Parse generic params on impl block
diff --git a/syntax/mod.rs b/syntax/mod.rs
index 9a21087..1dcb55c 100644
--- a/syntax/mod.rs
+++ b/syntax/mod.rs
@@ -136,6 +136,7 @@
 
 pub struct Impl {
     pub impl_token: Token![impl],
+    pub generics: Lifetimes,
     pub negative: bool,
     pub ty: Type,
     pub brace_token: Brace,