%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[RnBinds]{Renaming and dependency analysis of bindings}
they may be affected by renaming (which isn't fully worked out yet).
\begin{code}
-#include "HsVersions.h"
-
module RnBinds (
- rnTopBinds,
- rnMethodBinds,
- rnBinds,
- SYN_IE(FreeVars),
- SYN_IE(DefinedVars)
+ rnTopBinds,
+ rnLocalBindsAndThen, rnValBindsAndThen, rnValBinds, trimWith,
+ rnMethodBinds, renameSigs,
+ rnMatchGroup, rnGRHSs
) where
-IMP_Ubiq()
-IMPORT_DELOOPER(RnLoop) -- break the RnPass/RnExpr/RnBinds loops
+#include "HsVersions.h"
+
+import {-# SOURCE #-} RnExpr( rnLExpr, rnStmts )
import HsSyn
-import HsPragmas ( isNoGenPragmas, noGenPragmas )
import RdrHsSyn
import RnHsSyn
-import RnMonad
-import RnExpr ( rnMatch, rnGRHSsAndBinds, rnPat, checkPrecMatch )
-
-import CmdLineOpts ( opt_SigsRequired )
-import Digraph ( stronglyConnComp )
-import ErrUtils ( addErrLoc, addShortErrLocLine )
-import Name ( getLocalName, RdrName )
-import Maybes ( catMaybes )
-import PprStyle--ToDo:rm
-import Pretty
-import UniqSet ( emptyUniqSet, unitUniqSet, mkUniqSet,
- unionUniqSets, unionManyUniqSets,
- elementOfUniqSet, uniqSetToList, SYN_IE(UniqSet) )
-import Util ( thenCmp, isIn, removeDups, panic, panic#, assertPanic, pprTrace{-ToDo:rm-} )
+import TcRnMonad
+import RnTypes ( rnHsSigType, rnLHsType, rnHsTypeFVs,
+ rnLPat, rnPatsAndThen, patSigErr, checkPrecMatch )
+import RnEnv ( bindLocatedLocalsRn, lookupLocatedBndrRn,
+ lookupLocatedInstDeclBndr, newIPNameRn,
+ lookupLocatedSigOccRn, bindPatSigTyVars, bindPatSigTyVarsFV,
+ bindLocalFixities, bindSigTyVarsFV,
+ warnUnusedLocalBinds, mapFvRn, extendTyVarEnvFVRn,
+ )
+import DynFlags ( DynFlag(..) )
+import Name ( Name, nameOccName, nameSrcLoc )
+import NameEnv
+import NameSet
+import PrelNames ( isUnboundName )
+import RdrName ( RdrName, rdrNameOcc )
+import SrcLoc ( mkSrcSpan, Located(..), unLoc )
+import ListSetOps ( findDupsEq )
+import BasicTypes ( RecFlag(..) )
+import Digraph ( SCC(..), stronglyConnComp )
+import Bag
+import Outputable
+import Maybes ( orElse, isJust )
+import Util ( filterOut )
+import Monad ( foldM )
\end{code}
-- ToDo: Put the annotations into the monad, so that they arrive in the proper
ToDo: deal with case where a single monobinds binds the same variable
twice.
-Sets of variable names are represented as sets explicitly, rather than lists.
-
-\begin{code}
-type DefinedVars = UniqSet RnName
-type FreeVars = UniqSet RnName
-\end{code}
-
-i.e., binders.
-
The vertag tag is a unique @Int@; the tags only need to be unique
within one @MonoBinds@, so that unique-Int plumbing is done explicitly
(heavy monad machinery not needed).
-\begin{code}
-type VertexTag = Int
-type Cycle = [VertexTag]
-type Edge = (VertexTag, VertexTag)
-\end{code}
%************************************************************************
%* *
%* naming conventions *
%* *
%************************************************************************
+
\subsection[name-conventions]{Name conventions}
The basic algorithm involves walking over the tree and returning a tuple
%************************************************************************
%* *
-%* analysing polymorphic bindings (HsBinds, Bind, MonoBinds) *
+%* analysing polymorphic bindings (HsBindGroup, HsBind)
%* *
%************************************************************************
+
\subsubsection[dep-HsBinds]{Polymorphic bindings}
Non-recursive expressions are reconstructed without any changes at top
\Haskell{} programs, and this code should not be executed.
Monomorphic bindings contain information that is returned in a tuple
-(a @FlatMonoBindsInfo@) containing:
+(a @FlatMonoBinds@) containing:
\begin{enumerate}
\item
it expects the global environment to contain bindings for the binders
(which are all class operations).
-\begin{code}
-rnTopBinds :: RdrNameHsBinds -> RnM_Fixes s RenamedHsBinds
-rnMethodBinds :: RnName{-class-} -> RdrNameMonoBinds -> RnM_Fixes s RenamedMonoBinds
-rnBinds :: RdrNameHsBinds -> RnM_Fixes s (RenamedHsBinds, FreeVars, [RnName])
-
-rnTopBinds EmptyBinds = returnRn EmptyBinds
-rnTopBinds (SingleBind (RecBind bind)) = rnTopMonoBinds bind []
-rnTopBinds (BindWith (RecBind bind) sigs) = rnTopMonoBinds bind sigs
- -- the parser doesn't produce other forms
-
--- ********************************************************************
-
-rnMethodBinds class_name EmptyMonoBinds = returnRn EmptyMonoBinds
+%************************************************************************
+%* *
+\subsubsection{ Top-level bindings}
+%* *
+%************************************************************************
-rnMethodBinds class_name (AndMonoBinds mb1 mb2)
- = andRn AndMonoBinds (rnMethodBinds class_name mb1)
- (rnMethodBinds class_name mb2)
+@rnTopMonoBinds@ assumes that the environment already
+contains bindings for the binders of this particular binding.
-rnMethodBinds class_name (FunMonoBind occname inf matches locn)
- = pushSrcLocRn locn $
- lookupClassOp class_name occname `thenRn` \ op_name ->
- mapAndUnzipRn rnMatch matches `thenRn` \ (new_matches, _) ->
- mapRn (checkPrecMatch inf op_name) new_matches `thenRn_`
- returnRn (FunMonoBind op_name inf new_matches locn)
+\begin{code}
+rnTopBinds :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)
+
+-- The binders of the binding are in scope already;
+-- the top level scope resolution does that
+
+rnTopBinds binds
+ = do { is_boot <- tcIsHsBoot
+ ; if is_boot then rnTopBindsBoot binds
+ else rnTopBindsSrc binds }
+
+rnTopBindsBoot :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)
+-- A hs-boot file has no bindings.
+-- Return a single HsBindGroup with empty binds and renamed signatures
+rnTopBindsBoot (ValBindsIn mbinds sigs)
+ = do { checkErr (isEmptyLHsBinds mbinds) (bindsInHsBootFile mbinds)
+ ; sigs' <- renameSigs okHsBootSig sigs
+ ; return (ValBindsOut [] sigs', usesOnly (hsSigsFVs sigs')) }
+
+rnTopBindsSrc :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)
+rnTopBindsSrc binds@(ValBindsIn mbinds _)
+ = do { (binds', dus) <- rnValBinds noTrim binds
+
+ -- Warn about missing signatures,
+ ; let { ValBindsOut _ sigs' = binds'
+ ; ty_sig_vars = mkNameSet [ unLoc n | L _ (TypeSig n _) <- sigs']
+ ; un_sigd_bndrs = duDefs dus `minusNameSet` ty_sig_vars }
+
+ ; warn_missing_sigs <- doptM Opt_WarnMissingSigs
+ ; ifM (warn_missing_sigs)
+ (mappM_ missingSigWarn (nameSetToList un_sigd_bndrs))
+
+ ; return (binds', dus)
+ }
+\end{code}
-rnMethodBinds class_name (PatMonoBind (VarPatIn occname) grhss_and_binds locn)
- = pushSrcLocRn locn $
- lookupClassOp class_name occname `thenRn` \ op_name ->
- rnGRHSsAndBinds grhss_and_binds `thenRn` \ (grhss_and_binds', _) ->
- returnRn (PatMonoBind (VarPatIn op_name) grhss_and_binds' locn)
--- Can't handle method pattern-bindings which bind multiple methods.
-rnMethodBinds _ mbind@(PatMonoBind other_pat _ locn)
- = failButContinueRn EmptyMonoBinds (methodBindErr mbind locn)
--- ********************************************************************
+%*********************************************************
+%* *
+ HsLocalBinds
+%* *
+%*********************************************************
-rnBinds EmptyBinds = returnRn (EmptyBinds,emptyUniqSet,[])
-rnBinds (SingleBind (RecBind bind)) = rnNestedMonoBinds bind []
-rnBinds (BindWith (RecBind bind) sigs) = rnNestedMonoBinds bind sigs
- -- the parser doesn't produce other forms
+\begin{code}
+rnLocalBindsAndThen
+ :: HsLocalBinds RdrName
+ -> (HsLocalBinds Name -> RnM (result, FreeVars))
+ -> RnM (result, FreeVars)
+-- This version (a) assumes that the binding vars are not already in scope
+-- (b) removes the binders from the free vars of the thing inside
+-- The parser doesn't produce ThenBinds
+rnLocalBindsAndThen EmptyLocalBinds thing_inside
+ = thing_inside EmptyLocalBinds
+
+rnLocalBindsAndThen (HsValBinds val_binds) thing_inside
+ = rnValBindsAndThen val_binds $ \ val_binds' ->
+ thing_inside (HsValBinds val_binds')
+
+rnLocalBindsAndThen (HsIPBinds binds) thing_inside
+ = rnIPBinds binds `thenM` \ (binds',fv_binds) ->
+ thing_inside (HsIPBinds binds') `thenM` \ (thing, fvs_thing) ->
+ returnM (thing, fvs_thing `plusFV` fv_binds)
+
+-------------
+rnIPBinds (IPBinds ip_binds _no_dict_binds)
+ = do { (ip_binds', fvs_s) <- mapAndUnzipM (wrapLocFstM rnIPBind) ip_binds
+ ; return (IPBinds ip_binds' emptyLHsBinds, plusFVs fvs_s) }
+
+rnIPBind (IPBind n expr)
+ = newIPNameRn n `thenM` \ name ->
+ rnLExpr expr `thenM` \ (expr',fvExpr) ->
+ return (IPBind name expr', fvExpr)
\end{code}
-@rnNestedMonoBinds@
- - collects up the binders for this declaration group,
- - checkes that they form a set
- - extends the environment to bind them to new local names
- - calls @rnMonoBinds@ to do the real work
-In contrast, @rnTopMonoBinds@ doesn't extend the environment, because that's
-already done in pass3. All it does is call @rnMonoBinds@ and discards
-the free var info.
+%************************************************************************
+%* *
+ ValBinds
+%* *
+%************************************************************************
\begin{code}
-rnTopMonoBinds :: RdrNameMonoBinds -> [RdrNameSig] -> RnM_Fixes s RenamedHsBinds
+rnValBindsAndThen :: HsValBinds RdrName
+ -> (HsValBinds Name -> RnM (result, FreeVars))
+ -> RnM (result, FreeVars)
-rnTopMonoBinds EmptyMonoBinds sigs = returnRn EmptyBinds
-
-rnTopMonoBinds mbs sigs
- = rnBindSigs True{-top-level-} (collectMonoBinders mbs) sigs `thenRn` \ siglist ->
- rnMonoBinds mbs siglist `thenRn` \ (new_binds, fv_set) ->
- returnRn new_binds
+rnValBindsAndThen binds@(ValBindsIn mbinds sigs) thing_inside
+ = -- Extract all the binders in this group, and extend the
+ -- current scope, inventing new names for the new binders
+ -- This also checks that the names form a set
+ bindLocatedLocalsRn doc mbinders_w_srclocs $ \ bndrs ->
+ -- Then install local fixity declarations
+ -- Notice that they scope over thing_inside too
+ bindLocalFixities [sig | L _ (FixSig sig) <- sigs ] $
-rnNestedMonoBinds :: RdrNameMonoBinds -> [RdrNameSig]
- -> RnM_Fixes s (RenamedHsBinds, FreeVars, [RnName])
+ -- Do the business
+ rnValBinds (trimWith bndrs) binds `thenM` \ (binds, bind_dus) ->
-rnNestedMonoBinds EmptyMonoBinds sigs
- = returnRn (EmptyBinds, emptyUniqSet, [])
+ -- Now do the "thing inside"
+ thing_inside binds `thenM` \ (result,result_fvs) ->
-rnNestedMonoBinds mbinds sigs -- Non-empty monobinds
- =
- -- Extract all the binders in this group,
- -- and extend current scope, inventing new names for the new binders
- -- This also checks that the names form a set
+ -- Final error checking
let
- mbinders_w_srclocs = collectMonoBindersAndLocs mbinds
- mbinders = map fst mbinders_w_srclocs
+ all_uses = duUses bind_dus `plusFV` result_fvs
+ -- duUses: It's important to return all the uses, not the 'real uses'
+ -- used for warning about unused bindings. Otherwise consider:
+ -- x = 3
+ -- y = let p = x in 'x' -- NB: p not used
+ -- If we don't "see" the dependency of 'y' on 'x', we may put the
+ -- bindings in the wrong order, and the type checker will complain
+ -- that x isn't in scope
+
+ unused_bndrs = [ b | b <- bndrs, not (b `elemNameSet` all_uses)]
in
- newLocalNames "variable"
- mbinders_w_srclocs `thenRn` \ new_mbinders ->
-
- extendSS2 new_mbinders (
- rnBindSigs False{-not top- level-} mbinders sigs `thenRn` \ siglist ->
- rnMonoBinds mbinds siglist
- ) `thenRn` \ (new_binds, fv_set) ->
- returnRn (new_binds, fv_set, new_mbinders)
-\end{code}
+ warnUnusedLocalBinds unused_bndrs `thenM_`
-@rnMonoBinds@ is used by *both* top-level and nested bindings. It
-assumes that all variables bound in this group are already in scope.
-This is done *either* by pass 3 (for the top-level bindings),
-*or* by @rnNestedMonoBinds@ (for the nested ones).
+ returnM (result, delListFromNameSet all_uses bndrs)
+ where
+ mbinders_w_srclocs = collectHsBindLocatedBinders mbinds
+ doc = text "In the binding group for:"
+ <+> pprWithCommas ppr (map unLoc mbinders_w_srclocs)
-\begin{code}
-rnMonoBinds :: RdrNameMonoBinds
- -> [RenamedSig] -- Signatures attached to this group
- -> RnM_Fixes s (RenamedHsBinds, FreeVars)
+---------------------
+rnValBinds :: (FreeVars -> FreeVars)
+ -> HsValBinds RdrName
+ -> RnM (HsValBinds Name, DefUses)
+-- Assumes the binders of the binding are in scope already
-rnMonoBinds mbinds siglist
- =
- -- Rename the bindings, returning a MonoBindsInfo
- -- which is a list of indivisible vertices so far as
- -- the strongly-connected-components (SCC) analysis is concerned
- flattenMonoBinds 0 siglist mbinds `thenRn` \ (_, mbinds_info) ->
+rnValBinds trim (ValBindsIn mbinds sigs)
+ = do { sigs' <- rename_sigs sigs
- -- Do the SCC analysis
- let vertices = mkVertices mbinds_info
- edges = mkEdges mbinds_info
+ ; binds_w_dus <- mapBagM (rnBind (mkSigTvFn sigs') trim) mbinds
- scc_result = stronglyConnComp (==) edges vertices
+ ; let (binds', bind_dus) = depAnalBinds binds_w_dus
- -- Deal with bound and free-var calculation
- rhs_free_vars = foldr f emptyUniqSet mbinds_info
+ -- We do the check-sigs after renaming the bindings,
+ -- so that we have convenient access to the binders
+ ; check_sigs (okBindSig (duDefs bind_dus)) sigs'
- final_binds = reconstructRec scc_result edges mbinds_info
+ ; return (ValBindsOut binds' sigs',
+ usesOnly (hsSigsFVs sigs') `plusDU` bind_dus) }
- happy_answer = returnRn (final_binds, rhs_free_vars)
- in
- case (inline_sigs_in_recursive_binds final_binds) of
- Nothing -> happy_answer
- Just names_n_locns ->
--- SLPJ: sometimes want recursive INLINE for worker wrapper style stuff
--- addErrRn (inlineInRecursiveBindsErr names_n_locns) `thenRn_`
- {-not so-}happy_answer
+
+---------------------
+depAnalBinds :: Bag (LHsBind Name, [Name], Uses)
+ -> ([(RecFlag, LHsBinds Name)], DefUses)
+-- Dependency analysis; this is important so that
+-- unused-binding reporting is accurate
+depAnalBinds binds_w_dus
+ = (map get_binds sccs, map get_du sccs)
+ where
+ sccs = stronglyConnComp edges
+
+ keyd_nodes = bagToList binds_w_dus `zip` [0::Int ..]
+
+ edges = [ (node, key, [key | n <- nameSetToList uses,
+ Just key <- [lookupNameEnv key_map n] ])
+ | (node@(_,_,uses), key) <- keyd_nodes ]
+
+ key_map :: NameEnv Int -- Which binding it comes from
+ key_map = mkNameEnv [(bndr, key) | ((_, bndrs, _), key) <- keyd_nodes
+ , bndr <- bndrs ]
+
+ get_binds (AcyclicSCC (bind, _, _)) = (NonRecursive, unitBag bind)
+ get_binds (CyclicSCC binds_w_dus) = (Recursive, listToBag [b | (b,d,u) <- binds_w_dus])
+
+ get_du (AcyclicSCC (_, bndrs, uses)) = (Just (mkNameSet bndrs), uses)
+ get_du (CyclicSCC binds_w_dus) = (Just defs, uses)
+ where
+ defs = mkNameSet [b | (_,bs,_) <- binds_w_dus, b <- bs]
+ uses = unionManyNameSets [u | (_,_,u) <- binds_w_dus]
+
+
+---------------------
+-- Bind the top-level forall'd type variables in the sigs.
+-- E.g f :: a -> a
+-- f = rhs
+-- The 'a' scopes over the rhs
+--
+-- NB: there'll usually be just one (for a function binding)
+-- but if there are many, one may shadow the rest; too bad!
+-- e.g x :: [a] -> [a]
+-- y :: [(a,a)] -> a
+-- (x,y) = e
+-- In e, 'a' will be in scope, and it'll be the one from 'y'!
+
+mkSigTvFn :: [LSig Name] -> (Name -> [Name])
+-- Return a lookup function that maps an Id Name to the names
+-- of the type variables that should scope over its body..
+mkSigTvFn sigs
+ = \n -> lookupNameEnv env n `orElse` []
where
- f :: (a,b, FreeVars, c,d) -> FreeVars -> FreeVars
-
- f (_, _, fvs_body, _, _) fvs_sofar = fvs_sofar `unionUniqSets` fvs_body
-
- inline_sigs_in_recursive_binds (BindWith (RecBind _) sigs)
- = case [(n, locn) | (InlineSig n locn) <- sigs ] of
- [] -> Nothing
- sigh ->
-#if OMIT_DEFORESTER
- Just sigh
-#else
- -- Allow INLINEd recursive functions if they are
- -- designated DEFORESTable too.
- case [(n, locn) | (DeforestSig n locn) <- sigs ] of
- [] -> Just sigh
- sigh -> Nothing
-#endif
-
- inline_sigs_in_recursive_binds (ThenBinds b1 b2)
- = case (inline_sigs_in_recursive_binds b1) of
- Nothing -> inline_sigs_in_recursive_binds b2
- Just x -> Just x -- NB: won't report error(s) in b2
-
- inline_sigs_in_recursive_binds anything_else = Nothing
+ env :: NameEnv [Name]
+ env = mkNameEnv [ (name, map hsLTyVarName ltvs)
+ | L _ (TypeSig (L _ name)
+ (L _ (HsForAllTy Explicit ltvs _ _))) <- sigs]
+ -- Note the pattern-match on "Explicit"; we only bind
+ -- type variables from signatures with an explicit top-level for-all
+
+-- The trimming function trims the free vars we attach to a
+-- binding so that it stays reasonably small
+noTrim :: FreeVars -> FreeVars
+noTrim fvs = fvs -- Used at top level
+
+trimWith :: [Name] -> FreeVars -> FreeVars
+-- Nested bindings; trim by intersection with the names bound here
+trimWith bndrs = intersectNameSet (mkNameSet bndrs)
+
+---------------------
+rnBind :: (Name -> [Name]) -- Signature tyvar function
+ -> (FreeVars -> FreeVars) -- Trimming function for rhs free vars
+ -> LHsBind RdrName
+ -> RnM (LHsBind Name, [Name], Uses)
+rnBind sig_fn trim (L loc (PatBind { pat_lhs = pat, pat_rhs = grhss }))
+ = setSrcSpan loc $
+ do { (pat', pat_fvs) <- rnLPat pat
+
+ ; let bndrs = collectPatBinders pat'
+
+ ; (grhss', fvs) <- bindSigTyVarsFV (concatMap sig_fn bndrs) $
+ rnGRHSs PatBindRhs grhss
+
+ ; return (L loc (PatBind { pat_lhs = pat', pat_rhs = grhss',
+ pat_rhs_ty = placeHolderType, bind_fvs = trim fvs }),
+ bndrs, pat_fvs `plusFV` fvs) }
+
+rnBind sig_fn trim (L loc (FunBind { fun_id = name, fun_infix = inf, fun_matches = matches }))
+ = setSrcSpan loc $
+ do { new_name <- lookupLocatedBndrRn name
+ ; let plain_name = unLoc new_name
+
+ ; (matches', fvs) <- bindSigTyVarsFV (sig_fn plain_name) $
+ rnMatchGroup (FunRhs plain_name) matches
+
+ ; checkPrecMatch inf plain_name matches'
+
+ ; return (L loc (FunBind { fun_id = new_name, fun_infix = inf, fun_matches = matches',
+ bind_fvs = trim fvs, fun_co_fn = idCoercion }),
+ [plain_name], fvs)
+ }
\end{code}
-@flattenMonoBinds@ is ever-so-slightly magical in that it sticks
-unique ``vertex tags'' on its output; minor plumbing required.
-\begin{code}
-flattenMonoBinds :: Int -- Next free vertex tag
- -> [RenamedSig] -- Signatures
- -> RdrNameMonoBinds
- -> RnM_Fixes s (Int, FlatMonoBindsInfo)
-
-flattenMonoBinds uniq sigs EmptyMonoBinds = returnRn (uniq, [])
-
-flattenMonoBinds uniq sigs (AndMonoBinds bs1 bs2)
- = flattenMonoBinds uniq sigs bs1 `thenRn` \ (uniq1, flat1) ->
- flattenMonoBinds uniq1 sigs bs2 `thenRn` \ (uniq2, flat2) ->
- returnRn (uniq2, flat1 ++ flat2)
-
-flattenMonoBinds uniq sigs (PatMonoBind pat grhss_and_binds locn)
- = pushSrcLocRn locn $
- rnPat pat `thenRn` \ pat' ->
- rnGRHSsAndBinds grhss_and_binds `thenRn` \ (grhss_and_binds', fvs) ->
-
- -- Find which things are bound in this group
- let
- names_bound_here = collectPatBinders pat'
-
- sigs_etc_for_here = foldl (sig_for_here (\ n -> n `is_elem` names_bound_here))
- [] sigs
+@rnMethodBinds@ is used for the method bindings of a class and an instance
+declaration. Like @rnBinds@ but without dependency analysis.
- sigs_fvs = foldr sig_fv emptyUniqSet sigs_etc_for_here
+NOTA BENE: we record each {\em binder} of a method-bind group as a free variable.
+That's crucial when dealing with an instance decl:
+\begin{verbatim}
+ instance Foo (T a) where
+ op x = ...
+\end{verbatim}
+This might be the {\em sole} occurrence of @op@ for an imported class @Foo@,
+and unless @op@ occurs we won't treat the type signature of @op@ in the class
+decl for @Foo@ as a source of instance-decl gates. But we should! Indeed,
+in many ways the @op@ in an instance decl is just like an occurrence, not
+a binder.
- is_elem = isIn "flattenMonoBinds"
+\begin{code}
+rnMethodBinds :: Name -- Class name
+ -> [Name] -- Names for generic type variables
+ -> LHsBinds RdrName
+ -> RnM (LHsBinds Name, FreeVars)
+
+rnMethodBinds cls gen_tyvars binds
+ = foldM do_one (emptyBag,emptyFVs) (bagToList binds)
+ where do_one (binds,fvs) bind = do
+ (bind', fvs_bind) <- rnMethodBind cls gen_tyvars bind
+ return (bind' `unionBags` binds, fvs_bind `plusFV` fvs)
+
+rnMethodBind cls gen_tyvars (L loc (FunBind { fun_id = name, fun_infix = inf,
+ fun_matches = MatchGroup matches _ }))
+ = setSrcSpan loc $
+ lookupLocatedInstDeclBndr cls name `thenM` \ sel_name ->
+ let plain_name = unLoc sel_name in
+ -- We use the selector name as the binder
+
+ mapFvRn (rn_match plain_name) matches `thenM` \ (new_matches, fvs) ->
+ let
+ new_group = MatchGroup new_matches placeHolderType
in
- returnRn (
- uniq + 1,
- [(uniq,
- mkUniqSet names_bound_here,
- fvs `unionUniqSets` sigs_fvs,
- PatMonoBind pat' grhss_and_binds' locn,
- sigs_etc_for_here
- )]
- )
-
-flattenMonoBinds uniq sigs (FunMonoBind name inf matches locn)
- = pushSrcLocRn locn $
- lookupValue name `thenRn` \ name' ->
- mapAndUnzipRn rnMatch matches `thenRn` \ (new_matches, fv_lists) ->
- mapRn (checkPrecMatch inf name') new_matches `thenRn_`
- let
- fvs = unionManyUniqSets fv_lists
+ checkPrecMatch inf plain_name new_group `thenM_`
+ returnM (unitBag (L loc (FunBind { fun_id = sel_name, fun_infix = inf, fun_matches = new_group,
+ bind_fvs = fvs, fun_co_fn = idCoercion })),
+ fvs `addOneFV` plain_name)
+ -- The 'fvs' field isn't used for method binds
+ where
+ -- Truly gruesome; bring into scope the correct members of the generic
+ -- type variables. See comments in RnSource.rnSourceDecl(ClassDecl)
+ rn_match sel_name match@(L _ (Match (L _ (TypePat ty) : _) _ _))
+ = extendTyVarEnvFVRn gen_tvs $
+ rnMatch (FunRhs sel_name) match
+ where
+ tvs = map (rdrNameOcc.unLoc) (extractHsTyRdrTyVars ty)
+ gen_tvs = [tv | tv <- gen_tyvars, nameOccName tv `elem` tvs]
- sigs_for_me = foldl (sig_for_here (\ n -> n == name')) [] sigs
+ rn_match sel_name match = rnMatch (FunRhs sel_name) match
- sigs_fvs = foldr sig_fv emptyUniqSet sigs_for_me
- in
- returnRn (
- uniq + 1,
- [(uniq,
- unitUniqSet name',
- fvs `unionUniqSets` sigs_fvs,
- FunMonoBind name' inf new_matches locn,
- sigs_for_me
- )]
- )
-\end{code}
-Grab type-signatures/user-pragmas of interest:
-\begin{code}
-sig_for_here want_me acc s@(Sig n _ _ _) | want_me n = s:acc
-sig_for_here want_me acc s@(InlineSig n _) | want_me n = s:acc
-sig_for_here want_me acc s@(DeforestSig n _) | want_me n = s:acc
-sig_for_here want_me acc s@(SpecSig n _ _ _) | want_me n = s:acc
-sig_for_here want_me acc s@(MagicUnfoldingSig n _ _)
- | want_me n = s:acc
-sig_for_here want_me acc other_wise = acc
-
--- If a SPECIALIZE pragma is of the "... = blah" form,
--- then we'd better make sure "blah" is taken into
--- acct in the dependency analysis (or we get an
--- unexpected out-of-scope error)! WDP 95/07
-
-sig_fv (SpecSig _ _ (Just blah) _) acc = acc `unionUniqSets` unitUniqSet blah
-sig_fv _ acc = acc
+-- Can't handle method pattern-bindings which bind multiple methods.
+rnMethodBind cls gen_tyvars mbind@(L loc (PatBind other_pat _ _ _))
+ = addLocErr mbind methodBindErr `thenM_`
+ returnM (emptyBag, emptyFVs)
\end{code}
+
%************************************************************************
%* *
-\subsection[reconstruct-deps]{Reconstructing dependencies}
+\subsubsection[dep-Sigs]{Signatures (and user-pragmas for values)}
%* *
%************************************************************************
-This @MonoBinds@- and @ClassDecls@-specific code is segregated here,
-as the two cases are similar.
+@renameSigs@ checks for:
+\begin{enumerate}
+\item more than one sig for one thing;
+\item signatures given for things not bound here;
+\item with suitably flaggery, that all top-level things have type signatures.
+\end{enumerate}
+%
+At the moment we don't gather free-var info from the types in
+signatures. We'd only need this if we wanted to report unused tyvars.
\begin{code}
-reconstructRec :: [Cycle] -- Result of SCC analysis; at least one
- -> [Edge] -- Original edges
- -> FlatMonoBindsInfo
- -> RenamedHsBinds
-
-reconstructRec cycles edges mbi
- = foldr1 ThenBinds (map (reconstructCycle mbi) cycles)
+renameSigs :: (LSig Name -> Bool) -> [LSig RdrName] -> RnM [LSig Name]
+-- Renames the signatures and performs error checks
+renameSigs ok_sig sigs
+ = do { sigs' <- rename_sigs sigs
+ ; check_sigs ok_sig sigs'
+ ; return sigs' }
+
+----------------------
+rename_sigs :: [LSig RdrName] -> RnM [LSig Name]
+rename_sigs sigs = mappM (wrapLocM renameSig)
+ (filter (not . isFixityLSig) sigs)
+ -- Remove fixity sigs which have been dealt with already
+
+----------------------
+check_sigs :: (LSig Name -> Bool) -> [LSig Name] -> RnM ()
+-- Used for class and instance decls, as well as regular bindings
+check_sigs ok_sig sigs
+ -- Check for (a) duplicate signatures
+ -- (b) signatures for things not in this group
+ = do { mappM_ unknownSigErr (filter (not . ok_sig) sigs')
+ ; mappM_ dupSigDeclErr (findDupsEq eqHsSig sigs') }
where
- reconstructCycle :: FlatMonoBindsInfo -> Cycle -> RenamedHsBinds
-
- reconstructCycle mbi2 cycle
- = case [(binds,sigs) | (vertex, _, _, binds, sigs) <- mbi2, vertex `is_elem` cycle]
- of { relevant_binds_and_sigs ->
-
- case (unzip relevant_binds_and_sigs) of { (binds, sig_lists) ->
-
- case (foldr AndMonoBinds EmptyMonoBinds binds) of { this_gp_binds ->
- let
- this_gp_sigs = foldr1 (++) sig_lists
- have_sigs = not (null sig_lists)
- -- ToDo: this might not be the right
- -- thing to call this predicate;
- -- e.g. "have_sigs [[], [], []]" ???????????
- in
- mk_binds this_gp_binds this_gp_sigs (isCyclic edges cycle) have_sigs
- }}}
- where
- is_elem = isIn "reconstructRec"
-
- mk_binds :: RenamedMonoBinds -> [RenamedSig]
- -> Bool -> Bool -> RenamedHsBinds
-
- mk_binds bs ss True False = SingleBind (RecBind bs)
- mk_binds bs ss True True{-have sigs-} = BindWith (RecBind bs) ss
- mk_binds bs ss False False = SingleBind (NonRecBind bs)
- mk_binds bs ss False True{-have sigs-} = BindWith (NonRecBind bs) ss
-
- -- moved from Digraph, as this is the only use here
- -- (avoid overloading cost). We have to use elem
- -- (not FiniteMaps or whatever), because there may be
- -- many edges out of one vertex. We give it its own
- -- "elem" just for speed.
-
- isCyclic es [] = panic "isCyclic: empty component"
- isCyclic es [v] = (v,v) `elem` es
- isCyclic es vs = True
-
- elem _ [] = False
- elem x (y:ys) = x==y || elem x ys
+ -- Don't complain about an unbound name again
+ sigs' = filterOut bad_name sigs
+ bad_name sig = case sigName sig of
+ Just n -> isUnboundName n
+ other -> False
+
+-- We use lookupLocatedSigOccRn in the signatures, which is a little bit unsatisfactory
+-- because this won't work for:
+-- instance Foo T where
+-- {-# INLINE op #-}
+-- Baz.op = ...
+-- We'll just rename the INLINE prag to refer to whatever other 'op'
+-- is in scope. (I'm assuming that Baz.op isn't in scope unqualified.)
+-- Doesn't seem worth much trouble to sort this.
+
+renameSig :: Sig RdrName -> RnM (Sig Name)
+-- FixitSig is renamed elsewhere.
+renameSig (TypeSig v ty)
+ = lookupLocatedSigOccRn v `thenM` \ new_v ->
+ rnHsSigType (quotes (ppr v)) ty `thenM` \ new_ty ->
+ returnM (TypeSig new_v new_ty)
+
+renameSig (SpecInstSig ty)
+ = rnLHsType (text "A SPECIALISE instance pragma") ty `thenM` \ new_ty ->
+ returnM (SpecInstSig new_ty)
+
+renameSig (SpecSig v ty inl)
+ = lookupLocatedSigOccRn v `thenM` \ new_v ->
+ rnHsSigType (quotes (ppr v)) ty `thenM` \ new_ty ->
+ returnM (SpecSig new_v new_ty inl)
+
+renameSig (InlineSig v s)
+ = lookupLocatedSigOccRn v `thenM` \ new_v ->
+ returnM (InlineSig new_v s)
\end{code}
-%************************************************************************
-%* *
-%* Manipulating FlatMonoBindInfo *
-%* *
-%************************************************************************
-During analysis a @MonoBinds@ is flattened to a @FlatMonoBindsInfo@.
-The @RenamedMonoBinds@ is always an empty bind, a pattern binding or
-a function binding, and has itself been dependency-analysed and
-renamed.
+************************************************************************
+* *
+\subsection{Match}
+* *
+************************************************************************
\begin{code}
-type FlatMonoBindsInfo
- = [(VertexTag, -- Identifies the vertex
- UniqSet RnName, -- Set of names defined in this vertex
- UniqSet RnName, -- Set of names used in this vertex
- RenamedMonoBinds, -- Binding for this vertex (always just one binding, either fun or pat)
- [RenamedSig]) -- Signatures, if any, for this vertex
- ]
-
-mkVertices :: FlatMonoBindsInfo -> [VertexTag]
-mkEdges :: FlatMonoBindsInfo -> [Edge]
-
-mkVertices info = [ vertex | (vertex,_,_,_,_) <- info]
-
-mkEdges flat_info
- -- An edge (v,v') indicates that v depends on v'
- = -- pprTrace "mkEdges:" (ppAboves [ppAboves[ppInt v, ppCat [ppr PprDebug d|d <- uniqSetToList defd], ppCat [ppr PprDebug u|u <- uniqSetToList used]] | (v,defd,used,_,_) <- flat_info]) $
- [ (source_vertex, target_vertex)
- | (source_vertex, _, used_names, _, _) <- flat_info,
- target_name <- uniqSetToList used_names,
- target_vertex <- vertices_defining target_name flat_info
- ]
- where
- -- If each name only has one binding in this group, then
- -- vertices_defining will always return the empty list, or a
- -- singleton. The case when there is more than one binding (an
- -- error) needs more thought.
-
- vertices_defining name flat_info2
- = [ vertex | (vertex, names_defined, _, _, _) <- flat_info2,
- name `elementOfUniqSet` names_defined
- ]
+rnMatchGroup :: HsMatchContext Name -> MatchGroup RdrName -> RnM (MatchGroup Name, FreeVars)
+rnMatchGroup ctxt (MatchGroup ms _)
+ = mapFvRn (rnMatch ctxt) ms `thenM` \ (new_ms, ms_fvs) ->
+ returnM (MatchGroup new_ms placeHolderType, ms_fvs)
+
+rnMatch :: HsMatchContext Name -> LMatch RdrName -> RnM (LMatch Name, FreeVars)
+rnMatch ctxt = wrapLocFstM (rnMatch' ctxt)
+
+rnMatch' ctxt match@(Match pats maybe_rhs_sig grhss)
+ =
+ -- Deal with the rhs type signature
+ bindPatSigTyVarsFV rhs_sig_tys $
+ doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
+ (case maybe_rhs_sig of
+ Nothing -> returnM (Nothing, emptyFVs)
+ Just ty | opt_GlasgowExts -> rnHsTypeFVs doc_sig ty `thenM` \ (ty', ty_fvs) ->
+ returnM (Just ty', ty_fvs)
+ | otherwise -> addLocErr ty patSigErr `thenM_`
+ returnM (Nothing, emptyFVs)
+ ) `thenM` \ (maybe_rhs_sig', ty_fvs) ->
+
+ -- Now the main event
+ rnPatsAndThen ctxt pats $ \ pats' ->
+ rnGRHSs ctxt grhss `thenM` \ (grhss', grhss_fvs) ->
+
+ returnM (Match pats' maybe_rhs_sig' grhss', grhss_fvs `plusFV` ty_fvs)
+ -- The bindPatSigTyVarsFV and rnPatsAndThen will remove the bound FVs
+ where
+ rhs_sig_tys = case maybe_rhs_sig of
+ Nothing -> []
+ Just ty -> [ty]
+ doc_sig = text "In a result type-signature"
\end{code}
%************************************************************************
%* *
-\subsubsection[dep-Sigs]{Signatures (and user-pragmas for values)}
+\subsubsection{Guarded right-hand sides (GRHSs)}
%* *
%************************************************************************
-@rnBindSigs@ checks for: (a)~more than one sig for one thing;
-(b)~signatures given for things not bound here; (c)~with suitably
-flaggery, that all top-level things have type signatures.
-
\begin{code}
-rnBindSigs :: Bool -- True <=> top-level binders
- -> [RdrName] -- Binders for this decl group
- -> [RdrNameSig]
- -> RnM_Fixes s [RenamedSig] -- List of Sig constructors
-
-rnBindSigs is_toplev binder_occnames sigs
- =
- -- Rename the signatures
- -- Will complain about sigs for variables not in this group
- mapRn rename_sig sigs `thenRn` \ sigs_maybe ->
- let
- sigs' = catMaybes sigs_maybe
+rnGRHSs :: HsMatchContext Name -> GRHSs RdrName -> RnM (GRHSs Name, FreeVars)
- -- Discard unbound ones we've already complained about, so we
- -- complain about duplicate ones.
+rnGRHSs ctxt (GRHSs grhss binds)
+ = rnLocalBindsAndThen binds $ \ binds' ->
+ mapFvRn (rnGRHS ctxt) grhss `thenM` \ (grhss', fvGRHSs) ->
+ returnM (GRHSs grhss' binds', fvGRHSs)
- (goodies, dups) = removeDups compare (filter (\ x -> not_unbound x && not_main x) sigs')
- in
- mapRn (addErrRn . dupSigDeclErr) dups `thenRn_`
+rnGRHS :: HsMatchContext Name -> LGRHS RdrName -> RnM (LGRHS Name, FreeVars)
+rnGRHS ctxt = wrapLocFstM (rnGRHS' ctxt)
- getSrcLocRn `thenRn` \ locn ->
+rnGRHS' ctxt (GRHS guards rhs)
+ = do { opt_GlasgowExts <- doptM Opt_GlasgowExts
+ ; ((guards', rhs'), fvs) <- rnStmts (PatGuard ctxt) guards $
+ rnLExpr rhs
- (if (is_toplev && opt_SigsRequired) then
- let
- sig_frees = catMaybes (map (sig_free sigs) binder_occnames)
- in
- mapRn (addErrRn . missingSigErr locn) sig_frees
- else
- returnRn []
- ) `thenRn_`
+ ; checkM (opt_GlasgowExts || is_standard_guard guards')
+ (addWarn (nonStdGuardErr guards'))
- returnRn sigs' -- bad ones and all:
- -- we need bindings of *some* sort for every name
+ ; return (GRHS guards' rhs', fvs) }
where
- rename_sig (Sig v ty pragmas src_loc)
- = pushSrcLocRn src_loc $
- if not (v `elem` binder_occnames) then
- addErrRn (unknownSigDeclErr "type signature" v src_loc) `thenRn_`
- returnRn Nothing
- else
- lookupValue v `thenRn` \ new_v ->
- rnPolyType nullTyVarNamesEnv ty `thenRn` \ new_ty ->
-
- ASSERT(isNoGenPragmas pragmas)
- returnRn (Just (Sig new_v new_ty noGenPragmas src_loc))
-
- -- and now, the various flavours of value-modifying user-pragmas:
-
- rename_sig (SpecSig v ty using src_loc)
- = pushSrcLocRn src_loc $
- if not (v `elem` binder_occnames) then
- addErrRn (unknownSigDeclErr "SPECIALIZE pragma" v src_loc) `thenRn_`
- returnRn Nothing
- else
- lookupValue v `thenRn` \ new_v ->
- rnPolyType nullTyVarNamesEnv ty `thenRn` \ new_ty ->
- rn_using using `thenRn` \ new_using ->
- returnRn (Just (SpecSig new_v new_ty new_using src_loc))
- where
- rn_using Nothing = returnRn Nothing
- rn_using (Just x) = lookupValue x `thenRn` \ new_x ->
- returnRn (Just new_x)
-
- rename_sig (InlineSig v src_loc)
- = pushSrcLocRn src_loc $
- if not (v `elem` binder_occnames) then
- addErrRn (unknownSigDeclErr "INLINE pragma" v src_loc) `thenRn_`
- returnRn Nothing
- else
- lookupValue v `thenRn` \ new_v ->
- returnRn (Just (InlineSig new_v src_loc))
-
- rename_sig (DeforestSig v src_loc)
- = pushSrcLocRn src_loc $
- if not (v `elem` binder_occnames) then
- addErrRn (unknownSigDeclErr "DEFOREST pragma" v src_loc) `thenRn_`
- returnRn Nothing
- else
- lookupValue v `thenRn` \ new_v ->
- returnRn (Just (DeforestSig new_v src_loc))
-
- rename_sig (MagicUnfoldingSig v str src_loc)
- = pushSrcLocRn src_loc $
- if not (v `elem` binder_occnames) then
- addErrRn (unknownSigDeclErr "MAGIC_UNFOLDING pragma" v src_loc) `thenRn_`
- returnRn Nothing
- else
- lookupValue v `thenRn` \ new_v ->
- returnRn (Just (MagicUnfoldingSig new_v str src_loc))
-
- not_unbound, not_main :: RenamedSig -> Bool
-
- not_unbound (Sig n _ _ _) = not (isRnUnbound n)
- not_unbound (SpecSig n _ _ _) = not (isRnUnbound n)
- not_unbound (InlineSig n _) = not (isRnUnbound n)
- not_unbound (DeforestSig n _) = not (isRnUnbound n)
- not_unbound (MagicUnfoldingSig n _ _) = not (isRnUnbound n)
-
- not_main (Sig n _ _ _) = let str = getLocalName n in
- not (str == SLIT("main") || str == SLIT("mainPrimIO"))
- not_main _ = True
-
- -------------------------------------
- sig_free :: [RdrNameSig] -> RdrName -> Maybe RdrName
- -- Return "Just x" if "x" has no type signature in
- -- sigs. Nothing, otherwise.
-
- sig_free [] ny = Just ny
- sig_free (Sig nx _ _ _ : rest) ny
- = if (nx == ny) then Nothing else sig_free rest ny
- sig_free (_ : rest) ny = sig_free rest ny
-
- -------------------------------------
- compare :: RenamedSig -> RenamedSig -> TAG_
- compare (Sig n1 _ _ _) (Sig n2 _ _ _) = n1 `cmp` n2
- compare (InlineSig n1 _) (InlineSig n2 _) = n1 `cmp` n2
- compare (MagicUnfoldingSig n1 _ _) (MagicUnfoldingSig n2 _ _) = n1 `cmp` n2
- compare (SpecSig n1 ty1 _ _) (SpecSig n2 ty2 _ _)
- = -- may have many specialisations for one value;
- -- but not ones that are exactly the same...
- thenCmp (n1 `cmp` n2) (cmpPolyType cmp ty1 ty2)
-
- compare other_1 other_2 -- tags *must* be different
- = let tag1 = tag other_1
- tag2 = tag other_2
- in
- if tag1 _LT_ tag2 then LT_ else GT_
-
- tag (Sig n1 _ _ _) = (ILIT(1) :: FAST_INT)
- tag (SpecSig n1 _ _ _) = ILIT(2)
- tag (InlineSig n1 _) = ILIT(3)
- tag (MagicUnfoldingSig n1 _ _) = ILIT(4)
- tag (DeforestSig n1 _) = ILIT(5)
- tag _ = panic# "tag(RnBinds)"
+ -- Standard Haskell 1.4 guards are just a single boolean
+ -- expression, rather than a list of qualifiers as in the
+ -- Glasgow extension
+ is_standard_guard [] = True
+ is_standard_guard [L _ (ExprStmt _ _ _)] = True
+ is_standard_guard other = False
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-dupSigDeclErr sigs
- = let
- undup_sigs = fst (removeDups cmp_sig sigs)
- in
- addErrLoc locn1
- ("more than one "++what_it_is++"\n\thas been given for these variables") ( \ sty ->
- ppAboves (map (ppr sty) undup_sigs) )
+dupSigDeclErr sigs@(L loc sig : _)
+ = addErrAt loc $
+ vcat [ptext SLIT("Duplicate") <+> what_it_is <> colon,
+ nest 2 (vcat (map ppr_sig sigs))]
+ where
+ what_it_is = hsSigDoc sig
+ ppr_sig (L loc sig) = ppr loc <> colon <+> ppr sig
+
+unknownSigErr (L loc sig)
+ = addErrAt loc $
+ sep [ptext SLIT("Misplaced") <+> what_it_is <> colon, ppr sig]
where
- (what_it_is, locn1)
- = case (head sigs) of
- Sig _ _ _ loc -> ("type signature",loc)
- ClassOpSig _ _ _ loc -> ("class-method type signature", loc)
- SpecSig _ _ _ loc -> ("SPECIALIZE pragma",loc)
- InlineSig _ loc -> ("INLINE pragma",loc)
- MagicUnfoldingSig _ _ loc -> ("MAGIC_UNFOLDING pragma",loc)
-
- cmp_sig a b = get_name a `cmp` get_name b
-
- get_name (Sig n _ _ _) = n
- get_name (ClassOpSig n _ _ _) = n
- get_name (SpecSig n _ _ _) = n
- get_name (InlineSig n _) = n
- get_name (MagicUnfoldingSig n _ _) = n
-
-------------------------
-methodBindErr mbind locn
- = addErrLoc locn "Can't handle multiple methods defined by one pattern binding"
- (\ sty -> ppr sty mbind)
-
---------------------------
-missingSigErr locn var
- = addShortErrLocLine locn ( \ sty ->
- ppBesides [ppStr "a definition but no type signature for `",
- ppr sty var,
- ppStr "'."])
-
---------------------------------
-unknownSigDeclErr flavor var locn
- = addShortErrLocLine locn ( \ sty ->
- ppBesides [ppStr flavor, ppStr " but no definition for `",
- ppr sty var,
- ppStr "'."])
+ what_it_is = hsSigDoc sig
+
+missingSigWarn var
+ = addWarnAt (mkSrcSpan loc loc) $
+ sep [ptext SLIT("Definition but no type signature for"), quotes (ppr var)]
+ where
+ loc = nameSrcLoc var -- TODO: make a proper span
+
+methodBindErr mbind
+ = hang (ptext SLIT("Pattern bindings (except simple variables) not allowed in instance declarations"))
+ 2 (ppr mbind)
+
+bindsInHsBootFile mbinds
+ = hang (ptext SLIT("Bindings in hs-boot files are not allowed"))
+ 2 (ppr mbinds)
+
+nonStdGuardErr guards
+ = hang (ptext SLIT("accepting non-standard pattern guards (-fglasgow-exts to suppress this message)"))
+ 4 (interpp'SP guards)
\end{code}
projects / ghc-hetmet.git / blobdiff