diff --git a/src/common/tvgArray.h b/src/common/tvgArray.h
index 8178bd0e..19c8f697 100644
--- a/src/common/tvgArray.h
+++ b/src/common/tvgArray.h
@@ -59,7 +59,7 @@ struct Array
         data[count++] = element;
     }
 
-    void push(Array<T>& rhs)
+    void push(const Array<T>& rhs)
     {
         if (rhs.count == 0) return;
         grow(rhs.count);
diff --git a/src/common/tvgInlist.h b/src/common/tvgInlist.h
index ff28cfd4..fc99ae3d 100644
--- a/src/common/tvgInlist.h
+++ b/src/common/tvgInlist.h
@@ -100,7 +100,7 @@ struct Inlist
         if (element == tail) tail = element->prev;
     }
 
-    bool empty()
+    bool empty() const
     {
         return head ? false : true;
     }