X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FhsSyn%2FHsPat.lhs;h=1098ff03b249ac38b1d9f84dcab58be5fa3c6164;hb=e4a77504c3c5c39eeec191006cb11000b18c2d15;hp=fe3003d9093c37afd3f2f65553a8d137cae3ae03;hpb=faca1a62c1385aa6ebdeb7d25ffa193ba2283fb9;p=ghc-hetmet.git

diff --git a/compiler/hsSyn/HsPat.lhs b/compiler/hsSyn/HsPat.lhs
index fe3003d..1098ff0 100644
--- a/compiler/hsSyn/HsPat.lhs
+++ b/compiler/hsSyn/HsPat.lhs
@@ -22,8 +22,9 @@ module HsPat (
 
 	mkPrefixConPat, mkCharLitPat, mkNilPat, 
 
-	isBangHsBind, isBangLPat, hsPatNeedsParens,
-	isIrrefutableHsPat,
+        isBangHsBind, isLiftedPatBind,
+        isBangLPat, hsPatNeedsParens,
+        isIrrefutableHsPat,
 
 	pprParendLPat
     ) where
@@ -64,7 +65,7 @@ data Pat id
 	-- support hsPatType :: Pat Id -> Type
 
   | VarPat	id			-- Variable
-  | LazyPat	(LPat id)		-- Lazy pattern
+  | LazyPat     (LPat id)               -- Lazy pattern
   | AsPat	(Located id) (LPat id)  -- As pattern
   | ParPat      (LPat id)		-- Parenthesised pattern
   | BangPat	(LPat id)		-- Bang pattern
@@ -121,7 +122,9 @@ data Pat id
   | LitPat	    HsLit		-- Used for *non-overloaded* literal patterns:
 					-- Int#, Char#, Int, Char, String, etc.
 
-  | NPat	    (HsOverLit id)		-- ALWAYS positive
+  | NPat		-- Used for all overloaded literals, 
+    			-- including overloaded strings with -XOverloadedStrings
+                    (HsOverLit id)		-- ALWAYS positive
 		    (Maybe (SyntaxExpr id))	-- Just (Name of 'negate') for negative
 						-- patterns, Nothing otherwise
 		    (SyntaxExpr id)		-- Equality checker, of type t->t->Bool
@@ -374,10 +377,29 @@ isBangLPat (L _ (ParPat p))   = isBangLPat p
 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.