Use proc-macro2's Span instead of our own
diff --git a/tests/test_grouping.rs b/tests/test_grouping.rs
index f548947..a4b332e 100644
--- a/tests/test_grouping.rs
+++ b/tests/test_grouping.rs
@@ -26,7 +26,7 @@
 fn lit<T: Into<Literal>>(t: T) -> Expr {
     expr(Lit {
         value: LitKind::Other(t.into()),
-        span: syn::Span::default(),
+        span: Span::default(),
     })
 }