diff --git a/src/matrix.rs b/src/matrix.rs
index f364072..aa1aaf2 100644
--- a/src/matrix.rs
+++ b/src/matrix.rs
@@ -100,15 +100,6 @@ impl<S: BaseFloat> Matrix2<S> {
     }
 }
 
-impl<S: Copy + Neg<Output = S>> Matrix2<S> {
-    /// Negate this `Matrix2` in-place.
-    #[inline]
-    pub fn neg_self(&mut self) {
-        self[0].neg_self();
-        self[1].neg_self();
-    }
-}
-
 impl<S: BaseFloat> Matrix3<S> {
     /// Create a new matrix, providing values for each index.
     #[inline]
@@ -200,16 +191,6 @@ impl<S: BaseFloat> Matrix3<S> {
     }
 }
 
-impl<S: Copy + Neg<Output = S>> Matrix3<S> {
-    /// Negate this `Matrix3` in-place.
-    #[inline]
-    pub fn neg_self(&mut self) {
-        self[0].neg_self();
-        self[1].neg_self();
-        self[2].neg_self();
-    }
-}
-
 impl<S: BaseFloat> Matrix4<S> {
     /// Create a new matrix, providing values for each index.
     #[inline]
@@ -267,17 +248,6 @@ impl<S: BaseFloat> Matrix4<S> {
     }
 }
 
-impl<S: Copy + Neg<Output = S>> Matrix4<S> {
-    /// Negate this `Matrix4` in-place.
-    #[inline]
-    pub fn neg_self(&mut self) {
-        self[0].neg_self();
-        self[1].neg_self();
-        self[2].neg_self();
-        self[3].neg_self();
-    }
-}
-
 /// A column-major matrix of arbitrary dimensions.
 pub trait Matrix  where
     // FIXME: Ugly type signatures - blocked by rust-lang/rust#24092
diff --git a/src/vector.rs b/src/vector.rs
index 6b8a80e..8d5682c 100644
--- a/src/vector.rs
+++ b/src/vector.rs
@@ -216,14 +216,6 @@ macro_rules! impl_vector {
             }
         }
 
-        impl<$S: Copy + Neg<Output = $S>> $VectorN<$S> {
-            /// Negate this vector in-place (multiply by -1).
-            #[inline]
-            pub fn neg_self(&mut self) {
-                $(self.$field = -self.$field);+
-            }
-        }
-
         /// The short constructor.
         #[inline]
         pub fn $constructor<S>($($field: S),+) -> $VectorN<S> {