diff --git a/src/Data/Type/Index/Quote.hs b/src/Data/Type/Index/Quote.hs
--- a/src/Data/Type/Index/Quote.hs
+++ b/src/Data/Type/Index/Quote.hs
@@ -27,7 +27,7 @@
 ix :: QuasiQuoter
 ix = QuasiQuoter
   { quoteExp  = parseIxExp
-  , quotePat  = error "ix: quotePat not defined"
+  , quotePat  = parseIxPat
   , quoteType = error "ix: quoteType not defined"
   , quoteDec  = error "ix: quoteDec not defined"
   }
@@ -45,4 +45,18 @@
   go = \case
     0 -> [| IZ |]
     n -> [| IS $(go $ n-1) |]
+
+parseIxPat :: String -> Q Pat
+parseIxPat s = maybe (fail $ "ix: couldn't parse Int: " ++ show s)
+  (notNeg >=> go)
+  $ readMaybe s
+  where
+  notNeg :: Int -> Q Int
+  notNeg n
+    | n < 0 = fail $ "ix: negative index: " ++ show n
+    | True  = return n
+  go :: Int -> Q Pat
+  go = \case
+    0 -> [p| IZ |]
+    n -> [p| IS $(go $ n-1) |]
 
diff --git a/type-combinators.cabal b/type-combinators.cabal
--- a/type-combinators.cabal
+++ b/type-combinators.cabal
@@ -1,5 +1,5 @@
 name: type-combinators
-version: 0.1.2.0
+version: 0.1.2.1
 category: Data
 synopsis: A collection of data types for type-level programming
 cabal-version: >=1.10