diff options
Diffstat (limited to 'compiler/GHC/Types/Name/Reader.hs')
| -rw-r--r-- | compiler/GHC/Types/Name/Reader.hs | 82 |
1 files changed, 1 insertions, 81 deletions
diff --git a/compiler/GHC/Types/Name/Reader.hs b/compiler/GHC/Types/Name/Reader.hs index 864101e8a9..05ea5a696b 100644 --- a/compiler/GHC/Types/Name/Reader.hs +++ b/compiler/GHC/Types/Name/Reader.hs @@ -71,11 +71,8 @@ module GHC.Types.Name.Reader ( ImportSpec(..), ImpDeclSpec(..), ImpItemSpec(..), importSpecLoc, importSpecModule, isExplicitItem, bestImport, - -- * Utils for StarIsType - starInfo, - -- * Utils - opIsAt, + opIsAt ) where import GHC.Prelude @@ -1374,83 +1371,6 @@ pprLoc :: SrcSpan -> SDoc pprLoc (RealSrcSpan s _) = text "at" <+> ppr s pprLoc (UnhelpfulSpan {}) = empty --- | Display info about the treatment of '*' under NoStarIsType. --- --- With StarIsType, three properties of '*' hold: --- --- (a) it is not an infix operator --- (b) it is always in scope --- (c) it is a synonym for Data.Kind.Type --- --- However, the user might not know that they are working on a module with --- NoStarIsType and write code that still assumes (a), (b), and (c), which --- actually do not hold in that module. --- --- Violation of (a) shows up in the parser. For instance, in the following --- examples, we have '*' not applied to enough arguments: --- --- data A :: * --- data F :: * -> * --- --- Violation of (b) or (c) show up in the renamer and the typechecker --- respectively. For instance: --- --- type K = Either * Bool --- --- This will parse differently depending on whether StarIsType is enabled, --- but it will parse nonetheless. With NoStarIsType it is parsed as a type --- operator, thus we have ((*) Either Bool). Now there are two cases to --- consider: --- --- 1. There is no definition of (*) in scope. In this case the renamer will --- fail to look it up. This is a violation of assumption (b). --- --- 2. There is a definition of the (*) type operator in scope (for example --- coming from GHC.TypeNats). In this case the user will get a kind --- mismatch error. This is a violation of assumption (c). --- --- The user might unknowingly be working on a module with NoStarIsType --- or use '*' as 'Data.Kind.Type' out of habit. So it is important to give a --- hint whenever an assumption about '*' is violated. Unfortunately, it is --- somewhat difficult to deal with (c), so we limit ourselves to (a) and (b). --- --- 'starInfo' generates an appropriate hint to the user depending on the --- extensions enabled in the module and the name that triggered the error. --- That is, if we have NoStarIsType and the error is related to '*' or its --- Unicode variant, the resulting SDoc will contain a helpful suggestion. --- Otherwise it is empty. --- -starInfo :: Bool -> RdrName -> SDoc -starInfo star_is_type rdr_name = - -- One might ask: if can use `sdocOption sdocStarIsType` here, why bother to - -- take star_is_type as input? Why not refactor? - -- - -- The reason is that `sdocOption sdocStarIsType` would indicate that - -- StarIsType is enabled in the module that tries to load the problematic - -- definition, not in the module that is being loaded. - -- - -- So if we have 'data T :: *' in a module with NoStarIsType, then the hint - -- must be displayed even if we load this definition from a module (or GHCi) - -- with StarIsType enabled! - -- - if isUnqualStar && not star_is_type - then text "With NoStarIsType, " <> - quotes (ppr rdr_name) <> - text " is treated as a regular type operator. " - $$ - text "Did you mean to use " <> quotes (text "Type") <> - text " from Data.Kind instead?" - else empty - where - -- Does rdr_name look like the user might have meant the '*' kind by it? - -- We focus on unqualified stars specifically, because qualified stars are - -- treated as type operators even under StarIsType. - isUnqualStar - | Unqual occName <- rdr_name - = let fs = occNameFS occName - in fs == fsLit "*" || fs == fsLit "★" - | otherwise = False - -- | Indicate if the given name is the "@" operator opIsAt :: RdrName -> Bool opIsAt e = e == mkUnqual varName (fsLit "@") |