Derive Debug for Ident/Span

Now that under the hood they implement Debug
diff --git a/src/ident.rs b/src/ident.rs
index dcd8dd1..181bac9 100644
--- a/src/ident.rs
+++ b/src/ident.rs
@@ -8,7 +8,7 @@
 use Span;
 use tokens;
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct Ident {
     pub sym: Symbol,
     pub span: Span,
@@ -77,12 +77,6 @@
     }
 }
 
-impl fmt::Debug for Ident {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Debug::fmt(self.sym.as_str(), formatter)
-    }
-}
-
 impl<T: ?Sized> PartialEq<T> for Ident
     where T: AsRef<str>
 {
diff --git a/synom/src/span.rs b/synom/src/span.rs
index a652c41..933d4c3 100644
--- a/synom/src/span.rs
+++ b/synom/src/span.rs
@@ -1,9 +1,8 @@
 use std::hash::{Hash, Hasher};
-use std::fmt;
 
 use proc_macro2;
 
-#[derive(Clone, Copy, Default)]
+#[derive(Clone, Copy, Default, Debug)]
 pub struct Span(pub proc_macro2::Span);
 
 impl PartialEq for Span {
@@ -18,10 +17,3 @@
     fn hash<H: Hasher>(&self, _hasher: &mut H) {
     }
 }
-
-impl fmt::Debug for Span {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("Span")
-         .finish()
-    }
-}