diff options
Diffstat (limited to 'libraries')
| -rw-r--r-- | libraries/template-haskell/Language/Haskell/TH/Ppr.hs | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/libraries/template-haskell/Language/Haskell/TH/Ppr.hs b/libraries/template-haskell/Language/Haskell/TH/Ppr.hs index ef9a718111..d2e1855da2 100644 --- a/libraries/template-haskell/Language/Haskell/TH/Ppr.hs +++ b/libraries/template-haskell/Language/Haskell/TH/Ppr.hs @@ -791,12 +791,17 @@ instance Ppr Type where -- Works, in a degenerate way, for SigT, and puts parens round (ty :: kind) -- See Note [Pretty-printing kind signatures] instance Ppr TypeArg where - ppr (TANormal ty) = ppr ty - ppr (TyArg ki) = char '@' <> ppr ki + ppr (TANormal ty) = parensIf (isStarT ty) (ppr ty) + ppr (TyArg ki) = char '@' <> parensIf (isStarT ki) (ppr ki) pprParendTypeArg :: TypeArg -> Doc -pprParendTypeArg (TANormal ty) = pprParendType ty -pprParendTypeArg (TyArg ki) = char '@' <> pprParendType ki +pprParendTypeArg (TANormal ty) = parensIf (isStarT ty) (pprParendType ty) +pprParendTypeArg (TyArg ki) = char '@' <> parensIf (isStarT ki) (pprParendType ki) + +isStarT :: Type -> Bool +isStarT StarT = True +isStarT _ = False + {- Note [Pretty-printing kind signatures] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GHC's parser only recognises a kind signature in a type when there are @@ -810,18 +815,20 @@ pprTyApp (ArrowT, [TANormal arg1, TANormal arg2]) = sep [pprFunArgType arg1 <+> pprTyApp (EqualityT, [TANormal arg1, TANormal arg2]) = sep [pprFunArgType arg1 <+> text "~", ppr arg2] pprTyApp (ListT, [TANormal arg]) = brackets (ppr arg) +pprTyApp (TupleT 1, args) = pprTyApp (ConT (tupleTypeName 1), args) +pprTyApp (PromotedTupleT 1, args) = pprTyApp (PromotedT (tupleDataName 1), args) pprTyApp (TupleT n, args) - | length args == n - = if n == 1 - then pprTyApp (ConT (tupleTypeName 1), args) - else parens (commaSep args) + | length args == n, Just args' <- traverse fromTANormal args + = parens (commaSep args') pprTyApp (PromotedTupleT n, args) - | length args == n - = if n == 1 - then pprTyApp (PromotedT (tupleDataName 1), args) - else quoteParens (commaSep args) + | length args == n, Just args' <- traverse fromTANormal args + = quoteParens (commaSep args') pprTyApp (fun, args) = pprParendType fun <+> sep (map pprParendTypeArg args) +fromTANormal :: TypeArg -> Maybe Type +fromTANormal (TANormal arg) = Just arg +fromTANormal (TyArg _) = Nothing + pprFunArgType :: Type -> Doc -- Should really use a precedence argument -- Everything except forall and (->) binds more tightly than (->) pprFunArgType ty@(ForallT {}) = parens (ppr ty) |