diff --git a/src/classify/intproto.cpp b/src/classify/intproto.cpp
index 854026bc..f5f08cf1 100644
--- a/src/classify/intproto.cpp
+++ b/src/classify/intproto.cpp
@@ -511,7 +511,7 @@ INT_TEMPLATES_STRUCT *Classify::CreateIntTemplates(CLASSES FloatProtos,
     for (unsigned i = 0; i < fs_size; ++i) {
       fs.push_back(FClass->font_set[i]);
     }
-    IClass->font_set_id = this->fontset_table_.push_back(fs);
+    IClass->font_set_id = this->fontset_table_.push_back(std::move(fs));
     AddIntClass(IntTemplates, ClassId, IClass);
 
     for (ProtoId = 0; ProtoId < FClass->NumProtos; ProtoId++) {