diff --git a/similarity_search/src/method/small_world_rand.cc b/similarity_search/src/method/small_world_rand.cc
index c7eb4e4..dc5c04a 100644
--- a/similarity_search/src/method/small_world_rand.cc
+++ b/similarity_search/src/method/small_world_rand.cc
@@ -601,7 +601,7 @@ void SmallWorldRand<dist_t>::addCriticalSection(MSWNode *newElement){
 template <typename dist_t>
 void SmallWorldRand<dist_t>::Search(RangeQuery<dist_t>* query, IdType) const {
 //  throw runtime_error("Range search is not supported!");
-    CHECK_MSG(1=0, "Search");
+    CHECK_MSG(1==0, "Search");
     std::out<< "search" << endl;
     if (searchAlgoType_ == kV1Merge) {std::cerr << "call SearchV1Merge" << endl; SearchV1Merge(query);}
     else {std::cerr << "call SearchOld" << endl; SearchOld(query);}