import HscTypes ( HscEnv, hsc_dflags )
import BasicTypes ( Boxity(..) )
import ListSetOps ( findDupsEq )
-
+import Digraph ( SCC, flattenSCC, stronglyConnCompFromEdgedVertices )
import Control.Monad
+import Maybes( orElse )
import Data.Maybe
\end{code}
-- means we'll only report a declaration as unused if it isn't
-- mentioned at all. Ah well.
traceRn (text "Start rnTyClDecls") ;
- (rn_tycl_decls, src_fvs1) <- rnList rnTyClDecl tycl_decls ;
+ (rn_tycl_decls, src_fvs1) <- rnTyClDecls tycl_decls ;
-- (F) Rename Value declarations right-hand sides
traceRn (text "Start rnmono") ;
- (rn_val_decls, bind_dus) <- rnTopBindsRHS val_bndr_set new_lhs ;
+ (rn_val_decls, bind_dus) <- rnTopBindsRHS new_lhs ;
traceRn (text "finish rnmono" <+> ppr rn_val_decls) ;
-- (G) Rename Fixity and deprecations
inNewEnv env cont = do e <- env
setGblEnv e $ cont e
-rnTyClDecls :: [LTyClDecl RdrName] -> RnM [LTyClDecl Name]
--- Used for external core
-rnTyClDecls tycl_decls = do (decls', _fvs) <- rnList rnTyClDecl tycl_decls
- return decls'
-
addTcgDUs :: TcGblEnv -> DefUses -> TcGblEnv
-- This function could be defined lower down in the module hierarchy,
-- but there doesn't seem anywhere very logical to put it.
rnSrcWarnDecls bound_names decls
= do { -- check for duplicates
- ; mapM_ (\ (L loc rdr:lrdr':_) -> addErrAt loc (dupWarnDecl lrdr' rdr))
+ ; mapM_ (\ dups -> let (L loc rdr:lrdr':_) = dups
+ in addErrAt loc (dupWarnDecl lrdr' rdr))
warn_rdr_dups
; pairs_s <- mapM (addLocM rn_deprec) decls
; return (WarnSome ((concat pairs_s))) }
However, we can also do some scoping checks at the same time.
\begin{code}
+rnTyClDecls :: [[LTyClDecl RdrName]] -> RnM ([[LTyClDecl Name]], FreeVars)
+-- Renamed the declarations and do depedency analysis on them
+rnTyClDecls tycl_ds
+ = do { ds_w_fvs <- mapM (wrapLocFstM rnTyClDecl) (concat tycl_ds)
+
+ ; let sccs :: [SCC (LTyClDecl Name)]
+ sccs = depAnalTyClDecls ds_w_fvs
+
+ all_fvs = foldr (plusFV . snd) emptyFVs ds_w_fvs
+
+ ; return (map flattenSCC sccs, all_fvs) }
+
rnTyClDecl :: TyClDecl RdrName -> RnM (TyClDecl Name, FreeVars)
rnTyClDecl (ForeignType {tcdLName = name, tcdExtName = ext_name})
= lookupLocatedTopBndrRn name `thenM` \ name' ->
are no data constructors we allow h98_style = True
+\begin{code}
+depAnalTyClDecls :: [(LTyClDecl Name, FreeVars)] -> [SCC (LTyClDecl Name)]
+-- See Note [Dependency analysis of type and class decls]
+depAnalTyClDecls ds_w_fvs
+ = stronglyConnCompFromEdgedVertices edges
+ where
+ edges = [ (d, tcdName (unLoc d), map get_assoc (nameSetToList fvs))
+ | (d, fvs) <- ds_w_fvs ]
+ get_assoc n = lookupNameEnv assoc_env n `orElse` n
+ assoc_env = mkNameEnv [ (tcdName assoc_decl, cls_name)
+ | (L _ (ClassDecl { tcdLName = L _ cls_name
+ , tcdATs = ats }) ,_) <- ds_w_fvs
+ , L _ assoc_decl <- ats ]
+\end{code}
+
+Note [Dependency analysis of type and class decls]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+We need to do dependency analysis on type and class declarations
+else we get bad error messages. Consider
+
+ data T f a = MkT f a
+ data S f a = MkS f (T f a)
+
+This has a kind error, but the error message is better if you
+check T first, (fixing its kind) and *then* S. If you do kind
+inference together, you might get an error reported in S, which
+is jolly confusing. See Trac #4875
+
+
%*********************************************************
%* *
\subsection{Support code for type/data declarations}
Get the mapping from constructors to fields for this module.
It's convenient to do this after the data type decls have been renamed
\begin{code}
-extendRecordFieldEnv :: [LTyClDecl RdrName] -> [LInstDecl RdrName] -> TcM TcGblEnv
+extendRecordFieldEnv :: [[LTyClDecl RdrName]] -> [LInstDecl RdrName] -> TcM TcGblEnv
extendRecordFieldEnv tycl_decls inst_decls
= do { tcg_env <- getGblEnv
; field_env' <- foldrM get_con (tcg_field_env tcg_env) all_data_cons
all_data_cons :: [ConDecl RdrName]
all_data_cons = [con | L _ (TyData { tcdCons = cons }) <- all_tycl_decls
, L _ con <- cons ]
- all_tycl_decls = at_tycl_decls ++ tycl_decls
+ all_tycl_decls = at_tycl_decls ++ concat tycl_decls
at_tycl_decls = instDeclATs inst_decls -- Do not forget associated types!
get_con (ConDecl { con_name = con, con_details = RecCon flds })
add gp@(HsGroup {hs_tyclds = ts, hs_fixds = fs}) l (TyClD d) ds
| isClassDecl d
= let fsigs = [ L l f | L l (FixSig f) <- tcdSigs d ] in
- addl (gp { hs_tyclds = L l d : ts, hs_fixds = fsigs ++ fs}) ds
+ addl (gp { hs_tyclds = add_tycld (L l d) ts, hs_fixds = fsigs ++ fs}) ds
| otherwise
- = addl (gp { hs_tyclds = L l d : ts }) ds
+ = addl (gp { hs_tyclds = add_tycld (L l d) ts }) ds
-- Signatures: fixity sigs go a different place than all others
add gp@(HsGroup {hs_fixds = ts}) l (SigD (FixSig f)) ds
add gp l (DocD d) ds
= addl (gp { hs_docs = (L l d) : (hs_docs gp) }) ds
+add_tycld :: LTyClDecl a -> [[LTyClDecl a]] -> [[LTyClDecl a]]
+add_tycld d [] = [[d]]
+add_tycld d (ds:dss) = (d:ds) : dss
+
add_bind :: LHsBind a -> HsValBinds a -> HsValBinds a
add_bind b (ValBindsIn bs sigs) = ValBindsIn (bs `snocBag` b) sigs
add_bind _ (ValBindsOut {}) = panic "RdrHsSyn:add_bind"
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