module RnBinds (
rnTopBinds, rnTopMonoBinds,
rnMethodBinds, renameSigs,
- rnBinds, rnMonoBinds
+ rnBinds,
+ unknownSigErr
) where
#include "HsVersions.h"
import RnHsSyn
import RnMonad
import RnExpr ( rnMatch, rnGRHSs, rnPat, checkPrecMatch )
-import RnEnv ( bindLocatedLocalsRn, lookupBndrRn, lookupOccRn, lookupGlobalOccRn,
- isUnboundName, warnUnusedBinds,
- FreeVars, emptyFVs, plusFV, plusFVs, unitFV
+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 )
+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}
%************************************************************************
%* *
-%* Top-level bindings
+\subsubsection{ Top-level bindings}
%* *
%************************************************************************
contains bindings for the binders of this particular binding.
\begin{code}
-rnTopBinds :: RdrNameHsBinds -> RnMS s (RenamedHsBinds, FreeVars)
+rnTopBinds :: RdrNameHsBinds -> RnMS (RenamedHsBinds, FreeVars)
rnTopBinds EmptyBinds = returnRn (EmptyBinds, emptyFVs)
rnTopBinds (MonoBind bind sigs _) = rnTopMonoBinds bind sigs
rnTopMonoBinds mbinds sigs
= mapRn lookupBndrRn binder_rdr_names `thenRn` \ binder_names ->
let
- binder_set = mkNameSet binder_names
+ binder_set = mkNameSet binder_names
+ binder_occ_fm = listToFM [(nameOccName x,x) | x <- binder_names]
in
- rn_mono_binds TopLevel binder_set mbinds sigs
+ 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}
%************************************************************************
%* *
%************************************************************************
-@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
+\subsubsection{Nested binds}
+@rnMonoBinds@
+\begin{itemize}
+\item collects up the binders for this declaration group,
+\item checks that they form a set
+\item extends the environment to bind them to new local names
+\item calls @rnMonoBinds@ to do the real work
+\end{itemize}
+%
\begin{code}
rnBinds :: RdrNameHsBinds
- -> (RenamedHsBinds -> RnMS s (result, FreeVars))
- -> RnMS s (result, FreeVars)
+ -> (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 s (result, FreeVars))
- -> RnMS s (result, FreeVars)
+rnMonoBinds :: RdrNameMonoBinds
+ -> [RdrNameSig]
+ -> (RenamedHsBinds -> RnMS (result, FreeVars))
+ -> RnMS (result, FreeVars)
rnMonoBinds EmptyMonoBinds sigs thing_inside = thing_inside EmptyBinds
= -- 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 "binding group") mbinders_w_srclocs $ \ new_mbinders ->
+ bindLocatedLocalsRn (text "a binding group") mbinders_w_srclocs
+ $ \ new_mbinders ->
let
- binder_set = mkNameSet new_mbinders
+ 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
- rn_mono_binds NotTopLevel
- binder_set mbinds sigs `thenRn` \ (binds,bind_fvs) ->
+ -- 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) ->
+ -- 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
+ all_fvs = result_fvs `plusFV` bind_fvs `plusFV` sig_fvs
unused_binders = nameSetToList (binder_set `minusNameSet` all_fvs)
in
- warnUnusedBinds unused_binders `thenRn_`
+ warnUnusedLocalBinds unused_binders `thenRn_`
returnRn (result, delListFromNameSet all_fvs new_mbinders)
where
mbinders_w_srclocs = bagToList (collectMonoBinders mbinds)
%************************************************************************
%* *
-%* MonoBinds -- the main work is done here
+\subsubsection{ MonoBinds -- the main work is done here}
%* *
%************************************************************************
-@rnMonoBinds@ is used by *both* top-level and nested bindings. It
-assumes that all variables bound in this group are already in scope.
-This is done *either* by pass 3 (for the top-level bindings), *or* by
-@rnNestedMonoBinds@ (for the nested ones).
+@rn_mono_binds@ is used by {\em both} top-level and nested bindings.
+It assumes that all variables bound in this group are already in scope.
+This is done {\em either} by pass 3 (for the top-level bindings),
+{\em or} by @rnMonoBinds@ (for the nested ones).
\begin{code}
-rn_mono_binds :: TopLevelFlag
- -> NameSet -- Binders of this group
+rn_mono_binds :: [RenamedSig] -- Signatures attached to this group
-> RdrNameMonoBinds
- -> [RdrNameSig] -- Signatures attached to this group
- -> RnMS s (RenamedHsBinds, --
+ -> RnMS (RenamedHsBinds, --
FreeVars) -- Free variables
-rn_mono_binds top_lev binders mbinds sigs
+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
- renameSigs top_lev False binders sigs `thenRn` \ siglist ->
flattenMonoBinds siglist mbinds `thenRn` \ mbinds_info ->
-- Do the SCC analysis
- let edges = mkEdges (mbinds_info `zip` [(0::Int)..])
+ let
+ edges = mkEdges (mbinds_info `zip` [(0::Int)..])
scc_result = stronglyConnComp edges
final_binds = foldr1 ThenBinds (map reconstructCycle scc_result)
@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 \fbox{\ ???\ }
+
\begin{code}
flattenMonoBinds :: [RenamedSig] -- Signatures
-> RdrNameMonoBinds
- -> RnMS s [FlatMonoBindsInfo]
+ -> RnMS [FlatMonoBindsInfo]
flattenMonoBinds sigs EmptyMonoBinds = returnRn []
let
names_bound_here = mkNameSet (collectPatBinders pat')
sigs_for_me = sigsForMe (`elemNameSet` names_bound_here) sigs
- sigs_fvs = foldr sig_fv emptyFVs sigs_for_me
- fixity_sigs = [(name,sig) | FixSig sig@(FixitySig name _ _) <- sigs_for_me]
in
- extendFixityEnv fixity_sigs $
rnGRHSs grhss `thenRn` \ (grhss', fvs) ->
returnRn
[(names_bound_here,
- fvs `plusFV` sigs_fvs `plusFV` pat_fvs,
+ fvs `plusFV` pat_fvs,
PatMonoBind pat' grhss' locn,
sigs_for_me
)]
flattenMonoBinds sigs (FunMonoBind name inf matches locn)
= pushSrcLocRn locn $
- lookupBndrRn name `thenRn` \ name' ->
+ lookupBndrRn name `thenRn` \ new_name ->
let
- sigs_for_me = sigsForMe (name' ==) sigs
- sigs_fvs = foldr sig_fv emptyFVs sigs_for_me
- fixity_sigs = [(name,sig) | FixSig sig@(FixitySig name _ _) <- sigs_for_me]
+ sigs_for_me = sigsForMe (new_name ==) sigs
in
- extendFixityEnv fixity_sigs $
- mapAndUnzipRn rnMatch matches `thenRn` \ (new_matches, fv_lists) ->
- mapRn (checkPrecMatch inf name') new_matches `thenRn_`
+ mapFvRn rnMatch matches `thenRn` \ (new_matches, fvs) ->
+ mapRn_ (checkPrecMatch inf new_name) new_matches `thenRn_`
returnRn
- [(unitNameSet name',
- plusFVs fv_lists `plusFV` sigs_fvs,
- FunMonoBind name' inf new_matches locn,
+ [(unitNameSet new_name,
+ fvs,
+ FunMonoBind new_name inf new_matches locn,
sigs_for_me
)]
\end{code}
-@rnMethodBinds@ is used for the method bindings of an instance
-declaration. like @rnMonoBinds@ but without dependency analysis.
+@rnMethodBinds@ is used for the method bindings of a class and an instance
+declaration. Like @rnMonoBinds@ but without dependency analysis.
+
+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}
-rnMethodBinds :: RdrNameMonoBinds -> RnMS s (RenamedMonoBinds, FreeVars)
+rnMethodBinds :: RdrNameMonoBinds -> RnMS (RenamedMonoBinds, FreeVars)
rnMethodBinds EmptyMonoBinds = returnRn (EmptyMonoBinds, emptyFVs)
lookupGlobalOccRn name `thenRn` \ sel_name ->
-- We use the selector name as the binder
- mapAndUnzipRn rnMatch matches `thenRn` \ (new_matches, fvs_s) ->
- mapRn (checkPrecMatch inf sel_name) new_matches `thenRn_`
- returnRn (FunMonoBind sel_name inf new_matches locn, plusFVs fvs_s)
+ mapFvRn rnMatch matches `thenRn` \ (new_matches, fvs) ->
+ mapRn_ (checkPrecMatch inf sel_name) new_matches `thenRn_`
+ returnRn (FunMonoBind sel_name inf new_matches locn, fvs `addOneFV` sel_name)
rnMethodBinds (PatMonoBind (VarPatIn name) grhss locn)
= pushSrcLocRn locn $
- lookupGlobalOccRn name `thenRn` \ sel_name ->
+ lookupGlobalOccRn name `thenRn` \ sel_name ->
rnGRHSs grhss `thenRn` \ (grhss', fvs) ->
- returnRn (PatMonoBind (VarPatIn sel_name) grhss' locn, fvs)
+ returnRn (PatMonoBind (VarPatIn sel_name) grhss' locn, fvs `addOneFV` sel_name)
-- Can't handle method pattern-bindings which bind multiple methods.
rnMethodBinds mbind@(PatMonoBind other_pat _ locn)
failWithRn (EmptyMonoBinds, emptyFVs) (methodBindErr mbind)
\end{code}
-\begin{code}
--- If a SPECIALIZE pragma is of the "... = blah" form,
--- then we'd better make sure "blah" is taken into
--- acct in the dependency analysis (or we get an
--- unexpected out-of-scope error)! WDP 95/07
-
-sig_fv (SpecSig _ _ (Just blah) _) acc = acc `plusFV` unitFV blah
-sig_fv _ acc = acc
-\end{code}
%************************************************************************
%* *
%************************************************************************
%* *
-%* Manipulating FlatMonoBindInfo *
+\subsubsection{ Manipulating FlatMonoBindInfo}
%* *
%************************************************************************
%* *
%************************************************************************
-@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.
-
+@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
-sigatures. We'd only need this if we wanted to report unused tyvars.
+signatures. We'd only need this if we wanted to report unused tyvars.
\begin{code}
-renameSigs :: TopLevelFlag
- -> Bool -- True <-> sigs for an instance decl
- -- hence SPECIALISE instance prags ok
- -> NameSet -- Set of names bound in this group
+renameSigs :: Bool -- True => warn if (required) type signatures are missing.
+ -> NameSet -- Set of names bound in this group
+ -> (RdrName -> RnMS Name)
-> [RdrNameSig]
- -> RnMS s [RenamedSig] -- List of Sig constructors
+ -> RnMS ([RenamedSig], FreeVars) -- List of Sig constructors
-renameSigs top_lev inst_decl binders sigs
+renameSigs sigs_required binders lookup_occ_nm sigs
= -- Rename the signatures
- mapRn renameSig sigs `thenRn` \ sigs' ->
+ mapFvRn (renameSig lookup_occ_nm) sigs `thenRn` \ (sigs', fvs) ->
-- Check for (a) duplicate signatures
-- (b) signatures for things not in this group
let
(goodies, dups) = removeDups cmp_sig (sigsForMe (not . isUnboundName) sigs')
not_this_group = sigsForMe (not . (`elemNameSet` binders)) goodies
- spec_inst_sigs = [s | s@(SpecInstSig _ _) <- goodies]
type_sig_vars = [n | Sig n _ _ <- goodies]
- fixes = [f | f@(FixSig _) <- goodies]
- idecl_type_sigs = [s | s@(Sig _ _ _) <- goodies]
- sigs_required = case top_lev of {TopLevel -> opt_WarnMissingSigs; NotTopLevel -> False}
un_sigd_binders | sigs_required = nameSetToList binders `minusList` type_sig_vars
| otherwise = []
in
- mapRn dupSigDeclErr dups `thenRn_`
- mapRn unknownSigErr not_this_group `thenRn_`
- (if not inst_decl then
- mapRn unknownSigErr spec_inst_sigs
- else
- -- We're being strict here, outlawing the presence
- -- of type signatures within an instance declaration.
- mapRn unknownSigErr (fixes ++ idecl_type_sigs)
- ) `thenRn_`
- mapRn (addWarnRn.missingSigWarn) un_sigd_binders `thenRn_`
-
- returnRn sigs' -- bad ones and all:
- -- we need bindings of *some* sort for every name
-
-
-renameSig (Sig v ty src_loc)
+ 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 $
- lookupBndrRn v `thenRn` \ new_v ->
- rnHsSigType (quotes (ppr v)) ty `thenRn` \ (new_ty,_) ->
- returnRn (Sig new_v new_ty 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)
+renameSig _ (SpecInstSig ty src_loc)
= pushSrcLocRn src_loc $
- rnHsSigType (text "A SPECIALISE instance pragma") ty `thenRn` \ (new_ty, _) ->
- returnRn (SpecInstSig new_ty src_loc)
+ rnHsSigType (text "A SPECIALISE instance pragma") ty `thenRn` \ (new_ty, fvs) ->
+ returnRn (SpecInstSig new_ty src_loc, fvs)
-renameSig (SpecSig v ty using src_loc)
+renameSig lookup_occ_nm (SpecSig v ty src_loc)
= pushSrcLocRn src_loc $
- lookupBndrRn v `thenRn` \ new_v ->
- rnHsSigType (quotes (ppr v)) ty `thenRn` \ (new_ty,_) ->
- rn_using using `thenRn` \ new_using ->
- returnRn (SpecSig new_v new_ty new_using src_loc)
- where
- rn_using Nothing = returnRn Nothing
- rn_using (Just x) = lookupOccRn x `thenRn` \ new_x ->
- returnRn (Just new_x)
+ 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 (InlineSig v src_loc)
+renameSig lookup_occ_nm (FixSig (FixitySig v fix src_loc))
= pushSrcLocRn src_loc $
- lookupBndrRn v `thenRn` \ new_v ->
- returnRn (InlineSig new_v src_loc)
+ lookup_occ_nm v `thenRn` \ new_v ->
+ returnRn (FixSig (FixitySig new_v fix src_loc), unitFV new_v)
-renameSig (FixSig (FixitySig v fix src_loc))
+renameSig lookup_occ_nm (InlineSig v p src_loc)
= pushSrcLocRn src_loc $
- lookupBndrRn v `thenRn` \ new_v ->
- returnRn (FixSig (FixitySig new_v fix src_loc))
+ lookup_occ_nm v `thenRn` \ new_v ->
+ returnRn (InlineSig new_v p src_loc, unitFV new_v)
-renameSig (NoInlineSig v src_loc)
+renameSig lookup_occ_nm (NoInlineSig v p src_loc)
= pushSrcLocRn src_loc $
- lookupBndrRn v `thenRn` \ new_v ->
- returnRn (NoInlineSig new_v src_loc)
+ lookup_occ_nm v `thenRn` \ new_v ->
+ returnRn (NoInlineSig new_v p 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 _ _)
+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...
+ -- 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
| 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 (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)"
\begin{code}
dupSigDeclErr (sig:sigs)
= pushSrcLocRn loc $
- addErrRn (sep [ptext SLIT("Duplicate"),
- ptext what_it_is <> colon,
+ addErrRn (sep [ptext SLIT("Duplicate") <+> ptext what_it_is <> colon,
ppr sig])
where
(what_it_is, loc) = sig_doc sig
(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 (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)