check :: [EquationInfo] -> ([ExhaustivePat], [EquationInfo])
-- Second result is the shadowed equations
-check qs = (untidy_warns, shadowed_eqns)
+ -- if there are view patterns, just give up - don't know what the function is
+check qs | has_view_pattern = ([],[])
+ | otherwise = (untidy_warns, shadowed_eqns)
where
+ is_view x = hasViewPat x
+ has_view_pattern = any (\(EqnInfo p _) -> any is_view p) qs
(warns, used_nos) = check' ([1..] `zip` map simplify_eqn qs)
untidy_warns = map untidy_exhaustive warns
shadowed_eqns = [eqn | (eqn,i) <- qs `zip` [1..],
| literals = split_by_literals qs
| constructors = split_by_constructor qs
| only_vars = first_column_only_vars qs
--- FIXME: hack to get view patterns through for now
- | otherwise = ([([],[])],emptyUniqSet)
-- pprPanic "Check.check': Not implemented :-(" (ppr first_pats)
where
-- Note: RecPats will have been simplified to ConPats
isBangHsBind, hsPatNeedsParens,
patsAreAllCons, isConPat, isSigPat, isWildPat,
- patsAreAllLits, isLitPat, isIrrefutableHsPat
+ patsAreAllLits, isLitPat, isIrrefutableHsPat, hasViewPat
) where
import {-# SOURCE #-} HsExpr (SyntaxExpr, LHsExpr, pprLExpr)
The 1.3 report defines what ``irrefutable'' and ``failure-free'' patterns are.
\begin{code}
+hasViewPat :: Pat id -> Bool
+hasViewPat p = hasViewPat' (L undefined p)
+
+hasViewPat' :: LPat id -> Bool
+hasViewPat' (L _ p) = go p where
+ go (WildPat _) = False
+ go (VarPat _) = False
+ go (VarPatOut _ _) = False
+ go (LazyPat p) = hasViewPat' p
+ go (AsPat _ p) = hasViewPat' p
+ go (ParPat p) = hasViewPat' p
+ go (BangPat p) = hasViewPat' p
+ go (ListPat p _) = any hasViewPat' p
+ go (TuplePat p _ _) = any hasViewPat' p
+ go (PArrPat p _) = any hasViewPat' p
+ go (ConPatIn _ p) = go' p
+ go (ConPatOut _ _ _ _ p _) = go' p
+ go (ViewPat _ _ _) = True
+ go (QuasiQuotePat _) = False
+ go (LitPat _) = False
+ go (NPat _ _ _) = False
+ go (NPlusKPat _ _ _ _) = False
+ go (TypePat _) = False
+ go (SigPatIn p _) = hasViewPat' p
+ go (SigPatOut p _) = hasViewPat' p
+ go (CoPat _ _ _) = False
+ go' p = case p of
+ PrefixCon ps -> any hasViewPat' ps
+ RecCon (HsRecFields fs _) -> any (hasViewPat' . hsRecFieldArg) fs
+ InfixCon p1 p2 -> hasViewPat' p1 || hasViewPat' p2
+
isWildPat :: Pat id -> Bool
isWildPat (WildPat _) = True
isWildPat _ = False