mkPrefixConPat, mkCharLitPat, mkNilPat,
- isBangHsBind, isBangLPat, hsPatNeedsParens,
+ isBangHsBind, isLiftedPatBind,
+ isBangLPat, hsPatNeedsParens,
isIrrefutableHsPat,
pprParendLPat
-- support hsPatType :: Pat Id -> Type
| VarPat id -- Variable
- | VarPatOut id TcEvBinds -- Used only for overloaded Ids; the
- -- bindings give its overloaded instances
| LazyPat (LPat id) -- Lazy pattern
| AsPat (Located id) (LPat id) -- As pattern
| ParPat (LPat id) -- Parenthesised pattern
pprPat :: (OutputableBndr name) => Pat name -> SDoc
pprPat (VarPat var) = pprPatBndr var
-pprPat (VarPatOut var bs) = pprPatBndr var <+> braces (ppr bs)
pprPat (WildPat _) = char '_'
pprPat (LazyPat pat) = char '~' <> pprParendLPat pat
pprPat (BangPat pat) = char '!' <> pprParendLPat pat
isBangLPat _ = False
isBangHsBind :: HsBind id -> Bool
--- In this module because HsPat is above HsBinds in the import graph
+-- A pattern binding with an outermost bang
+-- Defined in this module because HsPat is above HsBinds in the import graph
isBangHsBind (PatBind { pat_lhs = p }) = isBangLPat p
isBangHsBind _ = False
+isLiftedPatBind :: HsBind id -> Bool
+-- A pattern binding with a compound pattern, not just a variable
+-- (I# x) yes
+-- (# a, b #) no, even if a::Int#
+-- x no, even if x::Int#
+-- We want to warn about a missing bang-pattern on the yes's
+isLiftedPatBind (PatBind { pat_lhs = p }) = isLiftedLPat p
+isLiftedPatBind _ = False
+
+isLiftedLPat :: LPat id -> Bool
+isLiftedLPat (L _ (ParPat p)) = isLiftedLPat p
+isLiftedLPat (L _ (BangPat p)) = isLiftedLPat p
+isLiftedLPat (L _ (AsPat _ p)) = isLiftedLPat p
+isLiftedLPat (L _ (TuplePat _ Unboxed _)) = False
+isLiftedLPat (L _ (VarPat {})) = False
+isLiftedLPat (L _ (WildPat {})) = False
+isLiftedLPat _ = True
+
isIrrefutableHsPat :: OutputableBndr id => LPat id -> Bool
-- (isIrrefutableHsPat p) is true if matching against p cannot fail,
-- in the sense of falling through to the next pattern.
go1 (WildPat {}) = True
go1 (VarPat {}) = True
- go1 (VarPatOut {}) = True
go1 (LazyPat {}) = True
go1 (BangPat pat) = go pat
go1 (CoPat _ pat _) = go1 pat
hsPatNeedsParens :: Pat a -> Bool
hsPatNeedsParens (WildPat {}) = False
hsPatNeedsParens (VarPat {}) = False
-hsPatNeedsParens (VarPatOut {}) = True
hsPatNeedsParens (LazyPat {}) = False
hsPatNeedsParens (BangPat {}) = False
hsPatNeedsParens (CoPat {}) = True