simplify_pat (VarPat id) = WildPat (idType id)
simplify_pat (VarPatOut id _) = WildPat (idType id) -- Ignore the bindings
simplify_pat (ParPat p) = unLoc (simplify_lpat p)
-simplify_pat (LazyPat p) = unLoc (simplify_lpat p)
+simplify_pat (LazyPat p) = WildPat (hsPatType p) -- For overlap and exhaustiveness checking
+ -- purposes, a ~pat is like a wildcard
simplify_pat (BangPat p) = unLoc (simplify_lpat p)
simplify_pat (AsPat id p) = unLoc (simplify_lpat p)
simplify_pat (SigPatOut p _) = unLoc (simplify_lpat p) -- I'm not sure this is right