--- Unpack string patterns fully, so we can see when they overlap with
--- each other, or even explicit lists of Chars.
-tidy_pat (LitPat lit)
+tidy_pat (NPat lit mb_neg eq) = tidyNPat tidy_lit_pat lit mb_neg eq
+tidy_pat (LitPat lit) = tidy_lit_pat lit
+
+tidy_lit_pat :: HsLit -> Pat Id
+-- Unpack string patterns fully, so we can see when they
+-- overlap with each other, or even explicit lists of Chars.
+tidy_lit_pat lit