disallow passing pointer to utils::as_const() as it does nothing

Author: firewave

lib/utils.h

@@ -419,6 +419,7 @@ namespace utils {
     constexpr typename std::add_const<T>::type & as_const(T& t) noexcept
     {
         static_assert(!std::is_const<T>::value, "object is already const");
+        static_assert(!std::is_pointer<T>::value, "object is a pointer");
         // NOLINTNEXTLINE(bugprone-return-const-ref-from-parameter) - potential false positive
         return t;
     }

test/testutils.cpp

@@ -542,10 +542,9 @@ class TestUtils : public TestFixture {
             ASSERT(c.written);
         }
         {
-            C c;
-            C* cp = &c;
-            utils::as_const(cp)->f(); // (correctly) calls non-const version
-            ASSERT(c.written);
+            int i;
+            auto cr = utils::as_const(i); // TODO: does nothing and should not be allowed
+            (void)cr;
         }
     }