diff --git a/xpcom/rust/xpcom/xpcom_macros/Cargo.toml b/xpcom/rust/xpcom/xpcom_macros/Cargo.toml
index 26f7d7b192a1..78238ae6d189 100644
--- a/xpcom/rust/xpcom/xpcom_macros/Cargo.toml
+++ b/xpcom/rust/xpcom/xpcom_macros/Cargo.toml
@@ -9,7 +9,7 @@ license = "MPL-2.0"
 proc-macro = true
 
 [dependencies]
-syn = "2"
+syn = { version = "2", features = ["full"] }
 quote = "1"
 proc-macro2 = "1"
 lazy_static = "1.0"