--- a/mfbt/SmallPointerArray.h
+++ b/mfbt/SmallPointerArray.h
@@ -176,17 +176,17 @@ public:
   const_iterator cend() const { return end(); }
 
 private:
   T** beginInternal() const {
     if (mInlineElements[0] || !mArray) {
       return const_cast<T**>(&mInlineElements[0]);
     }
 
-    if (!mArray->size()) {
+    if (mArray->empty()) {
       return nullptr;
     }
 
     return &(*mArray)[0];
   }
 
   // mArray and mInlineElements[1] share the same area in memory.
   //