Issue an error if two dynSeries objects with common variable names are...

Issue an error if two dynSeries objects with common variable names are concatenated. Added a unitary test.

matlab/@dynSeries/horzcat.m

@@ -237,3 +237,27 @@ end
 %$ t(4) = dyn_assert(ts4.name,e.name);
 %$ T = all(t);
 %@eof:5
+
+%@test:6
+%$ % Define a data set.
+%$ A = [transpose(1:10),2*transpose(1:10)];
+%$ B = [transpose(1:10),2*transpose(1:10)];
+%$
+%$ % Define names
+%$ A_name = {'A1';'A2'};
+%$ B_name = {'B1';'A2'};
+%$
+%$ % Instantiate two time series objects.
+%$ ts1 = dynSeries(A,[],A_name,[]);
+%$ ts2 = dynSeries(B,[],B_name,[]);
+%$
+%$ % Call the tested method.
+%$ try
+%$   ts3 = [ts1,ts2];
+%$   t = 0;
+%$ catch
+%$   t = 1;
+%$ end
+%$
+%$ T = t;
+%@eof:6

matlab/@dynSeries/private/horzcat2.m

@@ -55,7 +55,12 @@ function a = horzcat2(b,c)
 %
 % You should have received a copy of the GNU General Public License
 % along with Dynare.  If not, see <http://www.gnu.org/licenses/>.
-  
+
+[n,message] = common_strings_in_cell_arrays(b.name,c.name);
+if n
+    error(['dynSeries::horzcat: I cannot concatenate dynSeries objects with common variable names (' message ')!'])
+end
+    
 if b.freq ~= c.freq
     error('dynSeries::horzcat: All time series objects must have common frequency!')
 else