RnBinds.lhs 23 KB
 simonmar committed Jun 17, 1999 1 2 3 4 5 6 7 8 9 10 11 12 % % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[RnBinds]{Renaming and dependency analysis of bindings} This module does renaming and dependency analysis on value bindings in the abstract syntax. It does {\em not} do cycle-checks on class or type-synonym declarations; those cannot be done at this stage because they may be affected by renaming (which isn't fully worked out yet). \begin{code} module RnBinds (  simonpj committed Jul 19, 2005 13 14  rnTopBinds, rnLocalBindsAndThen, rnValBindsAndThen, rnValBinds, trimWith,  simonpj@microsoft.com committed Jun 12, 2006 15  rnMethodBinds, renameSigs, mkSigTvFn,  simonpj committed Jul 19, 2005 16  rnMatchGroup, rnGRHSs  simonmar committed Jun 17, 1999 17 18 19 20  ) where #include "HsVersions.h"  simonpj committed Jul 19, 2005 21 import {-# SOURCE #-} RnExpr( rnLExpr, rnStmts )  simonmar committed Jun 17, 1999 22 23 24 25  import HsSyn import RdrHsSyn import RnHsSyn  simonpj committed Sep 13, 2002 26 import TcRnMonad  simonpj committed Jul 19, 2005 27 28 import RnTypes ( rnHsSigType, rnLHsType, rnHsTypeFVs, rnLPat, rnPatsAndThen, patSigErr, checkPrecMatch )  simonmar committed Dec 10, 2003 29 import RnEnv ( bindLocatedLocalsRn, lookupLocatedBndrRn,  simonpj committed Jul 19, 2005 30  lookupLocatedInstDeclBndr, newIPNameRn,  simonpj@microsoft.com committed May 08, 2006 31  lookupLocatedSigOccRn, bindPatSigTyVarsFV,  simonpj committed Dec 22, 2004 32  bindLocalFixities, bindSigTyVarsFV,  simonpj committed Oct 03, 2000 33  warnUnusedLocalBinds, mapFvRn, extendTyVarEnvFVRn,  simonmar committed Jun 17, 1999 34  )  simonmar committed Mar 18, 2005 35 import DynFlags ( DynFlag(..) )  simonmar committed Feb 26, 2001 36 import Name ( Name, nameOccName, nameSrcLoc )  simonpj committed Jul 19, 2005 37 import NameEnv  simonmar committed Jun 17, 1999 38 import NameSet  simonpj committed Oct 09, 2003 39 import PrelNames ( isUnboundName )  simonpj committed Oct 03, 2000 40 import RdrName ( RdrName, rdrNameOcc )  simonmar committed Dec 10, 2003 41 import SrcLoc ( mkSrcSpan, Located(..), unLoc )  simonpj committed Jul 19, 2005 42 import ListSetOps ( findDupsEq )  simonpj committed Aug 10, 2005 43 44 import BasicTypes ( RecFlag(..) ) import Digraph ( SCC(..), stronglyConnComp )  simonmar committed Dec 10, 2003 45 import Bag  simonmar committed Jun 17, 1999 46 import Outputable  simonpj@microsoft.com committed May 08, 2006 47 import Maybes ( orElse )  simonpj committed Aug 12, 2005 48 import Util ( filterOut )  simonmar committed Dec 10, 2003 49 import Monad ( foldM )  simonmar committed Jun 17, 1999 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 \end{code} -- ToDo: Put the annotations into the monad, so that they arrive in the proper -- place and can be used when complaining. The code tree received by the function @rnBinds@ contains definitions in where-clauses which are all apparently mutually recursive, but which may not really depend upon each other. For example, in the top level program \begin{verbatim} f x = y where a = x y = x \end{verbatim} the definitions of @a@ and @y@ do not depend on each other at all. Unfortunately, the typechecker cannot always check such definitions. \footnote{Mycroft, A. 1984. Polymorphic type schemes and recursive definitions. In Proceedings of the International Symposium on Programming, Toulouse, pp. 217-39. LNCS 167. Springer Verlag.} However, the typechecker usually can check definitions in which only the strongly connected components have been collected into recursive bindings. This is precisely what the function @rnBinds@ does. ToDo: deal with case where a single monobinds binds the same variable twice. 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). %************************************************************************ %* * %* naming conventions * %* * %************************************************************************ \subsection[name-conventions]{Name conventions} The basic algorithm involves walking over the tree and returning a tuple containing the new tree plus its free variables. Some functions, such as those walking polymorphic bindings (HsBinds) and qualifier lists in list comprehensions (@Quals@), return the variables bound in local environments. These are then used to calculate the free variables of the expression evaluated in these environments. Conventions for variable names are as follows: \begin{itemize} \item new code is given a prime to distinguish it from the old. \item a set of variables defined in @Exp@ is written @dvExp@ \item a set of variables free in @Exp@ is written @fvExp@ \end{itemize} %************************************************************************ %* *  simonmar committed Dec 10, 2003 108 %* analysing polymorphic bindings (HsBindGroup, HsBind)  simonmar committed Jun 17, 1999 109 110 111 112 113 114 115 116 117 118 119 %* * %************************************************************************ \subsubsection[dep-HsBinds]{Polymorphic bindings} Non-recursive expressions are reconstructed without any changes at top level, although their component expressions may have to be altered. However, non-recursive expressions are currently not expected as \Haskell{} programs, and this code should not be executed. Monomorphic bindings contain information that is returned in a tuple  simonpj committed Sep 27, 2002 120 (a @FlatMonoBinds@) containing:  simonmar committed Jun 17, 1999 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157  \begin{enumerate} \item a unique @Int@ that serves as the vertex tag'' for this binding. \item the name of a function or the names in a pattern. These are a set referred to as @dvLhs@, the defined variables of the left hand side. \item the free variables of the body. These are referred to as @fvBody@. \item the definition's actual code. This is referred to as just @code@. \end{enumerate} The function @nonRecDvFv@ returns two sets of variables. The first is the set of variables defined in the set of monomorphic bindings, while the second is the set of free variables in those bindings. The set of variables defined in a non-recursive binding is just the union of all of them, as @union@ removes duplicates. However, the free variables in each successive set of cumulative bindings is the union of those in the previous set plus those of the newest binding after the defined variables of the previous set have been removed. @rnMethodBinds@ deals only with the declarations in class and instance declarations. It expects only to see @FunMonoBind@s, and it expects the global environment to contain bindings for the binders (which are all class operations). %************************************************************************ %* * \subsubsection{ Top-level bindings} %* * %************************************************************************  simonpj committed Sep 13, 2002 158 @rnTopMonoBinds@ assumes that the environment already  simonmar committed Jun 17, 1999 159 160 161 contains bindings for the binders of this particular binding. \begin{code}  simonpj committed Jul 19, 2005 162 rnTopBinds :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)  simonpj committed Sep 26, 2002 163   simonpj committed Feb 21, 2003 164 -- The binders of the binding are in scope already;  simonpj committed Oct 09, 2003 165 -- the top level scope resolution does that  simonpj committed Sep 27, 2002 166   simonpj committed Jul 19, 2005 167 rnTopBinds binds  simonpj committed Jan 27, 2005 168  = do { is_boot <- tcIsHsBoot  simonpj committed Jul 19, 2005 169 170 171 172  ; if is_boot then rnTopBindsBoot binds else rnTopBindsSrc binds } rnTopBindsBoot :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)  simonpj committed Jan 27, 2005 173 174 -- A hs-boot file has no bindings. -- Return a single HsBindGroup with empty binds and renamed signatures  simonpj committed Jul 19, 2005 175 rnTopBindsBoot (ValBindsIn mbinds sigs)  simonpj committed Jan 27, 2005 176  = do { checkErr (isEmptyLHsBinds mbinds) (bindsInHsBootFile mbinds)  simonpj committed Jul 19, 2005 177  ; sigs' <- renameSigs okHsBootSig sigs  simonpj committed Aug 11, 2005 178  ; return (ValBindsOut [] sigs', usesOnly (hsSigsFVs sigs')) }  simonpj committed Jul 19, 2005 179 180 181  rnTopBindsSrc :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses) rnTopBindsSrc binds@(ValBindsIn mbinds _)  simonpj@microsoft.com committed Jan 25, 2006 182  = do { (binds', dus) <- rnValBinds noTrim binds  simonpj committed Jul 19, 2005 183 184  -- Warn about missing signatures,  simonpj committed Aug 10, 2005 185  ; let { ValBindsOut _ sigs' = binds'  simonpj committed Oct 27, 2005 186  ; ty_sig_vars = mkNameSet [ unLoc n | L _ (TypeSig n _) <- sigs']  simonpj committed Jul 19, 2005 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233  ; 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} %********************************************************* %* * HsLocalBinds %* * %********************************************************* \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 $\ val_binds' -> thing_inside (HsValBinds val_binds') rnLocalBindsAndThen (HsIPBinds binds) thing_inside = rnIPBinds binds thenM \ (binds',fv_binds) -> thing_inside (HsIPBinds binds') thenM \ (thing, fvs_thing) -> returnM (thing, fvs_thing plusFV fv_binds) ------------- rnIPBinds (IPBinds ip_binds _no_dict_binds) = do { (ip_binds', fvs_s) <- mapAndUnzipM (wrapLocFstM rnIPBind) ip_binds ; return (IPBinds ip_binds' emptyLHsBinds, plusFVs fvs_s) } rnIPBind (IPBind n expr) = newIPNameRn n thenM \ name -> rnLExpr expr thenM \ (expr',fvExpr) -> return (IPBind name expr', fvExpr)  simonmar committed Jun 17, 1999 234 235 \end{code}  simonpj committed Sep 27, 2002 236   simonmar committed Jun 17, 1999 237 238 %************************************************************************ %* *  simonpj committed Jul 19, 2005 239  ValBinds  simonmar committed Jun 17, 1999 240 241 242 243 %* * %************************************************************************ \begin{code}  simonpj committed Jul 19, 2005 244 245 246 rnValBindsAndThen :: HsValBinds RdrName -> (HsValBinds Name -> RnM (result, FreeVars)) -> RnM (result, FreeVars)  simonpj committed Sep 27, 2002 247   simonpj committed Jul 19, 2005 248 rnValBindsAndThen binds@(ValBindsIn mbinds sigs) thing_inside  simonpj committed Sep 27, 2002 249 250  = -- Extract all the binders in this group, and extend the -- current scope, inventing new names for the new binders  simonmar committed Jun 17, 1999 251  -- This also checks that the names form a set  simonpj committed Jul 19, 2005 252  bindLocatedLocalsRn doc mbinders_w_srclocs$ \ bndrs ->  simonpj committed Mar 09, 2000 253   simonpj committed Sep 27, 2002 254  -- Then install local fixity declarations  simonpj committed Mar 09, 2000 255  -- Notice that they scope over thing_inside too  simonmar committed Dec 10, 2003 256  bindLocalFixities [sig | L _ (FixSig sig) <- sigs ] $ simonpj committed Mar 09, 2000 257   simonpj committed Sep 27, 2002 258  -- Do the business  simonpj committed Jul 19, 2005 259  rnValBinds (trimWith bndrs) binds thenM \ (binds, bind_dus) ->  simonmar committed Jun 17, 1999 260   simonpj committed Sep 27, 2002 261  -- Now do the "thing inside"  simonpj committed Oct 09, 2002 262  thing_inside binds thenM \ (result,result_fvs) ->  simonpj committed Sep 27, 2002 263 264  -- Final error checking  simonmar committed Jun 17, 1999 265  let  simonpj committed Aug 10, 2005 266  all_uses = duUses bind_dus plusFV result_fvs  simonpj committed Jul 19, 2005 267 268  -- duUses: It's important to return all the uses, not the 'real uses' -- used for warning about unused bindings. Otherwise consider:  simonpj committed Feb 21, 2003 269  -- x = 3  simonpj committed Oct 30, 2003 270  -- y = let p = x in 'x' -- NB: p not used  simonpj committed Feb 21, 2003 271 272 273  -- 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  simonpj committed Aug 10, 2005 274 275 276 277 278 279  unused_bndrs = [ b | b <- bndrs, not (b elemNameSet all_uses)] in warnUnusedLocalBinds unused_bndrs thenM_ returnM (result, delListFromNameSet all_uses bndrs)  simonmar committed Jun 17, 1999 280  where  simonmar committed Dec 10, 2003 281  mbinders_w_srclocs = collectHsBindLocatedBinders mbinds  simonpj committed Sep 27, 2002 282  doc = text "In the binding group for:"  simonmar committed Dec 10, 2003 283  <+> pprWithCommas ppr (map unLoc mbinders_w_srclocs)  simonpj committed Feb 21, 2003 284   simonpj committed Jul 19, 2005 285 286 287 288 --------------------- rnValBinds :: (FreeVars -> FreeVars) -> HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)  simonpj committed Feb 21, 2003 289 290 -- Assumes the binders of the binding are in scope already  simonpj committed Jul 19, 2005 291 292 293 rnValBinds trim (ValBindsIn mbinds sigs) = do { sigs' <- rename_sigs sigs  simonpj committed Aug 10, 2005 294 295 296 297  ; binds_w_dus <- mapBagM (rnBind (mkSigTvFn sigs') trim) mbinds ; let (binds', bind_dus) = depAnalBinds binds_w_dus  simonpj committed Aug 11, 2005 298 299  -- We do the check-sigs after renaming the bindings, -- so that we have convenient access to the binders  simonpj committed Aug 10, 2005 300 301 302 303 304 305 306 307 308  ; check_sigs (okBindSig (duDefs bind_dus)) sigs' ; return (ValBindsOut binds' sigs', usesOnly (hsSigsFVs sigs') plusDU bind_dus) } --------------------- depAnalBinds :: Bag (LHsBind Name, [Name], Uses) -> ([(RecFlag, LHsBinds Name)], DefUses)  simonpj committed Aug 11, 2005 309 310 -- Dependency analysis; this is important so that -- unused-binding reporting is accurate  simonpj committed Aug 10, 2005 311 312 313 314 315 316 317 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 ..]  Simon Marlow committed Mar 02, 2006 318 319  edges = [ (node, key, [key | n <- nameSetToList uses, Just key <- [lookupNameEnv key_map n] ])  simonpj committed Aug 10, 2005 320  | (node@(_,_,uses), key) <- keyd_nodes ]  simonpj committed Jul 19, 2005 321   simonpj committed Aug 10, 2005 322 323 324  key_map :: NameEnv Int -- Which binding it comes from key_map = mkNameEnv [(bndr, key) | ((_, bndrs, _), key) <- keyd_nodes , bndr <- bndrs ]  simonpj committed Jul 19, 2005 325   simonpj committed Aug 10, 2005 326 327  get_binds (AcyclicSCC (bind, _, _)) = (NonRecursive, unitBag bind) get_binds (CyclicSCC binds_w_dus) = (Recursive, listToBag [b | (b,d,u) <- binds_w_dus])  simonpj committed Jul 19, 2005 328   simonpj committed Aug 10, 2005 329 330 331 332 333  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]  simonpj committed Jul 19, 2005 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353  --------------------- -- 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 []  simonpj committed May 25, 2000 354  where  simonpj committed Jul 19, 2005 355 356  env :: NameEnv [Name] env = mkNameEnv [ (name, map hsLTyVarName ltvs)  simonpj committed Oct 27, 2005 357 358  | L _ (TypeSig (L _ name) (L _ (HsForAllTy Explicit ltvs _ _))) <- sigs]  simonpj committed Jul 19, 2005 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373  -- 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  simonpj committed Aug 10, 2005 374 375  -> LHsBind RdrName -> RnM (LHsBind Name, [Name], Uses)  simonpj@microsoft.com committed Jan 25, 2006 376 rnBind sig_fn trim (L loc (PatBind { pat_lhs = pat, pat_rhs = grhss }))  simonpj committed Aug 10, 2005 377 378  = setSrcSpan loc$ do { (pat', pat_fvs) <- rnLPat pat  simonpj committed Jul 19, 2005 379 380 381 382 383 384  ; let bndrs = collectPatBinders pat' ; (grhss', fvs) <- bindSigTyVarsFV (concatMap sig_fn bndrs) $rnGRHSs PatBindRhs grhss  simonpj@microsoft.com committed Jan 25, 2006 385 386 387  ; return (L loc (PatBind { pat_lhs = pat', pat_rhs = grhss', pat_rhs_ty = placeHolderType, bind_fvs = trim fvs }), bndrs, pat_fvs plusFV fvs) }  simonpj committed Jul 19, 2005 388   simonpj@microsoft.com committed Jan 25, 2006 389 rnBind sig_fn trim (L loc (FunBind { fun_id = name, fun_infix = inf, fun_matches = matches }))  simonpj committed Aug 10, 2005 390 391 392  = setSrcSpan loc$ do { new_name <- lookupLocatedBndrRn name ; let plain_name = unLoc new_name  simonpj committed Jul 19, 2005 393 394 395 396 397 398  ; (matches', fvs) <- bindSigTyVarsFV (sig_fn plain_name) $rnMatchGroup (FunRhs plain_name) matches ; checkPrecMatch inf plain_name matches'  simonpj@microsoft.com committed Jan 25, 2006 399  ; return (L loc (FunBind { fun_id = new_name, fun_infix = inf, fun_matches = matches',  simonpj@microsoft.com committed Sep 29, 2006 400  bind_fvs = trim fvs, fun_co_fn = idHsWrapper }),  simonpj@microsoft.com committed Jan 25, 2006 401  [plain_name], fvs)  simonpj committed Jul 19, 2005 402  }  simonmar committed Jun 17, 1999 403 404 405 406 \end{code} @rnMethodBinds@ is used for the method bindings of a class and an instance  simonmar committed Dec 10, 2003 407 declaration. Like @rnBinds@ but without dependency analysis.  simonmar committed Jun 17, 1999 408 409 410 411 412 413 414 415 416 417 418 419 420 421  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. \begin{code}  simonpj committed Dec 06, 2001 422 rnMethodBinds :: Name -- Class name  simonpj@microsoft.com committed Jun 12, 2006 423  -> (Name -> [Name]) -- Signature tyvar function  simonpj committed Dec 06, 2001 424  -> [Name] -- Names for generic type variables  simonpj committed Sep 30, 2004 425  -> LHsBinds RdrName  simonmar committed Dec 10, 2003 426  -> RnM (LHsBinds Name, FreeVars)  simonmar committed Jun 17, 1999 427   simonpj@microsoft.com committed Jun 12, 2006 428 rnMethodBinds cls sig_fn gen_tyvars binds  simonmar committed Dec 10, 2003 429 430  = foldM do_one (emptyBag,emptyFVs) (bagToList binds) where do_one (binds,fvs) bind = do  simonpj@microsoft.com committed Jun 12, 2006 431  (bind', fvs_bind) <- rnMethodBind cls sig_fn gen_tyvars bind  simonmar committed Dec 10, 2003 432  return (bind' unionBags binds, fvs_bind plusFV fvs)  simonmar committed Jun 17, 1999 433   simonpj@microsoft.com committed Jun 12, 2006 434 435 436 437 438 rnMethodBind cls sig_fn 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  simonmar committed Jun 17, 1999 439 440  -- We use the selector name as the binder  simonpj@microsoft.com committed Jun 12, 2006 441  bindSigTyVarsFV (sig_fn plain_name) $ simonmar committed Dec 10, 2003 442  mapFvRn (rn_match plain_name) matches thenM \ (new_matches, fvs) ->  simonpj committed Sep 30, 2004 443 444 445 446  let new_group = MatchGroup new_matches placeHolderType in checkPrecMatch inf plain_name new_group thenM_  simonpj@microsoft.com committed Jan 25, 2006 447  returnM (unitBag (L loc (FunBind { fun_id = sel_name, fun_infix = inf, fun_matches = new_group,  simonpj@microsoft.com committed Sep 29, 2006 448  bind_fvs = fvs, fun_co_fn = idHsWrapper })),  simonpj@microsoft.com committed Jan 25, 2006 449  fvs addOneFV plain_name)  simonpj committed Jul 19, 2005 450  -- The 'fvs' field isn't used for method binds  simonpj committed Oct 03, 2000 451  where  simonpj committed Sep 30, 2004 452 453  -- Truly gruesome; bring into scope the correct members of the generic -- type variables. See comments in RnSource.rnSourceDecl(ClassDecl)  simonmar committed Dec 10, 2003 454  rn_match sel_name match@(L _ (Match (L _ (TypePat ty) : _) _ _))  simonpj committed Sep 27, 2002 455 456  = extendTyVarEnvFVRn gen_tvs$ rnMatch (FunRhs sel_name) match  simonpj committed Oct 03, 2000 457  where  simonmar committed Dec 10, 2003 458  tvs = map (rdrNameOcc.unLoc) (extractHsTyRdrTyVars ty)  simonpj committed Oct 03, 2000 459 460  gen_tvs = [tv | tv <- gen_tyvars, nameOccName tv elem tvs]  simonpj committed Sep 27, 2002 461  rn_match sel_name match = rnMatch (FunRhs sel_name) match  simonmar committed Dec 10, 2003 462   simonmar committed Jun 17, 1999 463 464  -- Can't handle method pattern-bindings which bind multiple methods.  simonpj@microsoft.com committed Jun 12, 2006 465 rnMethodBind cls sig_fn gen_tyvars mbind@(L loc (PatBind other_pat _ _ _))  simonmar committed Dec 10, 2003 466 467  = addLocErr mbind methodBindErr thenM_ returnM (emptyBag, emptyFVs)  simonmar committed Jun 17, 1999 468 469 470 \end{code}  chak@cse.unsw.edu.au. committed Sep 15, 2006 471   simonmar committed Jun 17, 1999 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 %************************************************************************ %* * \subsubsection[dep-Sigs]{Signatures (and user-pragmas for values)} %* * %************************************************************************ @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}  simonpj committed Jul 19, 2005 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 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  simonmar committed Jun 17, 1999 506 507  -- Check for (a) duplicate signatures -- (b) signatures for things not in this group  simonpj committed Aug 12, 2005 508 509  = do { mappM_ unknownSigErr (filter (not . ok_sig) sigs') ; mappM_ dupSigDeclErr (findDupsEq eqHsSig sigs') }  simonpj committed Sep 27, 2002 510  where  simonpj committed Jul 25, 2005 511  -- Don't complain about an unbound name again  simonpj committed Aug 12, 2005 512 513 514 515  sigs' = filterOut bad_name sigs bad_name sig = case sigName sig of Just n -> isUnboundName n other -> False  simonpj committed Jul 25, 2005 516   simonpj committed Jul 19, 2005 517 -- We use lookupLocatedSigOccRn in the signatures, which is a little bit unsatisfactory  simonmar committed Jun 17, 1999 518 519 520 521 522 523 524 525 -- 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.  simonpj committed Sep 13, 2002 526 renameSig :: Sig RdrName -> RnM (Sig Name)  simonpj committed Oct 09, 2003 527 -- FixitSig is renamed elsewhere.  simonpj committed Oct 27, 2005 528 renameSig (TypeSig v ty)  simonmar committed Dec 10, 2003 529  = lookupLocatedSigOccRn v thenM \ new_v ->  simonpj committed Sep 13, 2002 530  rnHsSigType (quotes (ppr v)) ty thenM \ new_ty ->  simonpj committed Oct 27, 2005 531  returnM (TypeSig new_v new_ty)  simonmar committed Jun 17, 1999 532   simonmar committed Dec 10, 2003 533 534 535 renameSig (SpecInstSig ty) = rnLHsType (text "A SPECIALISE instance pragma") ty thenM \ new_ty -> returnM (SpecInstSig new_ty)  simonmar committed Jun 17, 1999 536   simonpj committed Oct 27, 2005 537 renameSig (SpecSig v ty inl)  simonmar committed Dec 10, 2003 538  = lookupLocatedSigOccRn v thenM \ new_v ->  simonpj committed Sep 13, 2002 539  rnHsSigType (quotes (ppr v)) ty thenM \ new_ty ->  simonpj committed Oct 27, 2005 540  returnM (SpecSig new_v new_ty inl)  simonmar committed Jun 17, 1999 541   simonpj committed Oct 27, 2005 542 renameSig (InlineSig v s)  simonmar committed Dec 10, 2003 543  = lookupLocatedSigOccRn v thenM \ new_v ->  simonpj committed Oct 27, 2005 544  returnM (InlineSig new_v s)  simonmar committed Jun 17, 1999 545 546 547 \end{code}  simonpj committed Jul 19, 2005 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 ************************************************************************ * * \subsection{Match} * * ************************************************************************ \begin{code} 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{Guarded right-hand sides (GRHSs)} %* * %************************************************************************ \begin{code} rnGRHSs :: HsMatchContext Name -> GRHSs RdrName -> RnM (GRHSs Name, FreeVars) rnGRHSs ctxt (GRHSs grhss binds) = rnLocalBindsAndThen binds $\ binds' -> mapFvRn (rnGRHS ctxt) grhss thenM \ (grhss', fvGRHSs) -> returnM (GRHSs grhss' binds', fvGRHSs) rnGRHS :: HsMatchContext Name -> LGRHS RdrName -> RnM (LGRHS Name, FreeVars) rnGRHS ctxt = wrapLocFstM (rnGRHS' ctxt) rnGRHS' ctxt (GRHS guards rhs) = do { opt_GlasgowExts <- doptM Opt_GlasgowExts ; ((guards', rhs'), fvs) <- rnStmts (PatGuard ctxt) guards$ rnLExpr rhs  simonpj@microsoft.com committed Feb 06, 2006 611 612 613 614  ; checkM (opt_GlasgowExts || is_standard_guard guards') (addWarn (nonStdGuardErr guards'))  simonpj committed Jul 19, 2005 615 616 617 618 619 620 621 622 623 624  ; return (GRHS guards' rhs', fvs) } where -- 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}  simonmar committed Jun 17, 1999 625 626 627 628 629 630 631 %************************************************************************ %* * \subsection{Error messages} %* * %************************************************************************ \begin{code}  simonpj committed Jul 19, 2005 632 dupSigDeclErr sigs@(L loc sig : _)  simonmar committed Dec 10, 2003 633 634  = addErrAt loc $vcat [ptext SLIT("Duplicate") <+> what_it_is <> colon,  simonpj committed Jul 19, 2005 635  nest 2 (vcat (map ppr_sig sigs))]  simonmar committed Jun 17, 1999 636  where  simonmar committed Dec 10, 2003 637 638  what_it_is = hsSigDoc sig ppr_sig (L loc sig) = ppr loc <> colon <+> ppr sig  simonmar committed Jun 17, 1999 639   simonmar committed Dec 10, 2003 640 641 642 unknownSigErr (L loc sig) = addErrAt loc$ sep [ptext SLIT("Misplaced") <+> what_it_is <> colon, ppr sig]  simonmar committed Jun 17, 1999 643  where  simonmar committed Dec 10, 2003 644  what_it_is = hsSigDoc sig  simonmar committed Jun 17, 1999 645 646  missingSigWarn var  simonmar committed Dec 10, 2003 647 648 649 650  = 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  simonmar committed Jun 17, 1999 651 652  methodBindErr mbind  simonpj committed Oct 11, 2004 653  = hang (ptext SLIT("Pattern bindings (except simple variables) not allowed in instance declarations"))  simonpj committed Jan 27, 2005 654 655 656 657 658  2 (ppr mbind) bindsInHsBootFile mbinds = hang (ptext SLIT("Bindings in hs-boot files are not allowed")) 2 (ppr mbinds)  simonpj committed Jul 19, 2005 659   simonpj@microsoft.com committed Feb 06, 2006 660 661 662 nonStdGuardErr guards = hang (ptext SLIT("accepting non-standard pattern guards (-fglasgow-exts to suppress this message)")) 4 (interpp'SP guards)  simonmar committed Jun 17, 1999 663 \end{code}