Fix Column implementation generating an ICE.

src/mat_impl.rs

@@ -84,7 +84,7 @@ macro_rules! column_impl(
           if i == Dim::dim::<$t<N>>()
           { break }
 
-          self.at((i, col)) = copy *e;
+          self.set((i, col), copy *e);
         }
       }
 

src/tests/mat.rs

@@ -9,6 +9,10 @@ use traits::inv::Inv;
 #[test]
 use traits::rotation::{Rotation, Rotatable};
 #[test]
+use traits::indexable::Indexable;
+#[test]
+use traits::transpose::Transpose;
+#[test]
 use vec::Vec1;
 #[test]
 use mat::{Mat1, Mat2, Mat3};
@@ -54,3 +58,11 @@ fn test_rotation2()
     assert!(randmat.rotated(ang).rotation().approx_eq(ang));
   }
 }
+
+#[test]
+fn test_index_mat2()
+{
+  let mat: Mat2<f64> = random();
+
+  assert!(mat.at((0, 1)) == mat.transposed().at((1, 0)));
+}