diff --git a/src/adaptors/transform.rs b/src/adaptors/transform.rs
index 3aa2d3c8..5298599d 100644
--- a/src/adaptors/transform.rs
+++ b/src/adaptors/transform.rs
@@ -101,11 +101,11 @@ impl<M: Translate<V>, V, _0> Translate<V> for Transform<M, _0>
   { self.submat.inv_translate(v) }
 }
 
-impl<M: Copy, V: Translatable<V, Res>, Res: Translation<V>>
-Translatable<V, Transform<M, Res>> for Transform<M, V>
+impl<M: Copy, V: Translatable<V, V> + Translation<V>>
+Translatable<V, Transform<M, V>> for Transform<M, V>
 {
   #[inline]
-  fn translated(&self, t: &V) -> Transform<M, Res>
+  fn translated(&self, t: &V) -> Transform<M, V>
   { Transform::new(copy self.submat, self.subtrans.translated(t)) }
 }
 
@@ -146,7 +146,7 @@ impl<M: Rotate<V>, V, _0> Rotate<V> for Transform<M, _0>
 }
 
 impl<M: Rotatable<AV, Res> + One,
-     Res: Rotation<AV> + RMul<V>,
+     Res: Rotation<AV> + RMul<V> + One,
      V,
      AV>
 Rotatable<AV, Transform<Res, V>> for Transform<M, V>
@@ -189,7 +189,7 @@ transformation::Transform<V> for Transform<M, V>
 
 // FIXME: constraints are too restrictive.
 // Should be: Transformable<M2, // Transform<Res, V> ...
-impl<M: RMul<V> + Mul<M, M>, V: Add<V, V>>
+impl<M: RMul<V> + Mul<M, M> + Inv, V: Add<V, V> + Neg<V>>
 Transformable<Transform<M, V>, Transform<M, V>> for Transform<M, V>
 {
   fn transformed(&self, t: &Transform<M, V>) -> Transform<M, V>
diff --git a/src/dvec.rs b/src/dvec.rs
index 00b38688..8673cce7 100644
--- a/src/dvec.rs
+++ b/src/dvec.rs
@@ -13,7 +13,7 @@ use traits::norm::Norm;
 use traits::translation::{Translation, Translatable};
 use traits::scalar_op::{ScalarMul, ScalarDiv, ScalarAdd, ScalarSub};
 
-#[deriving(Eq, Ord, ToStr, Clone)]
+#[deriving(Eq, Ord, ToStr)]
 pub struct DVec<N>
 {
   at: ~[N]
@@ -53,7 +53,7 @@ impl<N, Iter: Iterator<N>> FromIterator<N, Iter> for DVec<N>
 }
 
 // FIXME: is Clone needed?
-impl<N: Copy + DivisionRing + Algebraic + Clone + ApproxEq<N>> DVec<N>
+impl<N: Copy + DivisionRing + Algebraic + ApproxEq<N>> DVec<N>
 {
   pub fn canonical_basis_with_dim(dim: uint) -> ~[DVec<N>]
   {
@@ -87,7 +87,7 @@ impl<N: Copy + DivisionRing + Algebraic + Clone + ApproxEq<N>> DVec<N>
       if res.len() == dim - 1
       { break; }
 
-      let mut elt = basis_element.clone();
+      let mut elt = copy basis_element;
 
       elt = elt - self.scalar_mul(&basis_element.dot(self));
 
@@ -223,11 +223,11 @@ ScalarSub<N> for DVec<N>
   }
 }
 
-impl<N: Clone + Copy + Add<N, N> + Neg<N>> Translation<DVec<N>> for DVec<N>
+impl<N: Copy + Add<N, N> + Neg<N>> Translation<DVec<N>> for DVec<N>
 {
   #[inline]
   fn translation(&self) -> DVec<N>
-  { self.clone() }
+  { copy *self }
 
   #[inline]
   fn inv_translation(&self) -> DVec<N>
@@ -238,14 +238,14 @@ impl<N: Clone + Copy + Add<N, N> + Neg<N>> Translation<DVec<N>> for DVec<N>
   { *self = *self + *t; }
 }
 
-impl<N: Add<N, N> + Copy> Translatable<DVec<N>, DVec<N>> for DVec<N>
+impl<N: Add<N, N> + Neg<N> + Copy> Translatable<DVec<N>, DVec<N>> for DVec<N>
 {
   #[inline]
   fn translated(&self, t: &DVec<N>) -> DVec<N>
   { self + *t }
 }
 
-impl<N: Copy + DivisionRing + Algebraic + Clone>
+impl<N: Copy + DivisionRing + Algebraic>
 Norm<N> for DVec<N>
 {
   #[inline]
@@ -259,7 +259,7 @@ Norm<N> for DVec<N>
   #[inline]
   fn normalized(&self) -> DVec<N>
   {
-    let mut res : DVec<N> = self.clone();
+    let mut res : DVec<N> = copy *self;
 
     res.normalize();
 
diff --git a/src/vec_impl.rs b/src/vec_impl.rs
index 37f3902a..7902cacd 100644
--- a/src/vec_impl.rs
+++ b/src/vec_impl.rs
@@ -309,7 +309,7 @@ macro_rules! translation_impl(
 
 macro_rules! translatable_impl(
   ($t: ident) => (
-    impl<N: Add<N, N> + Copy> Translatable<$t<N>, $t<N>> for $t<N>
+    impl<N: Add<N, N> + Neg<N> + Copy> Translatable<$t<N>, $t<N>> for $t<N>
     {
       #[inline]
       fn translated(&self, t: &$t<N>) -> $t<N>