--- a/xpcom/base/nsTraceRefcnt.cpp
+++ b/xpcom/base/nsTraceRefcnt.cpp
@@ -443,27 +443,22 @@ GetBloatEntry(const char* aTypeName, uin
 
       entry = new BloatEntry(aTypeName, aInstanceSize);
       PLHashEntry* e = PL_HashTableAdd(gBloatView, aTypeName, entry);
       if (!e) {
         delete entry;
         entry = nullptr;
       }
     } else {
-#ifdef DEBUG
-      static const char kMismatchedSizesMessage[] =
-        "Mismatched sizes were recorded in the memory leak logging table. "
-        "The usual cause of this is having a templated class that uses "
-        "MOZ_COUNT_{C,D}TOR in the constructor or destructor, respectively. "
-        "As a workaround, the MOZ_COUNT_{C,D}TOR calls can be moved to a "
-        "non-templated base class.";
-      NS_ASSERTION(aInstanceSize == 0 ||
-                   entry->GetClassSize() == aInstanceSize,
-                   kMismatchedSizesMessage);
-#endif // DEBUG
+      MOZ_ASSERT(aInstanceSize == 0 || entry->GetClassSize() == aInstanceSize,
+                 "Mismatched sizes were recorded in the memory leak logging table. "
+                 "The usual cause of this is having a templated class that uses "
+                 "MOZ_COUNT_{C,D}TOR in the constructor or destructor, respectively. "
+                 "As a workaround, the MOZ_COUNT_{C,D}TOR calls can be moved to a "
+                 "non-templated base class.");
     }
   }
   return entry;
 }
 
 static int
 DumpSerialNumbers(PLHashEntry* aHashEntry, int aIndex, void* aClosure)
 {