Add an error check after calling doexpr2().

sourcepawn/compiler/sc1.cpp

@@ -2207,6 +2207,17 @@ static void declloc(int tokid)
               &child, 0, &val);
             pushreg(sPRI);
             
+            switch (ident) {
+              case iVARIABLE:
+              case iEXPRESSION:
+              case iARRAYCELL:
+              case iCONSTEXPR:
+                break;
+              default:
+                error(29);
+                break;
+            }
+
             if (!needtoken(']'))
               break;
           }