Fix compilation on Rust 1.15.x
@@ -1143,7 +1143,7 @@ fn deserialize_enum(
fn prepare_enum_variant_enum(
variants: &[Variant],
cattrs: &attr::Container,
-) -> (proc_macro2::TokenStream, Stmts) {
+) -> (TokenStream, Stmts) {
let variant_names_idents: Vec<_> = variants
.iter()
.enumerate()
