-%
-% (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 (
- rnTopBinds, rnTopMonoBinds,
- rnMethodBinds, renameSigs,
- rnBinds,
- unknownSigErr
- ) where
-
-#include "HsVersions.h"
-
-import {-# SOURCE #-} RnSource ( rnHsSigType )
-
-import HsSyn
-import HsBinds ( sigsForMe )
-import RdrHsSyn
-import RnHsSyn
-import RnMonad
-import RnExpr ( rnMatch, rnGRHSs, rnPat, checkPrecMatch )
-import RnEnv ( bindLocatedLocalsRn, lookupBndrRn, lookupGlobalOccRn,
- warnUnusedLocalBinds, mapFvRn,
- FreeVars, emptyFVs, plusFV, plusFVs, unitFV, addOneFV,
- unknownNameErr
- )
-import CmdLineOpts ( opt_WarnMissingSigs )
-import Digraph ( stronglyConnComp, SCC(..) )
-import Name ( OccName, Name, nameOccName )
-import NameSet
-import RdrName ( RdrName, rdrNameOcc )
-import BasicTypes ( RecFlag(..), TopLevelFlag(..) )
-import Util ( thenCmp, removeDups )
-import List ( partition )
-import ListSetOps ( minusList )
-import Bag ( bagToList )
-import FiniteMap ( lookupFM, listToFM )
-import Maybe ( isJust )
-import Outputable
-\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).
-
-\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
-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}
-
-%************************************************************************
-%* *
-%* analysing polymorphic bindings (HsBinds, Bind, MonoBinds) *
-%* *
-%************************************************************************
-
-\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
-(a @FlatMonoBindsInfo@) containing:
-
-\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).
-
-%************************************************************************
-%* *
-%* Top-level bindings
-%* *
-%************************************************************************
-
-@rnTopBinds@ assumes that the environment already
-contains bindings for the binders of this particular binding.
-
-\begin{code}
-rnTopBinds :: RdrNameHsBinds -> RnMS (RenamedHsBinds, FreeVars)
-
-rnTopBinds EmptyBinds = returnRn (EmptyBinds, emptyFVs)
-rnTopBinds (MonoBind bind sigs _) = rnTopMonoBinds bind sigs
- -- The parser doesn't produce other forms
-
-
-rnTopMonoBinds EmptyMonoBinds sigs
- = returnRn (EmptyBinds, emptyFVs)
-
-rnTopMonoBinds mbinds sigs
- = mapRn lookupBndrRn binder_rdr_names `thenRn` \ binder_names ->
- let
- binder_set = mkNameSet binder_names
- binder_occ_fm = listToFM [(nameOccName x,x) | x <- binder_names]
- in
- renameSigs opt_WarnMissingSigs binder_set
- (lookupSigOccRn binder_occ_fm) sigs `thenRn` \ (siglist, sig_fvs) ->
- rn_mono_binds siglist mbinds `thenRn` \ (final_binds, bind_fvs) ->
- returnRn (final_binds, bind_fvs `plusFV` sig_fvs)
- where
- binder_rdr_names = map fst (bagToList (collectMonoBinders mbinds))
-
--- the names appearing in the sigs have to be bound by
--- this group's binders.
-lookupSigOccRn binder_occ_fm rdr_name
- = case lookupFM binder_occ_fm (rdrNameOcc rdr_name) of
- Nothing -> failWithRn (mkUnboundName rdr_name)
- (unknownNameErr rdr_name)
- Just x -> returnRn x
-\end{code}
-
-%************************************************************************
-%* *
-%* Nested binds
-%* *
-%************************************************************************
-
-@rnMonoBinds@
- - collects up the binders for this declaration group,
- - checks that they form a set
- - extends the environment to bind them to new local names
- - calls @rnMonoBinds@ to do the real work
-
-\begin{code}
-rnBinds :: RdrNameHsBinds
- -> (RenamedHsBinds -> RnMS (result, FreeVars))
- -> RnMS (result, FreeVars)
-
-rnBinds EmptyBinds thing_inside = thing_inside EmptyBinds
-rnBinds (MonoBind bind sigs _) thing_inside = rnMonoBinds bind sigs thing_inside
- -- the parser doesn't produce other forms
-
-
-rnMonoBinds :: RdrNameMonoBinds
- -> [RdrNameSig]
- -> (RenamedHsBinds -> RnMS (result, FreeVars))
- -> RnMS (result, FreeVars)
-
-rnMonoBinds EmptyMonoBinds sigs thing_inside = thing_inside EmptyBinds
-
-rnMonoBinds mbinds sigs thing_inside -- 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
- bindLocatedLocalsRn (text "a binding group") mbinders_w_srclocs $ \ new_mbinders ->
- let
- binder_set = mkNameSet new_mbinders
-
- -- Weed out the fixity declarations that do not
- -- apply to any of the binders in this group.
- (sigs_for_me, fixes_not_for_me) = partition forLocalBind sigs
-
- forLocalBind (FixSig sig@(FixitySig name _ _ )) =
- isJust (lookupFM binder_occ_fm (rdrNameOcc name))
- forLocalBind _ = True
-
- binder_occ_fm = listToFM [(nameOccName x,x) | x <- new_mbinders]
-
- in
- -- Report the fixity declarations in this group that
- -- don't refer to any of the group's binders.
- --
- mapRn_ (unknownSigErr) fixes_not_for_me `thenRn_`
- renameSigs False binder_set
- (lookupSigOccRn binder_occ_fm) sigs_for_me `thenRn` \ (siglist, sig_fvs) ->
- let
- fixity_sigs = [(name,sig) | FixSig sig@(FixitySig name _ _) <- siglist ]
- in
- -- Install the fixity declarations that do apply here and go.
- extendFixityEnv fixity_sigs (
- rn_mono_binds siglist mbinds
- ) `thenRn` \ (binds, bind_fvs) ->
-
- -- Now do the "thing inside", and deal with the free-variable calculations
- thing_inside binds `thenRn` \ (result,result_fvs) ->
- let
- all_fvs = result_fvs `plusFV` bind_fvs `plusFV` sig_fvs
- unused_binders = nameSetToList (binder_set `minusNameSet` all_fvs)
- in
- warnUnusedLocalBinds unused_binders `thenRn_`
- returnRn (result, delListFromNameSet all_fvs new_mbinders)
- where
- mbinders_w_srclocs = bagToList (collectMonoBinders mbinds)
-\end{code}
-
-
-%************************************************************************
-%* *
-%* MonoBinds -- the main work is done here
-%* *
-%************************************************************************
-
-@rn_mono_binds@ 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
-@rnMonoBinds@ (for the nested ones).
-
-\begin{code}
-rn_mono_binds :: [RenamedSig] -- Signatures attached to this group
- -> RdrNameMonoBinds
- -> RnMS (RenamedHsBinds, --
- FreeVars) -- Free variables
-
-rn_mono_binds siglist mbinds
- =
- -- 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 siglist mbinds `thenRn` \ mbinds_info ->
-
- -- Do the SCC analysis
- let
- edges = mkEdges (mbinds_info `zip` [(0::Int)..])
- scc_result = stronglyConnComp edges
- final_binds = foldr1 ThenBinds (map reconstructCycle scc_result)
-
- -- Deal with bound and free-var calculation
- rhs_fvs = plusFVs [fvs | (_,fvs,_,_) <- mbinds_info]
- in
- returnRn (final_binds, rhs_fvs)
-\end{code}
-
-@flattenMonoBinds@ is ever-so-slightly magical in that it sticks
-unique ``vertex tags'' on its output; minor plumbing required.
-
-Sigh - need to pass along the signatures for the group of bindings,
-in case any of them
-
-\begin{code}
-flattenMonoBinds :: [RenamedSig] -- Signatures
- -> RdrNameMonoBinds
- -> RnMS [FlatMonoBindsInfo]
-
-flattenMonoBinds sigs EmptyMonoBinds = returnRn []
-
-flattenMonoBinds sigs (AndMonoBinds bs1 bs2)
- = flattenMonoBinds sigs bs1 `thenRn` \ flat1 ->
- flattenMonoBinds sigs bs2 `thenRn` \ flat2 ->
- returnRn (flat1 ++ flat2)
-
-flattenMonoBinds sigs (PatMonoBind pat grhss locn)
- = pushSrcLocRn locn $
- rnPat pat `thenRn` \ (pat', pat_fvs) ->
-
- -- Find which things are bound in this group
- let
- names_bound_here = mkNameSet (collectPatBinders pat')
- sigs_for_me = sigsForMe (`elemNameSet` names_bound_here) sigs
- in
- rnGRHSs grhss `thenRn` \ (grhss', fvs) ->
- returnRn
- [(names_bound_here,
- fvs `plusFV` pat_fvs,
- PatMonoBind pat' grhss' locn,
- sigs_for_me
- )]
-
-flattenMonoBinds sigs (FunMonoBind name inf matches locn)
- = pushSrcLocRn locn $
- lookupBndrRn name `thenRn` \ new_name ->
- let
- sigs_for_me = sigsForMe (new_name ==) sigs
- in
- mapFvRn rnMatch matches `thenRn` \ (new_matches, fvs) ->
- mapRn_ (checkPrecMatch inf new_name) new_matches `thenRn_`
- returnRn
- [(unitNameSet new_name,
- fvs,
- FunMonoBind new_name inf new_matches locn,
- sigs_for_me
- )]
-\end{code}
-
-
-@rnMethodBinds@ is used for the method bindings of a class and an instance
-declaration. like @rnMonoBinds@ but without dependency analysis.
-
-\begin{code}
-rnMethodBinds :: RdrNameMonoBinds -> RnMS (RenamedMonoBinds, FreeVars)
-
-rnMethodBinds EmptyMonoBinds = returnRn (EmptyMonoBinds, emptyFVs)
-
-rnMethodBinds (AndMonoBinds mb1 mb2)
- = rnMethodBinds mb1 `thenRn` \ (mb1', fvs1) ->
- rnMethodBinds mb2 `thenRn` \ (mb2', fvs2) ->
- returnRn (mb1' `AndMonoBinds` mb2', fvs1 `plusFV` fvs2)
-
-rnMethodBinds (FunMonoBind name inf matches locn)
- = pushSrcLocRn locn $
-
- lookupGlobalOccRn name `thenRn` \ sel_name ->
- -- We use the selector name as the binder
-
- mapFvRn rnMatch matches `thenRn` \ (new_matches, fvs) ->
- mapRn_ (checkPrecMatch inf sel_name) new_matches `thenRn_`
- returnRn (FunMonoBind sel_name inf new_matches locn, fvs)
-
-rnMethodBinds (PatMonoBind (VarPatIn name) grhss locn)
- = pushSrcLocRn locn $
- lookupGlobalOccRn name `thenRn` \ sel_name ->
- rnGRHSs grhss `thenRn` \ (grhss', fvs) ->
- returnRn (PatMonoBind (VarPatIn sel_name) grhss' locn, fvs)
-
--- Can't handle method pattern-bindings which bind multiple methods.
-rnMethodBinds mbind@(PatMonoBind other_pat _ locn)
- = pushSrcLocRn locn $
- failWithRn (EmptyMonoBinds, emptyFVs) (methodBindErr mbind)
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection[reconstruct-deps]{Reconstructing dependencies}
-%* *
-%************************************************************************
-
-This @MonoBinds@- and @ClassDecls@-specific code is segregated here,
-as the two cases are similar.
-
-\begin{code}
-reconstructCycle :: SCC FlatMonoBindsInfo
- -> RenamedHsBinds
-
-reconstructCycle (AcyclicSCC (_, _, binds, sigs))
- = MonoBind binds sigs NonRecursive
-
-reconstructCycle (CyclicSCC cycle)
- = MonoBind this_gp_binds this_gp_sigs Recursive
- where
- this_gp_binds = foldr1 AndMonoBinds [binds | (_, _, binds, _) <- cycle]
- this_gp_sigs = foldr1 (++) [sigs | (_, _, _, sigs) <- cycle]
-\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.
-
-\begin{code}
-type FlatMonoBindsInfo
- = (NameSet, -- Set of names defined in this vertex
- NameSet, -- Set of names used in this vertex
- RenamedMonoBinds,
- [RenamedSig]) -- Signatures, if any, for this vertex
-
-mkEdges :: [(FlatMonoBindsInfo, VertexTag)] -> [(FlatMonoBindsInfo, VertexTag, [VertexTag])]
-
-mkEdges flat_info
- = [ (info, tag, dest_vertices (nameSetToList names_used))
- | (info@(names_defined, names_used, mbind, sigs), tag) <- flat_info
- ]
- where
- -- An edge (v,v') indicates that v depends on v'
- dest_vertices src_mentions = [ target_vertex
- | ((names_defined, _, _, _), target_vertex) <- flat_info,
- mentioned_name <- src_mentions,
- mentioned_name `elemNameSet` names_defined
- ]
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsubsection[dep-Sigs]{Signatures (and user-pragmas for values)}
-%* *
-%************************************************************************
-
-@renameSigs@ 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.
-
-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}
-renameSigs :: Bool -- True => warn if (required) type signatures are missing.
- -> NameSet -- Set of names bound in this group
- -> (RdrName -> RnMS Name)
- -> [RdrNameSig]
- -> RnMS ([RenamedSig], FreeVars) -- List of Sig constructors
-
-renameSigs sigs_required binders lookup_occ_nm sigs
- = -- Rename the signatures
- mapFvRn (renameSig lookup_occ_nm) sigs `thenRn` \ (sigs', fvs) ->
-
- -- Check for (a) duplicate signatures
- -- (b) signatures for things not in this group
- -- (c) optionally, bindings with no signature
- let
- (goodies, dups) = removeDups cmp_sig (sigsForMe (not . isUnboundName) sigs')
- not_this_group = sigsForMe (not . (`elemNameSet` binders)) goodies
- type_sig_vars = [n | Sig n _ _ <- goodies]
- un_sigd_binders | sigs_required = nameSetToList binders `minusList` type_sig_vars
- | otherwise = []
- in
- mapRn_ dupSigDeclErr dups `thenRn_`
- mapRn_ unknownSigErr not_this_group `thenRn_`
- mapRn_ (addWarnRn.missingSigWarn) un_sigd_binders `thenRn_`
- returnRn (sigs', fvs)
- -- bad ones and all:
- -- we need bindings of *some* sort for every name
-
--- We use lookupOccRn 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 lookup_occ_nm (Sig v ty src_loc)
- = pushSrcLocRn src_loc $
- lookup_occ_nm v `thenRn` \ new_v ->
- rnHsSigType (quotes (ppr v)) ty `thenRn` \ (new_ty,fvs) ->
- returnRn (Sig new_v new_ty src_loc, fvs `addOneFV` new_v)
-
-renameSig _ (SpecInstSig ty src_loc)
- = pushSrcLocRn src_loc $
- rnHsSigType (text "A SPECIALISE instance pragma") ty `thenRn` \ (new_ty, fvs) ->
- returnRn (SpecInstSig new_ty src_loc, fvs)
-
-renameSig lookup_occ_nm (SpecSig v ty src_loc)
- = pushSrcLocRn src_loc $
- lookup_occ_nm v `thenRn` \ new_v ->
- rnHsSigType (quotes (ppr v)) ty `thenRn` \ (new_ty,fvs) ->
- returnRn (SpecSig new_v new_ty src_loc, fvs `addOneFV` new_v)
-
-renameSig lookup_occ_nm (InlineSig v src_loc)
- = pushSrcLocRn src_loc $
- lookup_occ_nm v `thenRn` \ new_v ->
- returnRn (InlineSig new_v src_loc, unitFV new_v)
-
-renameSig lookup_occ_nm (FixSig (FixitySig v fix src_loc))
- = pushSrcLocRn src_loc $
- lookup_occ_nm v `thenRn` \ new_v ->
- returnRn (FixSig (FixitySig new_v fix src_loc), unitFV new_v)
-
-renameSig lookup_occ_nm (NoInlineSig v src_loc)
- = pushSrcLocRn src_loc $
- lookup_occ_nm v `thenRn` \ new_v ->
- returnRn (NoInlineSig new_v src_loc, unitFV new_v)
-\end{code}
-
-Checking for distinct signatures; oh, so boring
-
-\begin{code}
-cmp_sig :: RenamedSig -> RenamedSig -> Ordering
-cmp_sig (Sig n1 _ _) (Sig n2 _ _) = n1 `compare` n2
-cmp_sig (InlineSig n1 _) (InlineSig n2 _) = n1 `compare` n2
-cmp_sig (NoInlineSig n1 _) (NoInlineSig n2 _) = n1 `compare` n2
-cmp_sig (SpecInstSig ty1 _) (SpecInstSig ty2 _) = cmpHsType compare ty1 ty2
-cmp_sig (SpecSig n1 ty1 _) (SpecSig n2 ty2 _)
- = -- may have many specialisations for one value;
- -- but not ones that are exactly the same...
- thenCmp (n1 `compare` n2) (cmpHsType compare ty1 ty2)
-
-cmp_sig other_1 other_2 -- Tags *must* be different
- | (sig_tag other_1) _LT_ (sig_tag other_2) = LT
- | otherwise = GT
-
-sig_tag (Sig n1 _ _) = (ILIT(1) :: FAST_INT)
-sig_tag (SpecSig n1 _ _) = ILIT(2)
-sig_tag (InlineSig n1 _) = ILIT(3)
-sig_tag (NoInlineSig n1 _) = ILIT(4)
-sig_tag (SpecInstSig _ _) = ILIT(5)
-sig_tag (FixSig _) = ILIT(6)
-sig_tag _ = panic# "tag(RnBinds)"
-\end{code}
-
-%************************************************************************
-%* *
-\subsection{Error messages}
-%* *
-%************************************************************************
-
-\begin{code}
-dupSigDeclErr (sig:sigs)
- = pushSrcLocRn loc $
- addErrRn (sep [ptext SLIT("Duplicate") <+> ptext what_it_is <> colon,
- ppr sig])
- where
- (what_it_is, loc) = sig_doc sig
-
-unknownSigErr sig
- = pushSrcLocRn loc $
- addErrRn (sep [ptext SLIT("Misplaced"),
- ptext what_it_is <> colon,
- ppr sig])
- where
- (what_it_is, loc) = sig_doc sig
-
-sig_doc (Sig _ _ loc) = (SLIT("type signature"),loc)
-sig_doc (ClassOpSig _ _ _ loc) = (SLIT("class-method type signature"), loc)
-sig_doc (SpecSig _ _ loc) = (SLIT("SPECIALISE pragma"),loc)
-sig_doc (InlineSig _ loc) = (SLIT("INLINE pragma"),loc)
-sig_doc (NoInlineSig _ loc) = (SLIT("NOINLINE pragma"),loc)
-sig_doc (SpecInstSig _ loc) = (SLIT("SPECIALISE instance pragma"),loc)
-sig_doc (FixSig (FixitySig _ _ loc)) = (SLIT("fixity declaration"), loc)
-
-missingSigWarn var
- = sep [ptext SLIT("definition but no type signature for"), quotes (ppr var)]
-
-methodBindErr mbind
- = hang (ptext SLIT("Can't handle multiple methods defined by one pattern binding"))
- 4 (ppr mbind)
-\end{code}
+%\r
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998\r
+%\r
+\section[RnBinds]{Renaming and dependency analysis of bindings}\r
+\r
+This module does renaming and dependency analysis on value bindings in\r
+the abstract syntax. It does {\em not} do cycle-checks on class or\r
+type-synonym declarations; those cannot be done at this stage because\r
+they may be affected by renaming (which isn't fully worked out yet).\r
+\r
+\begin{code}\r
+module RnBinds (\r
+ rnTopBinds, rnTopMonoBinds,\r
+ rnMethodBinds, renameSigs,\r
+ rnBinds,\r
+ unknownSigErr\r
+ ) where\r
+\r
+#include "HsVersions.h"\r
+\r
+import {-# SOURCE #-} RnSource ( rnHsSigType )\r
+\r
+import HsSyn\r
+import HsBinds ( sigsForMe )\r
+import RdrHsSyn\r
+import RnHsSyn\r
+import RnMonad\r
+import RnExpr ( rnMatch, rnGRHSs, rnPat, checkPrecMatch )\r
+import RnEnv ( bindLocatedLocalsRn, lookupBndrRn, lookupGlobalOccRn,\r
+ warnUnusedLocalBinds, mapFvRn, \r
+ FreeVars, emptyFVs, plusFV, plusFVs, unitFV, addOneFV,\r
+ unknownNameErr\r
+ )\r
+import CmdLineOpts ( opt_WarnMissingSigs )\r
+import Digraph ( stronglyConnComp, SCC(..) )\r
+import Name ( OccName, Name, nameOccName )\r
+import NameSet\r
+import RdrName ( RdrName, rdrNameOcc )\r
+import BasicTypes ( RecFlag(..), TopLevelFlag(..) )\r
+import Util ( thenCmp, removeDups )\r
+import List ( partition )\r
+import ListSetOps ( minusList )\r
+import Bag ( bagToList )\r
+import FiniteMap ( lookupFM, listToFM )\r
+import Maybe ( isJust )\r
+import Outputable\r
+\end{code}\r
+\r
+-- ToDo: Put the annotations into the monad, so that they arrive in the proper\r
+-- place and can be used when complaining.\r
+\r
+The code tree received by the function @rnBinds@ contains definitions\r
+in where-clauses which are all apparently mutually recursive, but which may\r
+not really depend upon each other. For example, in the top level program\r
+\begin{verbatim}\r
+f x = y where a = x\r
+ y = x\r
+\end{verbatim}\r
+the definitions of @a@ and @y@ do not depend on each other at all.\r
+Unfortunately, the typechecker cannot always check such definitions.\r
+\footnote{Mycroft, A. 1984. Polymorphic type schemes and recursive\r
+definitions. In Proceedings of the International Symposium on Programming,\r
+Toulouse, pp. 217-39. LNCS 167. Springer Verlag.}\r
+However, the typechecker usually can check definitions in which only the\r
+strongly connected components have been collected into recursive bindings.\r
+This is precisely what the function @rnBinds@ does.\r
+\r
+ToDo: deal with case where a single monobinds binds the same variable\r
+twice.\r
+\r
+The vertag tag is a unique @Int@; the tags only need to be unique\r
+within one @MonoBinds@, so that unique-Int plumbing is done explicitly\r
+(heavy monad machinery not needed).\r
+\r
+\begin{code}\r
+type VertexTag = Int\r
+type Cycle = [VertexTag]\r
+type Edge = (VertexTag, VertexTag)\r
+\end{code}\r
+\r
+%************************************************************************\r
+%* *\r
+%* naming conventions *\r
+%* *\r
+%************************************************************************\r
+\r
+\subsection[name-conventions]{Name conventions}\r
+\r
+The basic algorithm involves walking over the tree and returning a tuple\r
+containing the new tree plus its free variables. Some functions, such\r
+as those walking polymorphic bindings (HsBinds) and qualifier lists in\r
+list comprehensions (@Quals@), return the variables bound in local\r
+environments. These are then used to calculate the free variables of the\r
+expression evaluated in these environments.\r
+\r
+Conventions for variable names are as follows:\r
+\begin{itemize}\r
+\item\r
+new code is given a prime to distinguish it from the old.\r
+\r
+\item\r
+a set of variables defined in @Exp@ is written @dvExp@\r
+\r
+\item\r
+a set of variables free in @Exp@ is written @fvExp@\r
+\end{itemize}\r
+\r
+%************************************************************************\r
+%* *\r
+%* analysing polymorphic bindings (HsBinds, Bind, MonoBinds) *\r
+%* *\r
+%************************************************************************\r
+\r
+\subsubsection[dep-HsBinds]{Polymorphic bindings}\r
+\r
+Non-recursive expressions are reconstructed without any changes at top\r
+level, although their component expressions may have to be altered.\r
+However, non-recursive expressions are currently not expected as\r
+\Haskell{} programs, and this code should not be executed.\r
+\r
+Monomorphic bindings contain information that is returned in a tuple\r
+(a @FlatMonoBindsInfo@) containing:\r
+\r
+\begin{enumerate}\r
+\item\r
+a unique @Int@ that serves as the ``vertex tag'' for this binding.\r
+\r
+\item\r
+the name of a function or the names in a pattern. These are a set\r
+referred to as @dvLhs@, the defined variables of the left hand side.\r
+\r
+\item\r
+the free variables of the body. These are referred to as @fvBody@.\r
+\r
+\item\r
+the definition's actual code. This is referred to as just @code@.\r
+\end{enumerate}\r
+\r
+The function @nonRecDvFv@ returns two sets of variables. The first is\r
+the set of variables defined in the set of monomorphic bindings, while the\r
+second is the set of free variables in those bindings.\r
+\r
+The set of variables defined in a non-recursive binding is just the\r
+union of all of them, as @union@ removes duplicates. However, the\r
+free variables in each successive set of cumulative bindings is the\r
+union of those in the previous set plus those of the newest binding after\r
+the defined variables of the previous set have been removed.\r
+\r
+@rnMethodBinds@ deals only with the declarations in class and\r
+instance declarations. It expects only to see @FunMonoBind@s, and\r
+it expects the global environment to contain bindings for the binders\r
+(which are all class operations).\r
+\r
+%************************************************************************\r
+%* *\r
+%* Top-level bindings\r
+%* *\r
+%************************************************************************\r
+\r
+@rnTopBinds@ assumes that the environment already\r
+contains bindings for the binders of this particular binding.\r
+\r
+\begin{code}\r
+rnTopBinds :: RdrNameHsBinds -> RnMS (RenamedHsBinds, FreeVars)\r
+\r
+rnTopBinds EmptyBinds = returnRn (EmptyBinds, emptyFVs)\r
+rnTopBinds (MonoBind bind sigs _) = rnTopMonoBinds bind sigs\r
+ -- The parser doesn't produce other forms\r
+\r
+\r
+rnTopMonoBinds EmptyMonoBinds sigs \r
+ = returnRn (EmptyBinds, emptyFVs)\r
+\r
+rnTopMonoBinds mbinds sigs\r
+ = mapRn lookupBndrRn binder_rdr_names `thenRn` \ binder_names ->\r
+ let\r
+ binder_set = mkNameSet binder_names\r
+ binder_occ_fm = listToFM [(nameOccName x,x) | x <- binder_names]\r
+ in\r
+ renameSigs opt_WarnMissingSigs binder_set\r
+ (lookupSigOccRn binder_occ_fm) sigs `thenRn` \ (siglist, sig_fvs) ->\r
+ rn_mono_binds siglist mbinds `thenRn` \ (final_binds, bind_fvs) ->\r
+ returnRn (final_binds, bind_fvs `plusFV` sig_fvs)\r
+ where\r
+ binder_rdr_names = map fst (bagToList (collectMonoBinders mbinds))\r
+\r
+-- the names appearing in the sigs have to be bound by \r
+-- this group's binders.\r
+lookupSigOccRn binder_occ_fm rdr_name\r
+ = case lookupFM binder_occ_fm (rdrNameOcc rdr_name) of\r
+ Nothing -> failWithRn (mkUnboundName rdr_name)\r
+ (unknownNameErr rdr_name)\r
+ Just x -> returnRn x\r
+\end{code}\r
+\r
+%************************************************************************\r
+%* *\r
+%* Nested binds\r
+%* *\r
+%************************************************************************\r
+\r
+@rnMonoBinds@\r
+ - collects up the binders for this declaration group,\r
+ - checks that they form a set\r
+ - extends the environment to bind them to new local names\r
+ - calls @rnMonoBinds@ to do the real work\r
+\r
+\begin{code}\r
+rnBinds :: RdrNameHsBinds \r
+ -> (RenamedHsBinds -> RnMS (result, FreeVars))\r
+ -> RnMS (result, FreeVars)\r
+\r
+rnBinds EmptyBinds thing_inside = thing_inside EmptyBinds\r
+rnBinds (MonoBind bind sigs _) thing_inside = rnMonoBinds bind sigs thing_inside\r
+ -- the parser doesn't produce other forms\r
+\r
+\r
+rnMonoBinds :: RdrNameMonoBinds \r
+ -> [RdrNameSig]\r
+ -> (RenamedHsBinds -> RnMS (result, FreeVars))\r
+ -> RnMS (result, FreeVars)\r
+\r
+rnMonoBinds EmptyMonoBinds sigs thing_inside = thing_inside EmptyBinds\r
+\r
+rnMonoBinds mbinds sigs thing_inside -- Non-empty monobinds\r
+ = -- Extract all the binders in this group,\r
+ -- and extend current scope, inventing new names for the new binders\r
+ -- This also checks that the names form a set\r
+ bindLocatedLocalsRn (text "a binding group") mbinders_w_srclocs $ \ new_mbinders ->\r
+ let\r
+ binder_set = mkNameSet new_mbinders\r
+\r
+ -- Weed out the fixity declarations that do not\r
+ -- apply to any of the binders in this group.\r
+ (sigs_for_me, fixes_not_for_me) = partition forLocalBind sigs\r
+\r
+ forLocalBind (FixSig sig@(FixitySig name _ _ )) =\r
+ isJust (lookupFM binder_occ_fm (rdrNameOcc name))\r
+ forLocalBind _ = True\r
+\r
+ binder_occ_fm = listToFM [(nameOccName x,x) | x <- new_mbinders]\r
+\r
+ in\r
+ -- Report the fixity declarations in this group that \r
+ -- don't refer to any of the group's binders.\r
+ --\r
+ mapRn_ (unknownSigErr) fixes_not_for_me `thenRn_`\r
+ renameSigs False binder_set\r
+ (lookupSigOccRn binder_occ_fm) sigs_for_me `thenRn` \ (siglist, sig_fvs) ->\r
+ let\r
+ fixity_sigs = [(name,sig) | FixSig sig@(FixitySig name _ _) <- siglist ]\r
+ in\r
+ -- Install the fixity declarations that do apply here and go.\r
+ extendFixityEnv fixity_sigs (\r
+ rn_mono_binds siglist mbinds\r
+ ) `thenRn` \ (binds, bind_fvs) ->\r
+\r
+ -- Now do the "thing inside", and deal with the free-variable calculations\r
+ thing_inside binds `thenRn` \ (result,result_fvs) ->\r
+ let\r
+ all_fvs = result_fvs `plusFV` bind_fvs `plusFV` sig_fvs\r
+ unused_binders = nameSetToList (binder_set `minusNameSet` all_fvs)\r
+ in\r
+ warnUnusedLocalBinds unused_binders `thenRn_`\r
+ returnRn (result, delListFromNameSet all_fvs new_mbinders)\r
+ where\r
+ mbinders_w_srclocs = bagToList (collectMonoBinders mbinds)\r
+\end{code}\r
+\r
+\r
+%************************************************************************\r
+%* *\r
+%* MonoBinds -- the main work is done here\r
+%* *\r
+%************************************************************************\r
+\r
+@rn_mono_binds@ is used by *both* top-level and nested bindings. It\r
+assumes that all variables bound in this group are already in scope.\r
+This is done *either* by pass 3 (for the top-level bindings), *or* by\r
+@rnMonoBinds@ (for the nested ones).\r
+\r
+\begin{code}\r
+rn_mono_binds :: [RenamedSig] -- Signatures attached to this group\r
+ -> RdrNameMonoBinds \r
+ -> RnMS (RenamedHsBinds, -- \r
+ FreeVars) -- Free variables\r
+\r
+rn_mono_binds siglist mbinds\r
+ =\r
+ -- Rename the bindings, returning a MonoBindsInfo\r
+ -- which is a list of indivisible vertices so far as\r
+ -- the strongly-connected-components (SCC) analysis is concerned\r
+ flattenMonoBinds siglist mbinds `thenRn` \ mbinds_info ->\r
+\r
+ -- Do the SCC analysis\r
+ let \r
+ edges = mkEdges (mbinds_info `zip` [(0::Int)..])\r
+ scc_result = stronglyConnComp edges\r
+ final_binds = foldr1 ThenBinds (map reconstructCycle scc_result)\r
+\r
+ -- Deal with bound and free-var calculation\r
+ rhs_fvs = plusFVs [fvs | (_,fvs,_,_) <- mbinds_info]\r
+ in\r
+ returnRn (final_binds, rhs_fvs)\r
+\end{code}\r
+\r
+@flattenMonoBinds@ is ever-so-slightly magical in that it sticks\r
+unique ``vertex tags'' on its output; minor plumbing required.\r
+\r
+Sigh - need to pass along the signatures for the group of bindings,\r
+in case any of them \r
+\r
+\begin{code}\r
+flattenMonoBinds :: [RenamedSig] -- Signatures\r
+ -> RdrNameMonoBinds\r
+ -> RnMS [FlatMonoBindsInfo]\r
+\r
+flattenMonoBinds sigs EmptyMonoBinds = returnRn []\r
+\r
+flattenMonoBinds sigs (AndMonoBinds bs1 bs2)\r
+ = flattenMonoBinds sigs bs1 `thenRn` \ flat1 ->\r
+ flattenMonoBinds sigs bs2 `thenRn` \ flat2 ->\r
+ returnRn (flat1 ++ flat2)\r
+\r
+flattenMonoBinds sigs (PatMonoBind pat grhss locn)\r
+ = pushSrcLocRn locn $\r
+ rnPat pat `thenRn` \ (pat', pat_fvs) ->\r
+\r
+ -- Find which things are bound in this group\r
+ let\r
+ names_bound_here = mkNameSet (collectPatBinders pat')\r
+ sigs_for_me = sigsForMe (`elemNameSet` names_bound_here) sigs\r
+ in\r
+ rnGRHSs grhss `thenRn` \ (grhss', fvs) ->\r
+ returnRn \r
+ [(names_bound_here,\r
+ fvs `plusFV` pat_fvs,\r
+ PatMonoBind pat' grhss' locn,\r
+ sigs_for_me\r
+ )]\r
+\r
+flattenMonoBinds sigs (FunMonoBind name inf matches locn)\r
+ = pushSrcLocRn locn $\r
+ lookupBndrRn name `thenRn` \ new_name ->\r
+ let\r
+ sigs_for_me = sigsForMe (new_name ==) sigs\r
+ in\r
+ mapFvRn rnMatch matches `thenRn` \ (new_matches, fvs) ->\r
+ mapRn_ (checkPrecMatch inf new_name) new_matches `thenRn_`\r
+ returnRn\r
+ [(unitNameSet new_name,\r
+ fvs,\r
+ FunMonoBind new_name inf new_matches locn,\r
+ sigs_for_me\r
+ )]\r
+\end{code}\r
+\r
+\r
+@rnMethodBinds@ is used for the method bindings of a class and an instance\r
+declaration. like @rnMonoBinds@ but without dependency analysis.\r
+\r
+NOTA BENE: we record each *binder* of a method-bind group as a free variable.\r
+That's crucial when dealing with an instance decl:\r
+ instance Foo (T a) where\r
+ op x = ...\r
+This might be the *sole* occurrence of 'op' for an imported class Foo,\r
+and unless op occurs we won't treat the type signature of op in the class\r
+decl for Foo as a source of instance-decl gates. But we should! Indeed,\r
+in many ways the op in an instance decl is just like an occurrence, not\r
+a binder.\r
+\r
+\begin{code}\r
+rnMethodBinds :: RdrNameMonoBinds -> RnMS (RenamedMonoBinds, FreeVars)\r
+\r
+rnMethodBinds EmptyMonoBinds = returnRn (EmptyMonoBinds, emptyFVs)\r
+\r
+rnMethodBinds (AndMonoBinds mb1 mb2)\r
+ = rnMethodBinds mb1 `thenRn` \ (mb1', fvs1) ->\r
+ rnMethodBinds mb2 `thenRn` \ (mb2', fvs2) ->\r
+ returnRn (mb1' `AndMonoBinds` mb2', fvs1 `plusFV` fvs2)\r
+\r
+rnMethodBinds (FunMonoBind name inf matches locn)\r
+ = pushSrcLocRn locn $\r
+\r
+ lookupGlobalOccRn name `thenRn` \ sel_name -> \r
+ -- We use the selector name as the binder\r
+\r
+ mapFvRn rnMatch matches `thenRn` \ (new_matches, fvs) ->\r
+ mapRn_ (checkPrecMatch inf sel_name) new_matches `thenRn_`\r
+ returnRn (FunMonoBind sel_name inf new_matches locn, fvs `addOneFV` sel_name)\r
+\r
+rnMethodBinds (PatMonoBind (VarPatIn name) grhss locn)\r
+ = pushSrcLocRn locn $\r
+ lookupGlobalOccRn name `thenRn` \ sel_name -> \r
+ rnGRHSs grhss `thenRn` \ (grhss', fvs) ->\r
+ returnRn (PatMonoBind (VarPatIn sel_name) grhss' locn, fvs `addOneFV` sel_name)\r
+\r
+-- Can't handle method pattern-bindings which bind multiple methods.\r
+rnMethodBinds mbind@(PatMonoBind other_pat _ locn)\r
+ = pushSrcLocRn locn $\r
+ failWithRn (EmptyMonoBinds, emptyFVs) (methodBindErr mbind)\r
+\end{code}\r
+\r
+\r
+%************************************************************************\r
+%* *\r
+\subsection[reconstruct-deps]{Reconstructing dependencies}\r
+%* *\r
+%************************************************************************\r
+\r
+This @MonoBinds@- and @ClassDecls@-specific code is segregated here,\r
+as the two cases are similar.\r
+\r
+\begin{code}\r
+reconstructCycle :: SCC FlatMonoBindsInfo\r
+ -> RenamedHsBinds\r
+\r
+reconstructCycle (AcyclicSCC (_, _, binds, sigs))\r
+ = MonoBind binds sigs NonRecursive\r
+\r
+reconstructCycle (CyclicSCC cycle)\r
+ = MonoBind this_gp_binds this_gp_sigs Recursive\r
+ where\r
+ this_gp_binds = foldr1 AndMonoBinds [binds | (_, _, binds, _) <- cycle]\r
+ this_gp_sigs = foldr1 (++) [sigs | (_, _, _, sigs) <- cycle]\r
+\end{code}\r
+\r
+%************************************************************************\r
+%* *\r
+%* Manipulating FlatMonoBindInfo *\r
+%* *\r
+%************************************************************************\r
+\r
+During analysis a @MonoBinds@ is flattened to a @FlatMonoBindsInfo@.\r
+The @RenamedMonoBinds@ is always an empty bind, a pattern binding or\r
+a function binding, and has itself been dependency-analysed and\r
+renamed.\r
+\r
+\begin{code}\r
+type FlatMonoBindsInfo\r
+ = (NameSet, -- Set of names defined in this vertex\r
+ NameSet, -- Set of names used in this vertex\r
+ RenamedMonoBinds,\r
+ [RenamedSig]) -- Signatures, if any, for this vertex\r
+\r
+mkEdges :: [(FlatMonoBindsInfo, VertexTag)] -> [(FlatMonoBindsInfo, VertexTag, [VertexTag])]\r
+\r
+mkEdges flat_info\r
+ = [ (info, tag, dest_vertices (nameSetToList names_used))\r
+ | (info@(names_defined, names_used, mbind, sigs), tag) <- flat_info\r
+ ]\r
+ where\r
+ -- An edge (v,v') indicates that v depends on v'\r
+ dest_vertices src_mentions = [ target_vertex\r
+ | ((names_defined, _, _, _), target_vertex) <- flat_info,\r
+ mentioned_name <- src_mentions,\r
+ mentioned_name `elemNameSet` names_defined\r
+ ]\r
+\end{code}\r
+\r
+\r
+%************************************************************************\r
+%* *\r
+\subsubsection[dep-Sigs]{Signatures (and user-pragmas for values)}\r
+%* *\r
+%************************************************************************\r
+\r
+@renameSigs@ checks for: (a)~more than one sig for one thing;\r
+(b)~signatures given for things not bound here; (c)~with suitably\r
+flaggery, that all top-level things have type signatures.\r
+\r
+At the moment we don't gather free-var info from the types in\r
+signatures. We'd only need this if we wanted to report unused tyvars.\r
+\r
+\begin{code}\r
+renameSigs :: Bool -- True => warn if (required) type signatures are missing.\r
+ -> NameSet -- Set of names bound in this group\r
+ -> (RdrName -> RnMS Name)\r
+ -> [RdrNameSig]\r
+ -> RnMS ([RenamedSig], FreeVars) -- List of Sig constructors\r
+\r
+renameSigs sigs_required binders lookup_occ_nm sigs\r
+ = -- Rename the signatures\r
+ mapFvRn (renameSig lookup_occ_nm) sigs `thenRn` \ (sigs', fvs) ->\r
+\r
+ -- Check for (a) duplicate signatures\r
+ -- (b) signatures for things not in this group\r
+ -- (c) optionally, bindings with no signature\r
+ let\r
+ (goodies, dups) = removeDups cmp_sig (sigsForMe (not . isUnboundName) sigs')\r
+ not_this_group = sigsForMe (not . (`elemNameSet` binders)) goodies\r
+ type_sig_vars = [n | Sig n _ _ <- goodies]\r
+ un_sigd_binders | sigs_required = nameSetToList binders `minusList` type_sig_vars\r
+ | otherwise = []\r
+ in\r
+ mapRn_ dupSigDeclErr dups `thenRn_`\r
+ mapRn_ unknownSigErr not_this_group `thenRn_`\r
+ mapRn_ (addWarnRn.missingSigWarn) un_sigd_binders `thenRn_`\r
+ returnRn (sigs', fvs) \r
+ -- bad ones and all:\r
+ -- we need bindings of *some* sort for every name\r
+\r
+-- We use lookupOccRn in the signatures, which is a little bit unsatisfactory\r
+-- because this won't work for:\r
+-- instance Foo T where\r
+-- {-# INLINE op #-}\r
+-- Baz.op = ...\r
+-- We'll just rename the INLINE prag to refer to whatever other 'op'\r
+-- is in scope. (I'm assuming that Baz.op isn't in scope unqualified.)\r
+-- Doesn't seem worth much trouble to sort this.\r
+\r
+renameSig lookup_occ_nm (Sig v ty src_loc)\r
+ = pushSrcLocRn src_loc $\r
+ lookup_occ_nm v `thenRn` \ new_v ->\r
+ rnHsSigType (quotes (ppr v)) ty `thenRn` \ (new_ty,fvs) ->\r
+ returnRn (Sig new_v new_ty src_loc, fvs `addOneFV` new_v)\r
+\r
+renameSig _ (SpecInstSig ty src_loc)\r
+ = pushSrcLocRn src_loc $\r
+ rnHsSigType (text "A SPECIALISE instance pragma") ty `thenRn` \ (new_ty, fvs) ->\r
+ returnRn (SpecInstSig new_ty src_loc, fvs)\r
+\r
+renameSig lookup_occ_nm (SpecSig v ty src_loc)\r
+ = pushSrcLocRn src_loc $\r
+ lookup_occ_nm v `thenRn` \ new_v ->\r
+ rnHsSigType (quotes (ppr v)) ty `thenRn` \ (new_ty,fvs) ->\r
+ returnRn (SpecSig new_v new_ty src_loc, fvs `addOneFV` new_v)\r
+\r
+renameSig lookup_occ_nm (InlineSig v src_loc)\r
+ = pushSrcLocRn src_loc $\r
+ lookup_occ_nm v `thenRn` \ new_v ->\r
+ returnRn (InlineSig new_v src_loc, unitFV new_v)\r
+\r
+renameSig lookup_occ_nm (FixSig (FixitySig v fix src_loc))\r
+ = pushSrcLocRn src_loc $\r
+ lookup_occ_nm v `thenRn` \ new_v ->\r
+ returnRn (FixSig (FixitySig new_v fix src_loc), unitFV new_v)\r
+\r
+renameSig lookup_occ_nm (NoInlineSig v src_loc)\r
+ = pushSrcLocRn src_loc $\r
+ lookup_occ_nm v `thenRn` \ new_v ->\r
+ returnRn (NoInlineSig new_v src_loc, unitFV new_v)\r
+\end{code}\r
+\r
+Checking for distinct signatures; oh, so boring\r
+\r
+\begin{code}\r
+cmp_sig :: RenamedSig -> RenamedSig -> Ordering\r
+cmp_sig (Sig n1 _ _) (Sig n2 _ _) = n1 `compare` n2\r
+cmp_sig (InlineSig n1 _) (InlineSig n2 _) = n1 `compare` n2\r
+cmp_sig (NoInlineSig n1 _) (NoInlineSig n2 _) = n1 `compare` n2\r
+cmp_sig (SpecInstSig ty1 _) (SpecInstSig ty2 _) = cmpHsType compare ty1 ty2\r
+cmp_sig (SpecSig n1 ty1 _) (SpecSig n2 ty2 _) \r
+ = -- may have many specialisations for one value;\r
+ -- but not ones that are exactly the same...\r
+ thenCmp (n1 `compare` n2) (cmpHsType compare ty1 ty2)\r
+\r
+cmp_sig other_1 other_2 -- Tags *must* be different\r
+ | (sig_tag other_1) _LT_ (sig_tag other_2) = LT \r
+ | otherwise = GT\r
+\r
+sig_tag (Sig n1 _ _) = (ILIT(1) :: FAST_INT)\r
+sig_tag (SpecSig n1 _ _) = ILIT(2)\r
+sig_tag (InlineSig n1 _) = ILIT(3)\r
+sig_tag (NoInlineSig n1 _) = ILIT(4)\r
+sig_tag (SpecInstSig _ _) = ILIT(5)\r
+sig_tag (FixSig _) = ILIT(6)\r
+sig_tag _ = panic# "tag(RnBinds)"\r
+\end{code}\r
+\r
+%************************************************************************\r
+%* *\r
+\subsection{Error messages}\r
+%* *\r
+%************************************************************************\r
+\r
+\begin{code}\r
+dupSigDeclErr (sig:sigs)\r
+ = pushSrcLocRn loc $\r
+ addErrRn (sep [ptext SLIT("Duplicate") <+> ptext what_it_is <> colon,\r
+ ppr sig])\r
+ where\r
+ (what_it_is, loc) = sig_doc sig\r
+\r
+unknownSigErr sig\r
+ = pushSrcLocRn loc $\r
+ addErrRn (sep [ptext SLIT("Misplaced"),\r
+ ptext what_it_is <> colon,\r
+ ppr sig])\r
+ where\r
+ (what_it_is, loc) = sig_doc sig\r
+\r
+sig_doc (Sig _ _ loc) = (SLIT("type signature"),loc)\r
+sig_doc (ClassOpSig _ _ _ loc) = (SLIT("class-method type signature"), loc)\r
+sig_doc (SpecSig _ _ loc) = (SLIT("SPECIALISE pragma"),loc)\r
+sig_doc (InlineSig _ loc) = (SLIT("INLINE pragma"),loc)\r
+sig_doc (NoInlineSig _ loc) = (SLIT("NOINLINE pragma"),loc)\r
+sig_doc (SpecInstSig _ loc) = (SLIT("SPECIALISE instance pragma"),loc)\r
+sig_doc (FixSig (FixitySig _ _ loc)) = (SLIT("fixity declaration"), loc)\r
+\r
+missingSigWarn var\r
+ = sep [ptext SLIT("definition but no type signature for"), quotes (ppr var)]\r
+\r
+methodBindErr mbind\r
+ = hang (ptext SLIT("Can't handle multiple methods defined by one pattern binding"))\r
+ 4 (ppr mbind)\r
+\end{code}\r
projects / ghc-hetmet.git / blobdiff