import IfaceEnv
import BuildTyCl
import TcRnMonad
+import TcType ( tcSplitSigmaTy )
import Type
import TypeRep
import HscTypes
import DynFlags
import Util
import FastString
+import BasicTypes (Arity)
import Control.Monad
import Data.List
-- Entry point for *source-code* uses of importDecl
tcImportDecl name
| Just thing <- wiredInNameTyThing_maybe name
- = do { initIfaceTcRn (loadWiredInHomeIface name)
- -- See Note [Loading instances] in LoadIface
+ = do { when (needWiredInHomeIface thing)
+ (initIfaceTcRn (loadWiredInHomeIface name))
+ -- See Note [Loading instances for wired-in things]
; return thing }
| otherwise
= do { traceIf (text "tcImportDecl" <+> ppr name)
Succeeded thing -> return thing
Failed err -> failWithTc err }
-checkWiredInTyCon :: TyCon -> TcM ()
--- Ensure that the home module of the TyCon (and hence its instances)
--- are loaded. See See Note [Loading instances] in LoadIface
--- It might not be a wired-in tycon (see the calls in TcUnify),
--- in which case this is a no-op.
-checkWiredInTyCon tc
- | not (isWiredInName tc_name)
- = return ()
- | otherwise
- = do { mod <- getModule
- ; ASSERT( isExternalName tc_name )
- unless (mod == nameModule tc_name)
- (initIfaceTcRn (loadWiredInHomeIface tc_name))
- -- Don't look for (non-existent) Float.hi when
- -- compiling Float.lhs, which mentions Float of course
- -- A bit yukky to call initIfaceTcRn here
- }
- where
- tc_name = tyConName tc
-
importDecl :: Name -> IfM lcl (MaybeErr Message TyThing)
-- Get the TyThing for this Name from an interface file
-- It's not a wired-in thing -- the caller caught that
%************************************************************************
%* *
+ Checks for wired-in things
+%* *
+%************************************************************************
+
+Note [Loading instances for wired-in things]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+We need to make sure that we have at least *read* the interface files
+for any module with an instance decl or RULE that we might want.
+
+* If the instance decl is an orphan, we have a whole separate mechanism
+ (loadOprhanModules)
+
+* If the instance decl not an orphan, then the act of looking at the
+ TyCon or Class will force in the defining module for the
+ TyCon/Class, and hence the instance decl
+
+* BUT, if the TyCon is a wired-in TyCon, we don't really need its interface;
+ but we must make sure we read its interface in case it has instances or
+ rules. That is what LoadIface.loadWiredInHomeInterface does. It's called
+ from TcIface.{tcImportDecl, checkWiredInTyCon, ifCheckWiredInThing}
+
+* HOWEVER, only do this for TyCons. There are no wired-in Classes. There
+ are some wired-in Ids, but we don't want to load their interfaces. For
+ example, Control.Exception.Base.recSelError is wired in, but that module
+ is compiled late in the base library, and we don't want to force it to
+ load before it's been compiled!
+
+All of this is done by the type checker. The renamer plays no role.
+(It used to, but no longer.)
+
+
+\begin{code}
+checkWiredInTyCon :: TyCon -> TcM ()
+-- Ensure that the home module of the TyCon (and hence its instances)
+-- are loaded. See Note [Loading instances for wired-in things]
+-- It might not be a wired-in tycon (see the calls in TcUnify),
+-- in which case this is a no-op.
+checkWiredInTyCon tc
+ | not (isWiredInName tc_name)
+ = return ()
+ | otherwise
+ = do { mod <- getModule
+ ; ASSERT( isExternalName tc_name )
+ when (mod /= nameModule tc_name)
+ (initIfaceTcRn (loadWiredInHomeIface tc_name))
+ -- Don't look for (non-existent) Float.hi when
+ -- compiling Float.lhs, which mentions Float of course
+ -- A bit yukky to call initIfaceTcRn here
+ }
+ where
+ tc_name = tyConName tc
+
+ifCheckWiredInThing :: TyThing -> IfL ()
+-- Even though we are in an interface file, we want to make
+-- sure the instances of a wired-in thing are loaded (imagine f :: Double -> Double)
+-- Ditto want to ensure that RULES are loaded too
+-- See Note [Loading instances for wired-in things]
+ifCheckWiredInThing thing
+ = do { mod <- getIfModule
+ -- Check whether we are typechecking the interface for this
+ -- very module. E.g when compiling the base library in --make mode
+ -- we may typecheck GHC.Base.hi. At that point, GHC.Base is not in
+ -- the HPT, so without the test we'll demand-load it into the PIT!
+ -- C.f. the same test in checkWiredInTyCon above
+ ; let name = getName thing
+ ; ASSERT2( isExternalName name, ppr name )
+ when (needWiredInHomeIface thing && mod /= nameModule name)
+ (loadWiredInHomeIface name) }
+
+needWiredInHomeIface :: TyThing -> Bool
+-- Only for TyCons; see Note [Loading instances for wired-in things]
+needWiredInHomeIface (ATyCon {}) = True
+needWiredInHomeIface _ = False
+\end{code}
+
+%************************************************************************
+%* *
Type-checking a complete interface
%* *
%************************************************************************
-> IfaceDecl
-> IfL TyThing
-tcIfaceDecl ignore_prags (IfaceId {ifName = occ_name, ifType = iface_type, ifIdInfo = info})
+tcIfaceDecl ignore_prags (IfaceId {ifName = occ_name, ifType = iface_type,
+ ifIdDetails = details, ifIdInfo = info})
= do { name <- lookupIfaceTop occ_name
; ty <- tcIfaceType iface_type
+ ; details <- tcIdDetails ty details
; info <- tcIdInfo ignore_prags name ty info
- ; return (AnId (mkVanillaGlobalWithInfo name ty info)) }
+ ; return (AnId (mkGlobalId details name ty info)) }
tcIfaceDecl _ (IfaceData {ifName = occ_name,
ifTyVars = tv_bndrs,
; sigs <- mapM tc_sig rdr_sigs
; fds <- mapM tc_fd rdr_fds
; ats' <- mapM (tcIfaceDecl ignore_prags) rdr_ats
- ; let ats = zipWith setTyThingPoss ats' (map ifTyVars rdr_ats)
+ ; let ats = map (setAssocFamilyPermutation tyvars) ats'
; cls <- buildClass ignore_prags cls_name tyvars ctxt fds ats sigs tc_isrec
; return (AClass cls) }
where
; tvs2' <- mapM tcIfaceTyVar tvs2
; return (tvs1', tvs2') }
- -- For each AT argument compute the position of the corresponding class
- -- parameter in the class head. This will later serve as a permutation
- -- vector when checking the validity of instance declarations.
- setTyThingPoss (ATyCon tycon) atTyVars =
- let classTyVars = map fst tv_bndrs
- poss = catMaybes
- . map ((`elemIndex` classTyVars) . fst)
- $ atTyVars
- -- There will be no Nothing, as we already passed renaming
- in
- ATyCon (setTyConArgPoss tycon poss)
- setTyThingPoss _ _ = panic "TcIface.setTyThingPoss"
-
tcIfaceDecl _ (IfaceForeign {ifName = rdr_name, ifExtName = ext_name})
= do { name <- lookupIfaceTop rdr_name
; return (ATyCon (mkForeignTyCon name ext_name
tcIfaceExpr (IfaceNote note expr) = do
expr' <- tcIfaceExpr expr
case note of
+ IfaceInlineMe -> return (Note InlineMe expr')
IfaceSCC cc -> return (Note (SCC cc) expr')
IfaceCoreNote n -> return (Note (CoreNote n) expr')
%************************************************************************
\begin{code}
+tcIdDetails :: Type -> IfaceIdDetails -> IfL IdDetails
+tcIdDetails _ IfVanillaId = return VanillaId
+tcIdDetails _ IfDFunId = return DFunId
+tcIdDetails ty (IfRecSelId naughty)
+ = return (RecSelId { sel_tycon = tc, sel_naughty = naughty })
+ where
+ (_, _, tau) = tcSplitSigmaTy ty
+ tc = tyConAppTyCon (funArgTy tau)
+ -- A bit fragile. Relies on the selector type looking like
+ -- forall abc. (stupid-context) => T a b c -> blah
+
tcIdInfo :: Bool -> Name -> Type -> IfaceIdInfo -> IfL IdInfo
tcIdInfo ignore_prags name ty info
| ignore_prags = return vanillaIdInfo
tcPrag info HsNoCafRefs = return (info `setCafInfo` NoCafRefs)
tcPrag info (HsArity arity) = return (info `setArityInfo` arity)
tcPrag info (HsStrictness str) = return (info `setAllStrictnessInfo` Just str)
- tcPrag info (HsInline prag) = return (info `setInlinePragInfo` prag)
-- The next two are lazy, so they don't transitively suck stuff in
- tcPrag info (HsUnfold if_unf) = do { unf <- tcUnfolding name ty info if_unf
- ; return (info `setUnfoldingInfoLazily` unf) }
+ tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
+ tcPrag info (HsInline inline_prag) = return (info `setInlinePragInfo` inline_prag)
+ tcPrag info (HsUnfold expr) = do
+ maybe_expr' <- tcPragExpr name expr
+ let
+ -- maybe_expr' doesn't get looked at if the unfolding
+ -- is never inspected; so the typecheck doesn't even happen
+ unfold_info = case maybe_expr' of
+ Nothing -> noUnfolding
+ Just expr' -> mkTopUnfolding expr'
+ return (info `setUnfoldingInfoLazily` unfold_info)
\end{code}
\begin{code}
-tcUnfolding :: Name -> Type -> IdInfo -> IfaceUnfolding -> IfL Unfolding
-tcUnfolding name _ _ (IfCoreUnfold if_expr)
- = do { mb_expr <- tcPragExpr name if_expr
- ; return (case mb_expr of
- Nothing -> NoUnfolding
- Just expr -> mkTopUnfolding expr) }
-
-tcUnfolding name _ _ (IfInlineRule arity if_expr)
- = do { mb_expr <- tcPragExpr name if_expr
- ; return (case mb_expr of
- Nothing -> NoUnfolding
- Just expr -> mkInlineRule expr arity) }
-
-tcUnfolding name ty info (IfWrapper arity wkr)
+tcWorkerInfo :: Type -> IdInfo -> Name -> Arity -> IfL IdInfo
+tcWorkerInfo ty info wkr arity
= do { mb_wkr_id <- forkM_maybe doc (tcIfaceExtId wkr)
+
+ -- We return without testing maybe_wkr_id, but as soon as info is
+ -- looked at we will test it. That's ok, because its outside the
+ -- knot; and there seems no big reason to further defer the
+ -- tcIfaceId lookup. (Contrast with tcPragExpr, where postponing walking
+ -- over the unfolding until it's actually used does seem worth while.)
; us <- newUniqueSupply
+
; return (case mb_wkr_id of
- Nothing -> noUnfolding
- Just wkr_id -> make_inline_rule wkr_id us) }
+ Nothing -> info
+ Just wkr_id -> add_wkr_info us wkr_id info) }
where
- doc = text "Worker for" <+> ppr name
+ doc = text "Worker for" <+> ppr wkr
+ add_wkr_info us wkr_id info
+ = info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
+ `setWorkerInfo` HasWorker wkr_id arity
- make_inline_rule wkr_id us
- = mkWwInlineRule (initUs_ us (mkWrapper ty strict_sig) wkr_id)
- arity wkr_id
+ mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
-- We are relying here on strictness info always appearing
-- before worker info, fingers crossed ....
tcIfaceGlobal name
| Just thing <- wiredInNameTyThing_maybe name
-- Wired-in things include TyCons, DataCons, and Ids
- = do { ifCheckWiredInThing name; return thing }
+ = do { ifCheckWiredInThing thing; return thing }
| otherwise
= do { env <- getGblEnv
; case if_rec_types env of { -- Note [Tying the knot]
-- Because if M.hs also has M.hs-boot, M.T will *already be* in the HPT, but in its
-- emasculated form (e.g. lacking data constructors).
-ifCheckWiredInThing :: Name -> IfL ()
--- Even though we are in an interface file, we want to make
--- sure the instances of a wired-in thing are loaded (imagine f :: Double -> Double)
--- Ditto want to ensure that RULES are loaded too
--- See Note [Loading instances] in LoadIface
-ifCheckWiredInThing name
- = do { mod <- getIfModule
- -- Check whether we are typechecking the interface for this
- -- very module. E.g when compiling the base library in --make mode
- -- we may typecheck GHC.Base.hi. At that point, GHC.Base is not in
- -- the HPT, so without the test we'll demand-load it into the PIT!
- -- C.f. the same test in checkWiredInTyCon above
- ; ASSERT2( isExternalName name, ppr name )
- unless (mod == nameModule name)
- (loadWiredInHomeIface name) }
-
tcIfaceTyCon :: IfaceTyCon -> IfL TyCon
tcIfaceTyCon IfaceIntTc = tcWiredInTyCon intTyCon
tcIfaceTyCon IfaceBoolTc = tcWiredInTyCon boolTyCon
-- sure the instances and RULES of this tycon are loaded
-- Imagine: f :: Double -> Double
tcWiredInTyCon :: TyCon -> IfL TyCon
-tcWiredInTyCon tc = do { ifCheckWiredInThing (tyConName tc)
+tcWiredInTyCon tc = do { ifCheckWiredInThing (ATyCon tc)
; return tc }
tcIfaceClass :: Name -> IfL Class
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