diff --git a/serde/src/lib.rs b/serde/src/lib.rs
index 6f53ed11..a8e9f96b 100644
--- a/serde/src/lib.rs
+++ b/serde/src/lib.rs
@@ -221,7 +221,7 @@ mod lib {
 // performed implicitly by the `?` operator or the standard library's `try!`
 // macro. This simplified macro gives a 5.5% improvement in compile time
 // compared to standard `try!`, and 9% improvement compared to `?`.
-#[allow(unused_macros)]
+#[cfg(not(no_serde_derive))]
 macro_rules! tri {
     ($expr:expr) => {
         match $expr {