Resolve some warnings about incomplete patterns

Author: Lysxia

src/Test/StrictCheck/Produce.hs

@@ -167,9 +167,9 @@ draws inputs = go [inputs]
     pick :: [a] -> Gen (a, [a])
     pick as = do
       index <- choose (0, length as - 1)
-      let (before, picked : after) = splitAt index as
-      return (picked, before ++ after)
-
+      case splitAt index as of
+        (before, picked : after) -> return (picked, before ++ after)
+        _ -> error "pick: empty list"
 
 
 ---------------------------------------------

src/Test/StrictCheck/TH.hs

@@ -75,13 +75,13 @@ constructor2PatternDec ty idx (NormalC conName argTypes) = do
 constructor2PatternDec ty idx (InfixC argType1 conName argType2) = do
   let argTypes = [argType1, argType2]
   (npPat, names) <- productPattern (map snd argTypes)
-  when (length names /= 2) $
-    reportError "The impossible happened: Infix Pattern have more than 2 binders"
-  let nm1 : nm2 : _ = names
-  return
-    ( PatSynSigD patDecName (patternTypeDec (map snd argTypes) ty),
-      infixPatternDec idx patDecName nm1 nm2 npPat
-    )
+  case names of
+    nm1 : nm2 : _ ->
+      return
+        ( PatSynSigD patDecName (patternTypeDec (map snd argTypes) ty),
+          infixPatternDec idx patDecName nm1 nm2 npPat
+        )
+    _ -> reportError "The impossible happened: Infix Pattern have more than 2 binders"
   where
     patDecName = mkName (nameBase conName ++ "%")
 constructor2PatternDec _ _ _ =