diff --git a/src/lib.rs b/src/lib.rs
index 7a2f5b6..571ecf6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -18,7 +18,7 @@
 #[cfg(feature = "unstable")]
 mod imp;
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct TokenStream(imp::TokenStream);
 
 #[derive(Debug)]
@@ -84,7 +84,7 @@
     }
 }
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub struct Span(imp::Span);
 
 impl Default for Span {
@@ -99,7 +99,7 @@
     }
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct TokenTree {
     pub span: Span,
     pub kind: TokenKind,
@@ -111,7 +111,7 @@
     }
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub enum TokenKind {
     Sequence(Delimiter, TokenStream),
     Word(Symbol),
@@ -119,7 +119,7 @@
     Literal(Literal),
 }
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub enum Delimiter {
     Parenthesis,
     Brace,
@@ -127,7 +127,7 @@
     None,
 }
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub struct Symbol(imp::Symbol);
 
 impl<'a> From<&'a str> for Symbol {
@@ -148,13 +148,13 @@
     }
 }
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub enum OpKind {
     Alone,
     Joint,
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct Literal(imp::Literal);
 
 impl fmt::Display for Literal {
@@ -209,6 +209,7 @@
     f32, f64, char, &'a str,
 }
 
+#[derive(Debug)]
 pub struct TokenIter(imp::TokenIter);
 
 impl Iterator for TokenIter {
diff --git a/src/stable.rs b/src/stable.rs
index 042816a..bfc3dc1 100644
--- a/src/stable.rs
+++ b/src/stable.rs
@@ -15,7 +15,7 @@
 
 use {TokenTree, TokenKind, Delimiter, OpKind};
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct TokenStream {
     inner: Vec<TokenTree>,
 }
@@ -136,7 +136,7 @@
     }
 }
 
-#[derive(Clone, Copy, Default)]
+#[derive(Clone, Copy, Default, Debug)]
 pub struct Span;
 
 impl Span {
@@ -145,7 +145,7 @@
     }
 }
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub struct Symbol(usize);
 
 thread_local!(static SYMBOLS: RefCell<Interner> = RefCell::new(Interner::new()));
@@ -207,7 +207,7 @@
    }
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct Literal(String);
 
 impl Literal {
@@ -821,6 +821,8 @@
         |
         tag!("i64") => { |_| () }
         |
+        tag!("i128") => { |_| () }
+        |
         tag!("usize") => { |_| () }
         |
         tag!("u8") => { |_| () }
@@ -831,6 +833,8 @@
         |
         tag!("u64") => { |_| () }
         |
+        tag!("u128") => { |_| () }
+        |
         epsilon!()
     ) >>
     (())
@@ -850,7 +854,6 @@
         10
     };
 
-    let mut value = 0u64;
     let mut len = 0;
     let mut empty = true;
     for b in input.bytes() {
@@ -870,14 +873,6 @@
         if digit >= base {
             return IResult::Error;
         }
-        value = match value.checked_mul(base) {
-            Some(value) => value,
-            None => return IResult::Error,
-        };
-        value = match value.checked_add(digit) {
-            Some(value) => value,
-            None => return IResult::Error,
-        };
         len += 1;
         empty = false;
     }
@@ -1087,6 +1082,7 @@
             8u8
             9
             0
+            0xffffffffffffffffffffffffffffffff
         ");
     }
 }