections/binary_heap.rs
+++ b/src/libcollections/binary_heap.rs
@@ -228,17 +228,12 @@ pub struct PeekMut<'a, T: 'a + Ord> {
     sift: bool,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: Ord> fmt::Debug for PeekMut<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("PeekMut { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: Ord + fmt::Debug> fmt::Debug for PeekMut<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad(&format!("PeekMut({:?})", self.heap.data[0]))
+        f.debug_tuple("PeekMut")
+         .field(&self.heap.data[0])
+         .finish()
     }
 }
 
@@ -982,13 +977,6 @@ pub struct Iter<'a, T: 'a> {
     iter: slice::Iter<'a, T>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Iter<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BinaryHeap::Iter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -1046,13 +1034,6 @@ pub struct IntoIter<T> {
     iter: vec::IntoIter<T>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<T> fmt::Debug for IntoIter<T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BinaryHeap::IntoIter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -1101,17 +1082,12 @@ pub struct Drain<'a, T: 'a> {
     iter: vec::Drain<'a, T>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Drain<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BinaryHeap::Drain { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Drain<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad(&format!("BinaryHeap::Drain({:?})", self.iter))
+        f.debug_tuple("BinaryHeap::Drain")
+         .field(&self.iter)
+         .finish()
     }
 }
 
diff --git a/src/libcollections/btree/map.rs b/src/libcollections/btree/map.rs
index 0d8b9d4677bd..eb6a8ea26a3b 100644
--- a/src/libcollections/btree/map.rs
+++ b/src/libcollections/btree/map.rs
@@ -270,13 +270,6 @@ pub struct Iter<'a, K: 'a, V: 'a> {
     length: usize,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, K: 'a, V: 'a> fmt::Debug for Iter<'a, K, V> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeMap::Iter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for Iter<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -291,13 +284,6 @@ pub struct IterMut<'a, K: 'a, V: 'a> {
     length: usize,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, K: 'a, V: 'a> fmt::Debug for IterMut<'a, K, V> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeMap::IterMut { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for IterMut<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -313,13 +299,6 @@ pub struct IntoIter<K, V> {
     length: usize,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<K, V> fmt::Debug for IntoIter<K, V> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeMap::IntoIter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IntoIter<K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -337,13 +316,6 @@ pub struct Keys<'a, K: 'a, V: 'a> {
     inner: Iter<'a, K, V>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, K: 'a, V: 'a> fmt::Debug for Keys<'a, K, V> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeMap::Keys { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for Keys<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -357,13 +329,6 @@ pub struct Values<'a, K: 'a, V: 'a> {
     inner: Iter<'a, K, V>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, K: 'a, V: 'a> fmt::Debug for Values<'a, K, V> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeMap::Values { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for Values<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -377,13 +342,6 @@ pub struct ValuesMut<'a, K: 'a, V: 'a> {
     inner: IterMut<'a, K, V>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, K: 'a, V: 'a> fmt::Debug for ValuesMut<'a, K, V> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeMap::ValuesMut { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for ValuesMut<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -397,13 +355,6 @@ pub struct Range<'a, K: 'a, V: 'a> {
     back: Handle<NodeRef<marker::Immut<'a>, K, V, marker::Leaf>, marker::Edge>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, K: 'a, V: 'a> fmt::Debug for Range<'a, K, V> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeMap::Range { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for Range<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -420,13 +371,6 @@ pub struct RangeMut<'a, K: 'a, V: 'a> {
     _marker: PhantomData<&'a mut (K, V)>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, K: 'a, V: 'a> fmt::Debug for RangeMut<'a, K, V> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeMap::RangeMut { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for RangeMut<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
diff --git a/src/libcollections/btree/set.rs b/src/libcollections/btree/set.rs
index d9effde72042..f90d0df768b9 100644
--- a/src/libcollections/btree/set.rs
+++ b/src/libcollections/btree/set.rs
@@ -85,13 +85,6 @@ pub struct Iter<'a, T: 'a> {
     iter: Keys<'a, T, ()>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Iter<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeSet::Iter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -112,13 +105,6 @@ pub struct IntoIter<T> {
     iter: ::btree_map::IntoIter<T, ()>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<T> fmt::Debug for IntoIter<T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeSet::IntoIter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -136,13 +122,6 @@ pub struct Range<'a, T: 'a> {
     iter: ::btree_map::Range<'a, T, ()>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Range<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeSet::Range { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Range<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -162,13 +141,6 @@ pub struct Difference<'a, T: 'a> {
     b: Peekable<Iter<'a, T>>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Difference<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeSet::Difference { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Difference<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -191,13 +163,6 @@ pub struct SymmetricDifference<'a, T: 'a> {
     b: Peekable<Iter<'a, T>>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for SymmetricDifference<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeSet::SymmetricDifference { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for SymmetricDifference<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -219,13 +184,6 @@ pub struct Intersection<'a, T: 'a> {
     b: Peekable<Iter<'a, T>>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Intersection<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeSet::Intersection { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Intersection<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -247,13 +205,6 @@ pub struct Union<'a, T: 'a> {
     b: Peekable<Iter<'a, T>>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Union<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("BTreeSet::Union { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Union<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
diff --git a/src/libcollections/enum_set.rs b/src/libcollections/enum_set.rs
index 3e739fa4f957..e4498c176170 100644
--- a/src/libcollections/enum_set.rs
+++ b/src/libcollections/enum_set.rs
@@ -220,13 +220,6 @@ pub struct Iter<E> {
     marker: marker::PhantomData<E>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<E> fmt::Debug for Iter<E> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("EnumSet::Iter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<E: fmt::Debug> fmt::Debug for Iter<E> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
diff --git a/src/libcollections/linked_list.rs b/src/libcollections/linked_list.rs
index 112749d5b058..21be9ac1aab8 100644
--- a/src/libcollections/linked_list.rs
+++ b/src/libcollections/linked_list.rs
@@ -65,13 +65,6 @@ pub struct Iter<'a, T: 'a> {
     marker: PhantomData<&'a Node<T>>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Iter<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("LinkedList::Iter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -98,13 +91,6 @@ pub struct IterMut<'a, T: 'a> {
     len: usize,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for IterMut<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("LinkedList::IterMut { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for IterMut<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -121,13 +107,6 @@ pub struct IntoIter<T> {
     list: LinkedList<T>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<T> fmt::Debug for IntoIter<T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("LinkedList::IntoIter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -1125,13 +1104,6 @@ pub struct FrontPlace<'a, T: 'a> {
     node: IntermediateBox<Node<T>>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for FrontPlace<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("LinkedList::FrontPlace { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for FrontPlace<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -1185,13 +1157,6 @@ pub struct BackPlace<'a, T: 'a> {
     node: IntermediateBox<Node<T>>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for BackPlace<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("LinkedList::BackPlace { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for BackPlace<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
diff --git a/src/libcollections/vec.rs b/src/libcollections/vec.rs
index 4f6212a1709a..2b6343782b19 100644
--- a/src/libcollections/vec.rs
+++ b/src/libcollections/vec.rs
@@ -2092,13 +2092,6 @@ pub struct Drain<'a, T: 'a> {
     vec: Shared<Vec<T>>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Drain<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("Vec::Drain { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Drain<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -2178,13 +2171,6 @@ pub struct PlaceBack<'a, T: 'a> {
     vec: &'a mut Vec<T>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for PlaceBack<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("Vec::PlaceBack { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for PlaceBack<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
diff --git a/src/libcollections/vec_deque.rs b/src/libcollections/vec_deque.rs
index dfbfb240f460..11aacb0ff43d 100644
--- a/src/libcollections/vec_deque.rs
+++ b/src/libcollections/vec_deque.rs
@@ -1866,13 +1866,6 @@ pub struct Iter<'a, T: 'a> {
     head: usize,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Iter<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("VecDeque::Iter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -1954,13 +1947,6 @@ pub struct IterMut<'a, T: 'a> {
     head: usize,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for IterMut<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("VecDeque::IterMut { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for IterMut<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -2036,13 +2022,6 @@ pub struct IntoIter<T> {
     inner: VecDeque<T>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<T> fmt::Debug for IntoIter<T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("VecDeque::IntoIter { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -2095,13 +2074,6 @@ pub struct Drain<'a, T: 'a> {
     deque: Shared<VecDeque<T>>,
 }
 
-#[stable(feature = "collection_debug", since = "1.15.0")]
-impl<'a, T: 'a> fmt::Debug for Drain<'a, T> {
-    default fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad("VecDeque::Drain { .. }")
-    }
-}
-
 #[stable(feature = "collection_debug", since = "1.15.0")]
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for Drain<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {