Activate the unused_results lint.

src/lib.rs

@@ -102,6 +102,7 @@ Feel free to add your project to this list if you happen to use **nalgebra**!
 #[deny(unnecessary_parens)];
 #[deny(non_uppercase_statics)];
 #[deny(unnecessary_qualification)];
+#[deny(unused_result)];
 #[warn(missing_doc)];
 #[feature(macro_rules)];
 #[doc(html_root_url = "http://www.rust-ci.org/sebcrozet/nalgebra/doc")];

src/structs/dvec.rs

@@ -299,7 +299,7 @@ impl<N: Num + Real + Clone> Norm<N> for DVec<N> {
     fn normalize_cpy(v: &DVec<N>) -> DVec<N> {
         let mut res : DVec<N> = v.clone();
 
-        res.normalize();
+        let _ = res.normalize();
 
         res
     }

src/structs/vec_macros.rs

@@ -448,7 +448,7 @@ macro_rules! norm_impl(
             fn normalize_cpy(v: &$t<N>) -> $t<N> {
                 let mut res : $t<N> = v.clone();
 
-                res.normalize();
+                let _ = res.normalize();
 
                 res
             }