diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/parser/Lexer.x | 9 | ||||
| -rw-r--r-- | compiler/parser/Parser.y.pp | 17 |
2 files changed, 20 insertions, 6 deletions
diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x index 4a64069d73..95880946bb 100644 --- a/compiler/parser/Lexer.x +++ b/compiler/parser/Lexer.x @@ -57,6 +57,8 @@ module Lexer ( extension, bangPatEnabled, datatypeContextsEnabled, traditionalRecordSyntaxEnabled, typeLiteralsEnabled, + explicitForallEnabled, + inRulePrag, explicitNamespacesEnabled, sccProfilingOn, hpcEnabled, addWarning, lexTokenStream @@ -711,8 +713,7 @@ reservedSymsFM = listToUFM $ ,("∷", ITdcolon, unicodeSyntaxEnabled) ,("⇒", ITdarrow, unicodeSyntaxEnabled) - ,("∀", ITforall, \i -> unicodeSyntaxEnabled i && - explicitForallEnabled i) + ,("∀", ITforall, unicodeSyntaxEnabled) ,("→", ITrarrow, unicodeSyntaxEnabled) ,("←", ITlarrow, unicodeSyntaxEnabled) @@ -1931,8 +1932,8 @@ datatypeContextsEnabled :: Int -> Bool datatypeContextsEnabled flags = testBit flags datatypeContextsBit qqEnabled :: Int -> Bool qqEnabled flags = testBit flags qqBit --- inRulePrag :: Int -> Bool --- inRulePrag flags = testBit flags inRulePragBit +inRulePrag :: Int -> Bool +inRulePrag flags = testBit flags inRulePragBit rawTokenStreamEnabled :: Int -> Bool rawTokenStreamEnabled flags = testBit flags rawTokenStreamBit alternativeLayoutRule :: Int -> Bool diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp index 384fb537bf..9d087068bf 100644 --- a/compiler/parser/Parser.y.pp +++ b/compiler/parser/Parser.y.pp @@ -1050,7 +1050,8 @@ strict_mark :: { Located HsBang } -- A ctype is a for-all type ctype :: { LHsType RdrName } - : 'forall' tv_bndrs '.' ctype { LL $ mkExplicitHsForAllTy $2 (noLoc []) $4 } + : 'forall' tv_bndrs '.' ctype {% hintExplicitForall (getLoc $1) >> + return (LL $ mkExplicitHsForAllTy $2 (noLoc []) $4) } | context '=>' ctype { LL $ mkImplicitHsForAllTy $1 $3 } -- A type of form (context => type) is an *implicit* HsForAllTy | ipvar '::' type { LL (HsIParamTy (unLoc $1) $3) } @@ -1068,7 +1069,8 @@ ctype :: { LHsType RdrName } -- to 'field' or to 'Int'. So we must use `ctype` to describe the type. ctypedoc :: { LHsType RdrName } - : 'forall' tv_bndrs '.' ctypedoc { LL $ mkExplicitHsForAllTy $2 (noLoc []) $4 } + : 'forall' tv_bndrs '.' ctypedoc {% hintExplicitForall (getLoc $1) >> + return (LL $ mkExplicitHsForAllTy $2 (noLoc []) $4) } | context '=>' ctypedoc { LL $ mkImplicitHsForAllTy $1 $3 } -- A type of form (context => type) is an *implicit* HsForAllTy | ipvar '::' type { LL (HsIParamTy (unLoc $1) $3) } @@ -2240,4 +2242,15 @@ hintMultiWayIf span = do mwiEnabled <- liftM ((Opt_MultiWayIf `xopt`) . dflags) getPState unless mwiEnabled $ parseErrorSDoc span $ text "Multi-way if-expressions need -XMultiWayIf turned on" + +-- Hint about explicit-forall, assuming UnicodeSyntax is on +hintExplicitForall :: SrcSpan -> P () +hintExplicitForall span = do + forall <- extension explicitForallEnabled + rulePrag <- extension inRulePrag + unless (forall || rulePrag) $ parseErrorSDoc span $ vcat + [ text "Illegal symbol '∀' in type" + , text "Perhaps you intended -XRankNTypes or similar flag" + , text "to enable explicit-forall syntax: ∀ <tvs>. <type>" + ] } |