diff --git a/tools/libclang/CXCursor.cpp b/tools/libclang/CXCursor.cpp
index b5682055b9e3851c7af918e2eae6e62c081575ad..2cdb71bb02245253ad86efe5fe03f74da3a514c9 100644
--- a/tools/libclang/CXCursor.cpp
+++ b/tools/libclang/CXCursor.cpp
@@ -1045,7 +1045,7 @@ unsigned clang_CXCursorSet_contains(CXCursorSet set, CXCursor cursor) {
   CXCursorSet_Impl *setImpl = unpackCXCursorSet(set);
   if (!setImpl)
     return 0;
-  return setImpl->find(cursor) == setImpl->end();
+  return setImpl->find(cursor) != setImpl->end();
 }
 
 unsigned clang_CXCursorSet_insert(CXCursorSet set, CXCursor cursor) {