diff --git a/proc_macro/Cargo.toml b/proc_macro/Cargo.toml
index b5ac2b5..e9aab38 100644
--- a/proc_macro/Cargo.toml
+++ b/proc_macro/Cargo.toml
@@ -12,5 +12,5 @@ proc-macro = true
 [dependencies]
 quote = "1"
 proc-macro2 = "1.0.66"
-syn = { version = "1.0", features = ["full"] }
+syn = { version = "2.0.66", features = ["full"] }