diff options
Diffstat (limited to 'compiler/GHC/Types/Hint/Ppr.hs')
| -rw-r--r-- | compiler/GHC/Types/Hint/Ppr.hs | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/compiler/GHC/Types/Hint/Ppr.hs b/compiler/GHC/Types/Hint/Ppr.hs index eb68ff0c33..6651fbd2e3 100644 --- a/compiler/GHC/Types/Hint/Ppr.hs +++ b/compiler/GHC/Types/Hint/Ppr.hs @@ -18,6 +18,7 @@ import GHC.Unit.Types import GHC.Utils.Outputable import Data.List (intersperse) +import qualified Data.List.NonEmpty as NE instance Outputable GhcHint where ppr = \case @@ -63,8 +64,19 @@ instance Outputable GhcHint where -> text "Use parentheses." SuggestIncreaseMaxPmCheckModels -> text "Increase the limit or resolve the warnings to suppress this message." - SuggestAddTypeSignature - -> text "Add a type signature." + SuggestAddTypeSignatures bindings + -> case bindings of + -- This might happen when we have bindings which are /too complicated/, + -- see for example 'DsCannotMixPolyAndUnliftedBindings' in 'GHC.HsToCore.Errors.Types'. + -- In this case, we emit a generic message. + UnnamedBinding -> text "Add a type signature." + NamedBindings (x NE.:| xs) -> + let nameList = case xs of + [] -> quotes . ppr $ x + _ -> pprWithCommas (quotes . ppr) xs <+> text "and" <+> quotes (ppr x) + in hsep [ text "Consider giving" + , nameList + , text "a type signature"] SuggestBindToWildcard rhs -> hang (text "Suppress this warning by saying") 2 (quotes $ text "_ <-" <+> ppr rhs) SuggestAddInlineOrNoInlinePragma lhs_id rule_act @@ -104,6 +116,10 @@ instance Outputable GhcHint where in case mb_mod of Nothing -> header <+> text "the hsig file." Just mod -> header <+> ppr (moduleName mod) <> text "'s hsig file." + SuggestFixOrphanInstance + -> vcat [ text "Move the instance declaration to the module of the class or of the type, or" + , text "wrap the type with a newtype and declare the instance on the new type." + ] perhapsAsPat :: SDoc perhapsAsPat = text "Perhaps you meant an as-pattern, which must not be surrounded by whitespace" |