diff --git a/src/config/Property.h b/src/config/Property.h
index 3a46288..f71f49e 100644
--- a/src/config/Property.h
+++ b/src/config/Property.h
@@ -49,7 +49,7 @@ namespace Feather
         T GetValue() { return value; }
 
         // Property<T> can be automatically cast to T
-        operator T() const { return value; }
+        inline operator T() const { return value; }
 
         inline string ToString() const { return std::to_string(value); }