RnBinds.lhs 23.1 KB
 simonmar committed Jun 17, 1999 1 2 3 4 5 6 7 8 9 10 11 % % (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}  Ian Lynagh committed Sep 03, 2007 12 {-# OPTIONS -w #-}  Ian Lynagh committed Sep 01, 2007 13 14 15 -- The above warning supression flag is a temporary kludge. -- While working on this module you are encouraged to remove it and fix -- any warnings in the module. See  Ian Lynagh committed Sep 04, 2007 16 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings  Ian Lynagh committed Sep 01, 2007 17 18 -- for details  simonmar committed Jun 17, 1999 19 module RnBinds (  simonpj committed Jul 19, 2005 20 21  rnTopBinds, rnLocalBindsAndThen, rnValBindsAndThen, rnValBinds, trimWith,  simonpj@microsoft.com committed Jun 12, 2006 22  rnMethodBinds, renameSigs, mkSigTvFn,  simonpj committed Jul 19, 2005 23  rnMatchGroup, rnGRHSs  simonmar committed Jun 17, 1999 24 25 26 27  ) where #include "HsVersions.h"  simonpj committed Jul 19, 2005 28 import {-# SOURCE #-} RnExpr( rnLExpr, rnStmts )  simonmar committed Jun 17, 1999 29 30 31 32  import HsSyn import RdrHsSyn import RnHsSyn  simonpj committed Sep 13, 2002 33 import TcRnMonad  simonpj committed Jul 19, 2005 34 35 import RnTypes ( rnHsSigType, rnLHsType, rnHsTypeFVs, rnLPat, rnPatsAndThen, patSigErr, checkPrecMatch )  simonmar committed Dec 10, 2003 36 import RnEnv ( bindLocatedLocalsRn, lookupLocatedBndrRn,  David Himmelstrup committed Jun 21, 2007 37  lookupInstDeclBndr, newIPNameRn,  simonpj@microsoft.com committed May 08, 2006 38  lookupLocatedSigOccRn, bindPatSigTyVarsFV,  simonpj committed Dec 22, 2004 39  bindLocalFixities, bindSigTyVarsFV,  simonpj committed Oct 03, 2000 40  warnUnusedLocalBinds, mapFvRn, extendTyVarEnvFVRn,  simonmar committed Jun 17, 1999 41  )  simonmar committed Mar 18, 2005 42 import DynFlags ( DynFlag(..) )  simonpj@microsoft.com committed May 02, 2007 43 import Name  simonpj committed Jul 19, 2005 44 import NameEnv  simonmar committed Jun 17, 1999 45 import NameSet  simonpj committed Oct 09, 2003 46 import PrelNames ( isUnboundName )  simonpj committed Oct 03, 2000 47 import RdrName ( RdrName, rdrNameOcc )  simonpj@microsoft.com committed May 02, 2007 48 import SrcLoc ( Located(..), unLoc )  simonpj committed Jul 19, 2005 49 import ListSetOps ( findDupsEq )  simonpj committed Aug 10, 2005 50 51 import BasicTypes ( RecFlag(..) ) import Digraph ( SCC(..), stronglyConnComp )  simonmar committed Dec 10, 2003 52 import Bag  simonmar committed Jun 17, 1999 53 import Outputable  simonpj@microsoft.com committed May 08, 2006 54 import Maybes ( orElse )  simonpj committed Aug 12, 2005 55 import Util ( filterOut )  simonmar committed Dec 10, 2003 56 import Monad ( foldM )  simonmar committed Jun 17, 1999 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 \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 115 %* analysing polymorphic bindings (HsBindGroup, HsBind)  simonmar committed Jun 17, 1999 116 117 118 119 120 121 122 123 124 125 126 %* * %************************************************************************ \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 127 (a @FlatMonoBinds@) containing:  simonmar committed Jun 17, 1999 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164  \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 165 @rnTopMonoBinds@ assumes that the environment already  simonmar committed Jun 17, 1999 166 167 168 contains bindings for the binders of this particular binding. \begin{code}  simonpj committed Jul 19, 2005 169 rnTopBinds :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)  simonpj committed Sep 26, 2002 170   simonpj committed Feb 21, 2003 171 -- The binders of the binding are in scope already;  simonpj committed Oct 09, 2003 172 -- the top level scope resolution does that  simonpj committed Sep 27, 2002 173   simonpj committed Jul 19, 2005 174 rnTopBinds binds  simonpj committed Jan 27, 2005 175  = do { is_boot <- tcIsHsBoot  simonpj committed Jul 19, 2005 176 177 178 179  ; if is_boot then rnTopBindsBoot binds else rnTopBindsSrc binds } rnTopBindsBoot :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)  simonpj committed Jan 27, 2005 180 181 -- A hs-boot file has no bindings. -- Return a single HsBindGroup with empty binds and renamed signatures  simonpj committed Jul 19, 2005 182 rnTopBindsBoot (ValBindsIn mbinds sigs)  simonpj committed Jan 27, 2005 183  = do { checkErr (isEmptyLHsBinds mbinds) (bindsInHsBootFile mbinds)  simonpj committed Jul 19, 2005 184  ; sigs' <- renameSigs okHsBootSig sigs  simonpj committed Aug 11, 2005 185  ; return (ValBindsOut [] sigs', usesOnly (hsSigsFVs sigs')) }  simonpj committed Jul 19, 2005 186 187  rnTopBindsSrc :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)  188 rnTopBindsSrc binds = rnValBinds noTrim binds  simonpj committed Jul 19, 2005 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 \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 $\ val_binds' -> thing_inside (HsValBinds val_binds') rnLocalBindsAndThen (HsIPBinds binds) thing_inside = rnIPBinds binds thenM \ (binds',fv_binds) -> thing_inside (HsIPBinds binds') thenM \ (thing, fvs_thing) -> returnM (thing, fvs_thing plusFV fv_binds) ------------- rnIPBinds (IPBinds ip_binds _no_dict_binds) = do { (ip_binds', fvs_s) <- mapAndUnzipM (wrapLocFstM rnIPBind) ip_binds ; return (IPBinds ip_binds' emptyLHsBinds, plusFVs fvs_s) } rnIPBind (IPBind n expr) = newIPNameRn n thenM \ name -> rnLExpr expr thenM \ (expr',fvExpr) -> return (IPBind name expr', fvExpr)  simonmar committed Jun 17, 1999 228 229 \end{code}  simonpj committed Sep 27, 2002 230   simonmar committed Jun 17, 1999 231 232 %************************************************************************ %* *  simonpj committed Jul 19, 2005 233  ValBinds  simonmar committed Jun 17, 1999 234 235 236 237 %* * %************************************************************************ \begin{code}  simonpj committed Jul 19, 2005 238 239 240 rnValBindsAndThen :: HsValBinds RdrName -> (HsValBinds Name -> RnM (result, FreeVars)) -> RnM (result, FreeVars)  simonpj committed Sep 27, 2002 241   simonpj committed Jul 19, 2005 242 rnValBindsAndThen binds@(ValBindsIn mbinds sigs) thing_inside  simonpj committed Sep 27, 2002 243 244  = -- Extract all the binders in this group, and extend the -- current scope, inventing new names for the new binders  simonmar committed Jun 17, 1999 245  -- This also checks that the names form a set  simonpj committed Jul 19, 2005 246  bindLocatedLocalsRn doc mbinders_w_srclocs$ \ bndrs ->  simonpj committed Mar 09, 2000 247   simonpj committed Sep 27, 2002 248  -- Then install local fixity declarations  simonpj committed Mar 09, 2000 249  -- Notice that they scope over thing_inside too  simonmar committed Dec 10, 2003 250  bindLocalFixities [sig | L _ (FixSig sig) <- sigs ] $ simonpj committed Mar 09, 2000 251   simonpj committed Sep 27, 2002 252  -- Do the business  simonpj committed Jul 19, 2005 253  rnValBinds (trimWith bndrs) binds thenM \ (binds, bind_dus) ->  simonmar committed Jun 17, 1999 254   simonpj committed Sep 27, 2002 255  -- Now do the "thing inside"  simonpj committed Oct 09, 2002 256  thing_inside binds thenM \ (result,result_fvs) ->  simonpj committed Sep 27, 2002 257 258  -- Final error checking  simonmar committed Jun 17, 1999 259  let  simonpj committed Aug 10, 2005 260  all_uses = duUses bind_dus plusFV result_fvs  simonpj committed Jul 19, 2005 261 262  -- 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 263  -- x = 3  simonpj committed Oct 30, 2003 264  -- y = let p = x in 'x' -- NB: p not used  simonpj committed Feb 21, 2003 265 266 267  -- 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 268 269 270 271 272 273  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 274  where  simonmar committed Dec 10, 2003 275  mbinders_w_srclocs = collectHsBindLocatedBinders mbinds  simonpj committed Sep 27, 2002 276  doc = text "In the binding group for:"  simonmar committed Dec 10, 2003 277  <+> pprWithCommas ppr (map unLoc mbinders_w_srclocs)  simonpj committed Feb 21, 2003 278   simonpj committed Jul 19, 2005 279 280 281 282 --------------------- rnValBinds :: (FreeVars -> FreeVars) -> HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)  simonpj committed Feb 21, 2003 283 284 -- Assumes the binders of the binding are in scope already  simonpj committed Jul 19, 2005 285 286 287 rnValBinds trim (ValBindsIn mbinds sigs) = do { sigs' <- rename_sigs sigs  simonpj committed Aug 10, 2005 288 289 290 291  ; binds_w_dus <- mapBagM (rnBind (mkSigTvFn sigs') trim) mbinds ; let (binds', bind_dus) = depAnalBinds binds_w_dus  simonpj committed Aug 11, 2005 292 293  -- We do the check-sigs after renaming the bindings, -- so that we have convenient access to the binders  simonpj committed Aug 10, 2005 294 295 296 297 298 299 300 301 302  ; 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 303 304 -- Dependency analysis; this is important so that -- unused-binding reporting is accurate  simonpj committed Aug 10, 2005 305 306 307 308 309 310 311 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 312 313  edges = [ (node, key, [key | n <- nameSetToList uses, Just key <- [lookupNameEnv key_map n] ])  simonpj committed Aug 10, 2005 314  | (node@(_,_,uses), key) <- keyd_nodes ]  simonpj committed Jul 19, 2005 315   simonpj committed Aug 10, 2005 316 317 318  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 319   simonpj committed Aug 10, 2005 320 321  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 322   simonpj committed Aug 10, 2005 323 324 325 326 327  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 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347  --------------------- -- 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 348  where  simonpj committed Jul 19, 2005 349 350  env :: NameEnv [Name] env = mkNameEnv [ (name, map hsLTyVarName ltvs)  simonpj committed Oct 27, 2005 351 352  | L _ (TypeSig (L _ name) (L _ (HsForAllTy Explicit ltvs _ _))) <- sigs]  simonpj committed Jul 19, 2005 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367  -- 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 368 369  -> LHsBind RdrName -> RnM (LHsBind Name, [Name], Uses)  simonpj@microsoft.com committed Jan 25, 2006 370 rnBind sig_fn trim (L loc (PatBind { pat_lhs = pat, pat_rhs = grhss }))  simonpj committed Aug 10, 2005 371 372  = setSrcSpan loc$ do { (pat', pat_fvs) <- rnLPat pat  simonpj committed Jul 19, 2005 373 374 375  ; let bndrs = collectPatBinders pat'  simonpj@microsoft.com committed Oct 03, 2006 376 377  ; (grhss', fvs) <- rnGRHSs PatBindRhs grhss -- No scoped type variables for pattern bindings  simonpj committed Jul 19, 2005 378   simonpj@microsoft.com committed Jan 25, 2006 379 380 381  ; 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 382   simonpj@microsoft.com committed Jan 25, 2006 383 rnBind sig_fn trim (L loc (FunBind { fun_id = name, fun_infix = inf, fun_matches = matches }))  simonpj committed Aug 10, 2005 384 385 386  = setSrcSpan loc $do { new_name <- lookupLocatedBndrRn name ; let plain_name = unLoc new_name  simonpj committed Jul 19, 2005 387 388  ; (matches', fvs) <- bindSigTyVarsFV (sig_fn plain_name)$  simonpj@microsoft.com committed Oct 03, 2006 389  -- bindSigTyVars tests for Opt_ScopedTyVars  simonpj@microsoft.com committed Aug 22, 2007 390  rnMatchGroup (FunRhs plain_name inf) matches  simonpj committed Jul 19, 2005 391 392 393  ; checkPrecMatch inf plain_name matches'  simonpj@microsoft.com committed Jan 25, 2006 394  ; return (L loc (FunBind { fun_id = new_name, fun_infix = inf, fun_matches = matches',  andy@galois.com committed Oct 24, 2006 395  bind_fvs = trim fvs, fun_co_fn = idHsWrapper, fun_tick = Nothing }),  simonpj@microsoft.com committed Jan 25, 2006 396  [plain_name], fvs)  simonpj committed Jul 19, 2005 397  }  simonmar committed Jun 17, 1999 398 399 400 401 \end{code} @rnMethodBinds@ is used for the method bindings of a class and an instance  simonmar committed Dec 10, 2003 402 declaration. Like @rnBinds@ but without dependency analysis.  simonmar committed Jun 17, 1999 403 404 405 406 407 408 409 410 411 412 413 414 415 416  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 417 rnMethodBinds :: Name -- Class name  simonpj@microsoft.com committed Jun 12, 2006 418  -> (Name -> [Name]) -- Signature tyvar function  simonpj committed Dec 06, 2001 419  -> [Name] -- Names for generic type variables  simonpj committed Sep 30, 2004 420  -> LHsBinds RdrName  simonmar committed Dec 10, 2003 421  -> RnM (LHsBinds Name, FreeVars)  simonmar committed Jun 17, 1999 422   simonpj@microsoft.com committed Jun 12, 2006 423 rnMethodBinds cls sig_fn gen_tyvars binds  simonmar committed Dec 10, 2003 424 425  = foldM do_one (emptyBag,emptyFVs) (bagToList binds) where do_one (binds,fvs) bind = do  simonpj@microsoft.com committed Jun 12, 2006 426  (bind', fvs_bind) <- rnMethodBind cls sig_fn gen_tyvars bind  simonmar committed Dec 10, 2003 427  return (bind' unionBags binds, fvs_bind plusFV fvs)  simonmar committed Jun 17, 1999 428   simonpj@microsoft.com committed Jun 12, 2006 429 430 431 rnMethodBind cls sig_fn gen_tyvars (L loc (FunBind { fun_id = name, fun_infix = inf, fun_matches = MatchGroup matches _ })) = setSrcSpan loc $ David Himmelstrup committed Jun 21, 2007 432  lookupInstDeclBndr cls name thenM \ sel_name ->  simonpj@microsoft.com committed Jun 12, 2006 433  let plain_name = unLoc sel_name in  simonmar committed Jun 17, 1999 434 435  -- We use the selector name as the binder  simonpj@microsoft.com committed Jun 12, 2006 436  bindSigTyVarsFV (sig_fn plain_name)$  simonmar committed Dec 10, 2003 437  mapFvRn (rn_match plain_name) matches thenM \ (new_matches, fvs) ->  simonpj committed Sep 30, 2004 438 439 440 441  let new_group = MatchGroup new_matches placeHolderType in checkPrecMatch inf plain_name new_group thenM_  chak@cse.unsw.edu.au. committed Dec 19, 2006 442 443 444 445 446  returnM (unitBag (L loc (FunBind { fun_id = sel_name, fun_infix = inf, fun_matches = new_group, bind_fvs = fvs, fun_co_fn = idHsWrapper, fun_tick = Nothing })),  simonpj@microsoft.com committed Jan 25, 2006 447  fvs addOneFV plain_name)  simonpj committed Jul 19, 2005 448  -- The 'fvs' field isn't used for method binds  simonpj committed Oct 03, 2000 449  where  simonpj committed Sep 30, 2004 450 451  -- Truly gruesome; bring into scope the correct members of the generic -- type variables. See comments in RnSource.rnSourceDecl(ClassDecl)  simonmar committed Dec 10, 2003 452  rn_match sel_name match@(L _ (Match (L _ (TypePat ty) : _) _ _))  simonpj committed Sep 27, 2002 453  = extendTyVarEnvFVRn gen_tvs $ simonpj@microsoft.com committed Aug 22, 2007 454  rnMatch (FunRhs sel_name inf) match  simonpj committed Oct 03, 2000 455  where  simonmar committed Dec 10, 2003 456  tvs = map (rdrNameOcc.unLoc) (extractHsTyRdrTyVars ty)  simonpj committed Oct 03, 2000 457 458  gen_tvs = [tv | tv <- gen_tyvars, nameOccName tv elem tvs]  simonpj@microsoft.com committed Aug 22, 2007 459  rn_match sel_name match = rnMatch (FunRhs sel_name inf) match  simonmar committed Dec 10, 2003 460   simonmar committed Jun 17, 1999 461 462  -- Can't handle method pattern-bindings which bind multiple methods.  simonpj@microsoft.com committed Jun 12, 2006 463 rnMethodBind cls sig_fn gen_tyvars mbind@(L loc (PatBind other_pat _ _ _))  simonmar committed Dec 10, 2003 464 465  = addLocErr mbind methodBindErr thenM_ returnM (emptyBag, emptyFVs)  simonmar committed Jun 17, 1999 466 467 468 \end{code}  chak@cse.unsw.edu.au. committed Sep 15, 2006 469   simonmar committed Jun 17, 1999 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 %************************************************************************ %* * \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 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 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 504 505  -- Check for (a) duplicate signatures -- (b) signatures for things not in this group  simonpj committed Aug 12, 2005 506 507  = do { mappM_ unknownSigErr (filter (not . ok_sig) sigs') ; mappM_ dupSigDeclErr (findDupsEq eqHsSig sigs') }  simonpj committed Sep 27, 2002 508  where  simonpj committed Jul 25, 2005 509  -- Don't complain about an unbound name again  simonpj committed Aug 12, 2005 510 511 512 513  sigs' = filterOut bad_name sigs bad_name sig = case sigName sig of Just n -> isUnboundName n other -> False  simonpj committed Jul 25, 2005 514   simonpj committed Jul 19, 2005 515 -- We use lookupLocatedSigOccRn in the signatures, which is a little bit unsatisfactory  simonmar committed Jun 17, 1999 516 517 518 519 520 521 522 523 -- 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 524 renameSig :: Sig RdrName -> RnM (Sig Name)  simonpj committed Oct 09, 2003 525 -- FixitSig is renamed elsewhere.  simonpj committed Oct 27, 2005 526 renameSig (TypeSig v ty)  simonmar committed Dec 10, 2003 527  = lookupLocatedSigOccRn v thenM \ new_v ->  simonpj committed Sep 13, 2002 528  rnHsSigType (quotes (ppr v)) ty thenM \ new_ty ->  simonpj committed Oct 27, 2005 529  returnM (TypeSig new_v new_ty)  simonmar committed Jun 17, 1999 530   simonmar committed Dec 10, 2003 531 532 533 renameSig (SpecInstSig ty) = rnLHsType (text "A SPECIALISE instance pragma") ty thenM \ new_ty -> returnM (SpecInstSig new_ty)  simonmar committed Jun 17, 1999 534   simonpj committed Oct 27, 2005 535 renameSig (SpecSig v ty inl)  simonmar committed Dec 10, 2003 536  = lookupLocatedSigOccRn v thenM \ new_v ->  simonpj committed Sep 13, 2002 537  rnHsSigType (quotes (ppr v)) ty thenM \ new_ty ->  simonpj committed Oct 27, 2005 538  returnM (SpecSig new_v new_ty inl)  simonmar committed Jun 17, 1999 539   simonpj committed Oct 27, 2005 540 renameSig (InlineSig v s)  simonmar committed Dec 10, 2003 541  = lookupLocatedSigOccRn v thenM \ new_v ->  simonpj committed Oct 27, 2005 542  returnM (InlineSig new_v s)  simonmar committed Jun 17, 1999 543 544 545 \end{code}  simonpj committed Jul 19, 2005 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 ************************************************************************ * * \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$  Ian Lynagh committed Jul 09, 2007 565  doptM Opt_PatternSignatures thenM \ opt_PatternSignatures ->  simonpj committed Jul 19, 2005 566 567  (case maybe_rhs_sig of Nothing -> returnM (Nothing, emptyFVs)  Ian Lynagh committed Jul 09, 2007 568  Just ty | opt_PatternSignatures -> rnHsTypeFVs doc_sig ty thenM \ (ty', ty_fvs) ->  simonpj committed Jul 19, 2005 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  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)  Ian Lynagh committed Jul 08, 2007 606  = do { pattern_guards_allowed <- doptM Opt_PatternGuards  simonpj committed Jul 19, 2005 607 608  ; ((guards', rhs'), fvs) <- rnStmts (PatGuard ctxt) guards $rnLExpr rhs  simonpj@microsoft.com committed Feb 06, 2006 609   Ian Lynagh committed Jul 08, 2007 610  ; checkM (pattern_guards_allowed || is_standard_guard guards')  simonpj@microsoft.com committed Feb 06, 2006 611 612  (addWarn (nonStdGuardErr guards'))  simonpj committed Jul 19, 2005 613 614 615 616 617 618 619 620 621 622  ; return (GRHS guards' rhs', fvs) } where -- Standard Haskell 1.4 guards are just a single boolean -- expression, rather than a list of qualifiers as in the -- Glasgow extension is_standard_guard [] = True is_standard_guard [L _ (ExprStmt _ _ _)] = True is_standard_guard other = False \end{code}  simonmar committed Jun 17, 1999 623 624 625 626 627 628 629 %************************************************************************ %* * \subsection{Error messages} %* * %************************************************************************ \begin{code}  simonpj committed Jul 19, 2005 630 dupSigDeclErr sigs@(L loc sig : _)  simonmar committed Dec 10, 2003 631 632  = addErrAt loc$ vcat [ptext SLIT("Duplicate") <+> what_it_is <> colon,  simonpj committed Jul 19, 2005 633  nest 2 (vcat (map ppr_sig sigs))]  simonmar committed Jun 17, 1999 634  where  simonmar committed Dec 10, 2003 635 636  what_it_is = hsSigDoc sig ppr_sig (L loc sig) = ppr loc <> colon <+> ppr sig  simonmar committed Jun 17, 1999 637   simonmar committed Dec 10, 2003 638 unknownSigErr (L loc sig)  simonpj@microsoft.com committed May 02, 2007 639 640 641 642  = do { mod <- getModule ; addErrAt loc \$ vcat [sep [ptext SLIT("Misplaced") <+> what_it_is <> colon, ppr sig], extra_stuff mod sig] }  simonmar committed Jun 17, 1999 643  where  simonmar committed Dec 10, 2003 644  what_it_is = hsSigDoc sig  simonpj@microsoft.com committed May 02, 2007 645 646 647 648 649 650 651 652  extra_stuff mod (TypeSig (L _ n) _) | nameIsLocalOrFrom mod n = ptext SLIT("The type signature must be given where") <+> quotes (ppr n) <+> ptext SLIT("is declared") | otherwise = ptext SLIT("You cannot give a type signature for an imported value") extra_stuff mod other = empty  simonmar committed Jun 17, 1999 653 654  methodBindErr mbind  simonpj committed Oct 11, 2004 655  = hang (ptext SLIT("Pattern bindings (except simple variables) not allowed in instance declarations"))  simonpj committed Jan 27, 2005 656 657 658 659 660  2 (ppr mbind) bindsInHsBootFile mbinds = hang (ptext SLIT("Bindings in hs-boot files are not allowed")) 2 (ppr mbinds)  simonpj committed Jul 19, 2005 661   simonpj@microsoft.com committed Feb 06, 2006 662 nonStdGuardErr guards  Ian Lynagh committed Jul 08, 2007 663  = hang (ptext SLIT("accepting non-standard pattern guards (use -XPatternGuards to suppress this message)"))  simonpj@microsoft.com committed Feb 06, 2006 664  4 (interpp'SP guards)  simonmar committed Jun 17, 1999 665 \end{code}