diff --git a/src/structs/dmat.rs b/src/structs/dmat.rs
index 6b66bb29..e66d1edb 100644
--- a/src/structs/dmat.rs
+++ b/src/structs/dmat.rs
@@ -2,8 +2,8 @@
 
 #![allow(missing_doc)] // we hide doc to not have to document the $trhs double dispatch trait.
 
-use rand::Rand;
-use rand;
+use std::rand::Rand;
+use std::rand;
 use std::num::{One, Zero};
 use traits::operations::ApproxEq;
 use std::mem;
diff --git a/src/structs/dvec.rs b/src/structs/dvec.rs
index 2781b7f9..a5200dfa 100644
--- a/src/structs/dvec.rs
+++ b/src/structs/dvec.rs
@@ -3,8 +3,8 @@
 #![allow(missing_doc)] // we hide doc to not have to document the $trhs double dispatch trait.
 
 use std::num::{Zero, One, Float};
-use rand::Rand;
-use rand;
+use std::rand::Rand;
+use std::rand;
 use std::slice::{Items, MutItems};
 use traits::operations::ApproxEq;
 use std::iter::FromIterator;
diff --git a/src/structs/spec/mat.rs b/src/structs/spec/mat.rs
index ccd307c2..e44c2e06 100644
--- a/src/structs/spec/mat.rs
+++ b/src/structs/spec/mat.rs
@@ -122,7 +122,7 @@ impl<N: Clone> Row<Vec3<N>> for Mat3<N> {
             0 => Vec3::new(self.m11.clone(), self.m12.clone(), self.m13.clone()),
             1 => Vec3::new(self.m21.clone(), self.m22.clone(), self.m23.clone()),
             2 => Vec3::new(self.m31.clone(), self.m32.clone(), self.m33.clone()),
-            _ => fail!("Index out of range: 3d matrices do not have " + i.to_str() + " rows.")
+            _ => fail!("Index out of range: 3d matrices do not have {} rows.",  i.to_str())
         }
     }
 
@@ -144,7 +144,7 @@ impl<N: Clone> Row<Vec3<N>> for Mat3<N> {
                 self.m32 = r.y.clone();
                 self.m33 = r.z;
             },
-            _ => fail!("Index out of range: 3d matrices do not have " + i.to_str() + " rows.")
+            _ => fail!("Index out of range: 3d matrices do not have {} rows.",  i.to_str())
 
         }
     }
@@ -162,7 +162,7 @@ impl<N: Clone> Col<Vec3<N>> for Mat3<N> {
             0 => Vec3::new(self.m11.clone(), self.m21.clone(), self.m31.clone()),
             1 => Vec3::new(self.m12.clone(), self.m22.clone(), self.m32.clone()),
             2 => Vec3::new(self.m13.clone(), self.m23.clone(), self.m33.clone()),
-            _ => fail!("Index out of range: 3d matrices do not have " + i.to_str() + " cols.")
+            _ => fail!("Index out of range: 3d matrices do not have {} cols.", i.to_str() )
         }
     }
 
@@ -184,7 +184,7 @@ impl<N: Clone> Col<Vec3<N>> for Mat3<N> {
                 self.m23 = r.y.clone();
                 self.m33 = r.z;
             },
-            _ => fail!("Index out of range: 3d matrices do not have " + i.to_str() + " cols.")
+            _ => fail!("Index out of range: 3d matrices do not have {} cols.", i.to_str() )
 
         }
     }
diff --git a/src/structs/spec/vec.rs b/src/structs/spec/vec.rs
index 5b747808..1ab7ef13 100644
--- a/src/structs/spec/vec.rs
+++ b/src/structs/spec/vec.rs
@@ -53,7 +53,7 @@ impl<N: Clone> Row<Vec1<N>> for Vec2<N> {
         match i {
             0 => Vec1::new(self.x.clone()),
             1 => Vec1::new(self.y.clone()),
-            _ => fail!("Index out of range: 2d vectors do not have " + i.to_str() + " rows.")
+            _ => fail!("Index out of range: 2d vectors do not have {} rows. ", i.to_str())
         }
     }
 
@@ -62,7 +62,7 @@ impl<N: Clone> Row<Vec1<N>> for Vec2<N> {
         match i {
             0 => self.x = r.x,
             1 => self.y = r.x,
-            _ => fail!("Index out of range: 2d vectors do not have " + i.to_str() + " rows.")
+            _ => fail!("Index out of range: 2d vectors do not have {} rows.", i.to_str())
 
         }
     }