diff options
author | Alec Theriault <alec.theriault@gmail.com> | 2020-04-21 10:53:28 -0400 |
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committer | Alec Theriault <alec.theriault@gmail.com> | 2020-04-21 08:06:45 -0700 |
commit | 5bc5016a14bc872a8315cddc629f8171a9ccd62e (patch) | |
tree | ff26691fdd58d13240668cad0e4175ea5de5c4d2 /haddock-api | |
parent | 83f0fa0b6218c34898337bf41072ee5fedec1bde (diff) |
Fallback to `hiDecl` when `extractDecl` fails
Sometimes, the declaration being exported is a subdecl (for instance, a
record accessor getting exported at the top-level). For these cases,
Haddock has to find a way to produce some synthetic sensible top-level
declaration. This is done with `extractDecl`.
As is shown by #1067, this is sometimes impossible to do just at a
syntactic level (for instance when the subdecl is re-exported). In these
cases, the only sensible thing to do is to try to reify a declaration
based on a GHC `TyThing` via `hiDecl`.
Diffstat (limited to 'haddock-api')
-rw-r--r-- | haddock-api/src/Haddock/Interface/Create.hs | 114 |
1 files changed, 69 insertions, 45 deletions
diff --git a/haddock-api/src/Haddock/Interface/Create.hs b/haddock-api/src/Haddock/Interface/Create.hs index 0f24afaa..5a58e1ac 100644 --- a/haddock-api/src/Haddock/Interface/Create.hs +++ b/haddock-api/src/Haddock/Interface/Create.hs @@ -793,11 +793,24 @@ availExportItem is_sig modMap thisMod semMod warnings exportedNames _ -> return [] + -- Tries 'extractDecl' first then falls back to 'hiDecl' if that fails + availDecl :: Name -> LHsDecl GhcRn -> ErrMsgGhc (LHsDecl GhcRn) + availDecl declName parentDecl = + case extractDecl declMap declName parentDecl of + Right d -> pure d + Left err -> do + synifiedDeclOpt <- hiDecl dflags declName + case synifiedDeclOpt of + Just synifiedDecl -> pure synifiedDecl + Nothing -> O.pprPanic "availExportItem" (O.text err) + availExportDecl :: AvailInfo -> LHsDecl GhcRn -> (DocForDecl Name, [(Name, DocForDecl Name)]) -> ErrMsgGhc [ ExportItem GhcRn ] availExportDecl avail decl (doc, subs) | availExportsDecl avail = do + extractedDecl <- availDecl (availName avail) decl + -- bundled pattern synonyms only make sense if the declaration is -- exported (otherwise there would be nothing to bundle to) bundledPatSyns <- findBundledPatterns avail @@ -813,8 +826,7 @@ availExportItem is_sig modMap thisMod semMod warnings exportedNames ] return [ ExportDecl { - expItemDecl = restrictTo (fmap fst subs) - (extractDecl declMap (availName avail) decl) + expItemDecl = restrictTo (fmap fst subs) extractedDecl , expItemPats = bundledPatSyns , expItemMbDoc = doc , expItemSubDocs = subs @@ -824,18 +836,18 @@ availExportItem is_sig modMap thisMod semMod warnings exportedNames } ] - | otherwise = - return [ ExportDecl { - expItemDecl = extractDecl declMap sub decl + | otherwise = for subs $ \(sub, sub_doc) -> do + extractedDecl <- availDecl sub decl + + return ( ExportDecl { + expItemDecl = extractedDecl , expItemPats = [] , expItemMbDoc = sub_doc , expItemSubDocs = [] , expItemInstances = [] , expItemFixities = [ (sub, f) | Just f <- [M.lookup sub fixMap] ] , expItemSpliced = False - } - | (sub, sub_doc) <- subs - ] + } ) exportedNameSet = mkNameSet exportedNames isExported n = elemNameSet n exportedNameSet @@ -910,6 +922,7 @@ semToIdMod this_uid m | Module.isHoleModule m = mkModule this_uid (moduleName m) | otherwise = m +-- | Reify a declaration from the GHC internal 'TyThing' representation. hiDecl :: DynFlags -> Name -> ErrMsgGhc (Maybe (LHsDecl GhcRn)) hiDecl dflags t = do mayTyThing <- liftGhcToErrMsgGhc $ lookupName t @@ -1053,20 +1066,30 @@ fullModuleContents is_sig modMap pkgName thisMod semMod warnings gre exportedNam isSigD (L _ SigD{}) = True isSigD _ = False + -- | Sometimes the declaration we want to export is not the "main" declaration: -- it might be an individual record selector or a class method. In these -- cases we have to extract the required declaration (and somehow cobble -- together a type signature for it...). -extractDecl :: DeclMap -> Name -> LHsDecl GhcRn -> LHsDecl GhcRn +-- +-- This function looks through the declarations in this module to try to find +-- the one with the right name. +extractDecl + :: DeclMap -- ^ all declarations in the file + -> Name -- ^ name of the declaration to extract + -> LHsDecl GhcRn -- ^ parent declaration + -> Either ErrMsg (LHsDecl GhcRn) extractDecl declMap name decl - | name `elem` getMainDeclBinder (unLoc decl) = decl + | name `elem` getMainDeclBinder (unLoc decl) = pure decl | otherwise = case unLoc decl of - TyClD _ d@ClassDecl {} -> + TyClD _ d@ClassDecl { tcdLName = L _ clsNm + , tcdSigs = clsSigs + , tcdATs = clsATs } -> let matchesMethod = [ lsig - | lsig <- tcdSigs d + | lsig <- clsSigs , ClassOpSig _ False _ _ <- pure $ unLoc lsig -- Note: exclude `default` declarations (see #505) , name `elem` sigName lsig @@ -1074,51 +1097,54 @@ extractDecl declMap name decl matchesAssociatedType = [ lfam_decl - | lfam_decl <- tcdATs d + | lfam_decl <- clsATs , name == unLoc (fdLName (unLoc lfam_decl)) ] -- TODO: document fixity in case (matchesMethod, matchesAssociatedType) of - ([s0], _) -> let (n, tyvar_names) = (tcdName d, tyClDeclTyVars d) - L pos sig = addClassContext n tyvar_names s0 - in L pos (SigD noExtField sig) - (_, [L pos fam_decl]) -> L pos (TyClD noExtField (FamDecl noExtField fam_decl)) + ([s0], _) -> let tyvar_names = tyClDeclTyVars d + L pos sig = addClassContext clsNm tyvar_names s0 + in pure (L pos (SigD noExtField sig)) + (_, [L pos fam_decl]) -> pure (L pos (TyClD noExtField (FamDecl noExtField fam_decl))) ([], []) | Just (famInstDecl:_) <- M.lookup name declMap -> extractDecl declMap name famInstDecl - _ -> O.pprPanic "extractDecl" (O.text "Ambiguous decl for" O.<+> O.ppr name O.<+> O.text "in class:" - O.$$ O.nest 4 (O.ppr d) - O.$$ O.text "Matches:" - O.$$ O.nest 4 (O.ppr matchesMethod O.<+> O.ppr matchesAssociatedType)) - TyClD _ d@DataDecl {} -> - let (n, tyvar_tys) = (tcdName d, lHsQTyVarsToTypes (tyClDeclTyVars d)) - in if isDataConName name - then SigD noExtField <$> extractPatternSyn name n (map HsValArg tyvar_tys) (dd_cons (tcdDataDefn d)) - else SigD noExtField <$> extractRecSel name n (map HsValArg tyvar_tys) (dd_cons (tcdDataDefn d)) + _ -> Left (concat [ "Ambiguous decl for ", getOccString name + , " in class ", getOccString clsNm ]) + + TyClD _ d@DataDecl { tcdLName = L _ dataNm + , tcdDataDefn = HsDataDefn { dd_cons = dataCons } } -> do + let ty_args = map HsValArg (lHsQTyVarsToTypes (tyClDeclTyVars d)) + lsig <- if isDataConName name + then extractPatternSyn name dataNm ty_args dataCons + else extractRecSel name dataNm ty_args dataCons + pure (SigD noExtField <$> lsig) + TyClD _ FamDecl {} | isValName name , Just (famInst:_) <- M.lookup name declMap -> extractDecl declMap name famInst InstD _ (DataFamInstD _ (DataFamInstDecl (HsIB { hsib_body = - FamEqn { feqn_tycon = L _ n - , feqn_pats = tys - , feqn_rhs = defn }}))) -> - if isDataConName name - then SigD noExtField <$> extractPatternSyn name n tys (dd_cons defn) - else SigD noExtField <$> extractRecSel name n tys (dd_cons defn) + FamEqn { feqn_tycon = L _ famName + , feqn_pats = ty_args + , feqn_rhs = HsDataDefn { dd_cons = dataCons } }}))) -> do + lsig <- if isDataConName name + then extractPatternSyn name famName ty_args dataCons + else extractRecSel name famName ty_args dataCons + pure (SigD noExtField <$> lsig) InstD _ (ClsInstD _ ClsInstDecl { cid_datafam_insts = insts }) | isDataConName name -> let matches = [ d' | L _ d'@(DataFamInstDecl (HsIB { hsib_body = - FamEqn { feqn_rhs = dd + FamEqn { feqn_rhs = HsDataDefn { dd_cons = dataCons } } })) <- insts - , name `elem` map unLoc (concatMap (getConNames . unLoc) (dd_cons dd)) + , name `elem` map unLoc (concatMap (getConNames . unLoc) dataCons) ] in case matches of [d0] -> extractDecl declMap name (noLoc (InstD noExtField (DataFamInstD noExtField d0))) - _ -> error "internal: extractDecl (ClsInstD)" + _ -> Left "internal: extractDecl (ClsInstD)" | otherwise -> let matches = [ d' | L _ d'@(DataFamInstDecl (HsIB { hsib_body = d })) <- insts @@ -1130,16 +1156,14 @@ extractDecl declMap name decl ] in case matches of [d0] -> extractDecl declMap name (noLoc . InstD noExtField $ DataFamInstD noExtField d0) - _ -> error "internal: extractDecl (ClsInstD)" - _ -> O.pprPanic "extractDecl" $ - O.text "Unhandled decl for" O.<+> O.ppr name O.<> O.text ":" - O.$$ O.nest 4 (O.ppr decl) + _ -> Left "internal: extractDecl (ClsInstD)" + _ -> Left ("extractDecl: Unhandled decl for " ++ getOccString name) -extractPatternSyn :: Name -> Name -> [LHsTypeArg GhcRn] -> [LConDecl GhcRn] -> LSig GhcRn +extractPatternSyn :: Name -> Name -> [LHsTypeArg GhcRn] -> [LConDecl GhcRn] -> Either ErrMsg (LSig GhcRn) extractPatternSyn nm t tvs cons = case filter matches cons of - [] -> error "extractPatternSyn: constructor pattern not found" - con:_ -> extract <$> con + [] -> Left "extractPatternSyn: constructor pattern not found" + con:_ -> pure (extract <$> con) where matches :: LConDecl GhcRn -> Bool matches (L _ con) = nm `elem` (unLoc <$> getConNames con) @@ -1170,13 +1194,13 @@ extractPatternSyn nm t tvs cons = mkAppTyArg f (HsArgPar _) = HsParTy noExtField f extractRecSel :: Name -> Name -> [LHsTypeArg GhcRn] -> [LConDecl GhcRn] - -> LSig GhcRn -extractRecSel _ _ _ [] = error "extractRecSel: selector not found" + -> Either ErrMsg (LSig GhcRn) +extractRecSel _ _ _ [] = Left "extractRecSel: selector not found" extractRecSel nm t tvs (L _ con : rest) = case getConArgs con of RecCon (L _ fields) | ((l,L _ (ConDeclField _ _nn ty _)) : _) <- matching_fields fields -> - L l (TypeSig noExtField [noLoc nm] (mkEmptySigWcType (noLoc (HsFunTy noExtField data_ty (getBangType ty))))) + pure (L l (TypeSig noExtField [noLoc nm] (mkEmptySigWcType (noLoc (HsFunTy noExtField data_ty (getBangType ty)))))) _ -> extractRecSel nm t tvs rest where matching_fields :: [LConDeclField GhcRn] -> [(SrcSpan, LConDeclField GhcRn)] |