diff --git a/derive/Cargo.toml b/derive/Cargo.toml
index e3e0f39..8bbe64f 100644
--- a/derive/Cargo.toml
+++ b/derive/Cargo.toml
@@ -15,7 +15,8 @@ name = "bytemuck_derive"
 proc-macro = true
 
 [dependencies]
-syn = "1"
+# syn seems to have broken backwards compability in this version https://github.com/dtolnay/syn/issues/1194
+syn = "1.0.15"
 quote = "1"
 proc-macro2 = "1"