A0-1-6: Add failing test case for alias templates

An alias template is an alias (e.g. a using statement) which is part of
a template, and is currently considered to be unused even if the
template is instantiated.

Author: lcartey

cpp/autosar/test/rules/A0-1-6/UnusedTypeDeclarations.expected

@@ -3,3 +3,6 @@
 | test.cpp:10:11:10:11 | D | Type declaration D is not used. |
 | test.cpp:74:11:74:11 | R | Type declaration R is not used. |
 | test.cpp:87:12:87:12 | struct <unnamed> | Type declaration struct <unnamed> is not used. |
+| test.cpp:104:26:104:26 | Y<int> | Type declaration Y<int> is not used. |
+| test.cpp:107:29:107:29 | Z | Type declaration Z is not used. |
+| test.cpp:108:29:108:30 | AA | Type declaration AA is not used. |

cpp/autosar/test/rules/A0-1-6/test.cpp

@@ -99,4 +99,14 @@ void test_nested_struct() {
 
 template <class T> class X { // COMPLIANT - template class never instantiated
   using custom_type = E<T>;  // COMPLIANT - template class never instantiated
-};
+};
+
+template <class T> class Y {}; // COMPLIANT[FALSE_POSITIVE] - used in the test case below
+
+// Alias templates
+template <typename T> using Z = Y<T>; // COMPLIANT[FALSE_POSITIVE] - used below
+template <typename T> using AA = Y<T>; // NON_COMPLIANT - never instantiated
+
+void test_alias_template() {
+  Z<int> v;
+}