diff --git a/src/unstable.rs b/src/unstable.rs
index 916ac46..a3ce1fd 100644
--- a/src/unstable.rs
+++ b/src/unstable.rs
@@ -159,7 +159,7 @@
     }
 }
 
-#[derive(Copy, Clone, Default)]
+#[derive(Copy, Clone)]
 pub struct Span(proc_macro::Span);
 
 impl Span {
@@ -168,6 +168,12 @@
     }
 }
 
+impl Default for Span {
+    fn default() -> Span {
+        Span(proc_macro::Span::def_site())
+    }
+}
+
 impl fmt::Debug for Span {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         self.0.fmt(f)