diff --git a/include/sdsl/dac_vector.hpp b/include/sdsl/dac_vector.hpp
index bcbbda3c..c2004c66 100644
--- a/include/sdsl/dac_vector.hpp
+++ b/include/sdsl/dac_vector.hpp
@@ -153,7 +153,7 @@ class dac_vector_dp
             this->swap(other);
         }
 
-        dac_vector_dp& operator=(dac_vector_dp other) {
+        dac_vector_dp& operator=(dac_vector_dp&& other) {
             this->swap(other);
             return *this;
         }
@@ -218,7 +218,7 @@ class dac_vector_dp
                 lvl--;
                 bit_sizes.push_back(b);
             }
-            assert(bit_sizes.size() <= max_levels);
+            assert(bit_sizes.size() <= (unsigned int)max_levels);
 
             size_t total_overflow_size = 0;
             for (size_t i = 0; i < c.size(); ++i) {