-%
+
+% (c) The University of Glasgow 2006
% (c) The GRASP Project, Glasgow University, 1992-2002
%
\begin{code}
+{-# OPTIONS -w #-}
+-- 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
+-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
module TcRnTypes(
TcRnIf, TcRn, TcM, RnM, IfM, IfL, IfG, -- The monad is opaque outside this module
TcRef,
IfGblEnv(..), IfLclEnv(..),
-- Ranamer types
- ErrCtxt,
+ ErrCtxt, RecFieldEnv,
ImportAvails(..), emptyImportAvails, plusImportAvails,
- plusAvail, pruneAvails,
- AvailEnv, emptyAvailEnv, unitAvailEnv, plusAvailEnv,
- mkAvailEnv, lookupAvailEnv, lookupAvailEnv_maybe, availEnvElts, addAvail,
WhereFrom(..), mkModDeps,
-- Typechecker types
- TcTyThing(..), pprTcTyThingCategory,
+ TcTyThing(..), pprTcTyThingCategory, RefinementVisibility(..),
-- Template Haskell
ThStage(..), topStage, topSpliceStage,
ArrowCtxt(NoArrowCtxt), newArrowScope, escapeArrowScope,
-- Insts
- Inst(..), InstOrigin(..), InstLoc(..), pprInstLoc,
- instLocSrcLoc, instLocSrcSpan,
- LIE, emptyLIE, unitLIE, plusLIE, consLIE,
+ Inst(..), InstOrigin(..), InstLoc(..),
+ pprInstLoc, pprInstArising, instLocSpan, instLocOrigin,
+ LIE, emptyLIE, unitLIE, plusLIE, consLIE, instLoc, instSpan,
plusLIEs, mkLIE, isEmptyLIE, lieToList, listToLIE,
-- Misc other types
- TcId, TcIdSet, TcDictBinds
+ TcId, TcIdSet, TcDictBinds,
+
) where
#include "HsVersions.h"
-import HsSyn ( PendingSplice, HsOverLit, LRuleDecl, LForeignDecl,
- ArithSeqInfo, DictBinds, LHsBinds, LImportDecl, HsGroup,
- HsWrapper, IE, HsDoc, HaddockModInfo )
-import HscTypes ( FixityEnv,
- HscEnv, TypeEnv, TyThing,
- GenAvailInfo(..), AvailInfo, HscSource(..),
- availName, IsBootInterface, Deprecations )
-import Packages ( PackageId )
-import Type ( Type, pprTyThingCategory )
-import TcType ( TcTyVarSet, TcType, TcThetaType, SkolemInfo,
- TcPredType, TcKind, tcCmpPred, tcCmpType,
- tcCmpTypes, pprSkolInfo )
-import InstEnv ( Instance, InstEnv )
-import FamInstEnv ( FamInst, FamInstEnv )
+import HsSyn hiding (LIE)
+import HscTypes
+import Packages
+import Type
+import Coercion
+import TcType
+import TcGadt
+import InstEnv
+import FamInstEnv
import IOEnv
-import RdrName ( GlobalRdrEnv, LocalRdrEnv )
-import Name ( Name )
+import RdrName
+import Name
import NameEnv
-import NameSet ( NameSet, unionNameSets, DefUses )
-import Var ( Id, TyVar )
-import VarEnv ( TidyEnv )
+import NameSet
+import Var
+import VarEnv
import Module
import UniqFM
-import SrcLoc ( SrcSpan, SrcLoc, Located, srcSpanStart )
-import VarSet ( IdSet )
-import ErrUtils ( Messages, Message )
-import UniqSupply ( UniqSupply )
-import BasicTypes ( IPName )
-import Util ( thenCmp )
+import SrcLoc
+import VarSet
+import ErrUtils
+import UniqSupply
+import BasicTypes
+import Util
import Bag
import Outputable
-import Maybe ( mapMaybe )
-import ListSetOps ( unionLists )
-import Data.List ( nub )
+import ListSetOps
+import FiniteMap
+
+import Data.Maybe
+import Data.List
\end{code}
env_gbl :: gbl, -- Info about things defined at the top level
-- of the module being compiled
- env_lcl :: lcl -- Nested stuff; changes as we go into
- -- an expression
+ env_lcl :: lcl -- Nested stuff; changes as we go into
}
-- TcGblEnv describes the top-level of the module at the
tcg_default :: Maybe [Type], -- Types used for defaulting
-- Nothing => no 'default' decl
- tcg_fix_env :: FixityEnv, -- Just for things in this module
+ tcg_fix_env :: FixityEnv, -- Just for things in this module
+ tcg_field_env :: RecFieldEnv, -- Just for things in this module
tcg_type_env :: TypeEnv, -- Global type env for the module we are compiling now
-- All TyCons and Classes (for this module) end up in here right away,
-- (Ids defined in this module start in the local envt,
-- though they move to the global envt during zonking)
- tcg_type_env_var :: TcRef TypeEnv,
+ tcg_type_env_var :: TcRef TypeEnv,
-- Used only to initialise the interface-file
-- typechecker in initIfaceTcRn, so that it can see stuff
-- bound in this module when dealing with hi-boot recursions
tcg_fords :: [LForeignDecl Id], -- ...Foreign import & exports
tcg_doc :: Maybe (HsDoc Name), -- Maybe Haddock documentation
- tcg_hmi :: HaddockModInfo Name -- Haddock module information
+ tcg_hmi :: HaddockModInfo Name, -- Haddock module information
+ tcg_hpc :: AnyHpcUsage -- True if any part of the prog uses hpc instrumentation.
}
+
+type RecFieldEnv = NameEnv [Name] -- Maps a constructor name *in this module*
+ -- to the fields for that constructor
+ -- This is used when dealing with ".." notation in record
+ -- construction and pattern matching.
+ -- The FieldEnv deals *only* with constructors defined in
+ -- *thie* module. For imported modules, we get the same info
+ -- from the TypeEnv
\end{code}
%************************************************************************
-- Incremented when going inside a bracket,
-- decremented when going inside a splice
-- NB: ThLevel is one greater than the 'n' in Fig 2 of the
- -- original "Template meta-programmign for Haskell" paper
+ -- original "Template meta-programming for Haskell" paper
impLevel, topLevel :: ThLevel
topLevel = 1 -- Things defined at top level of this module
| ATcId { -- Ids defined in this module; may not be fully zonked
tct_id :: TcId,
- tct_co :: Maybe HsWrapper, -- Nothing <=> Do not apply a GADT type refinement
+ tct_co :: RefinementVisibility, -- Previously: Maybe HsWrapper
+ -- Nothing <=> Do not apply a GADT type refinement
-- I am wobbly, or have no free
-- type variables
-- Just co <=> Apply any type refinement to me,
| AThing TcKind -- Used temporarily, during kind checking, for the
-- tycons and clases in this recursive group
+data RefinementVisibility
+ = Unrefineable -- Do not apply a GADT refinement
+ -- I have no free variables
+
+ | Rigid HsWrapper -- Apply any refinement to me
+ -- and record it in the coercion
+
+ | Wobbly -- Do not apply a GADT refinement
+ -- I am wobbly
+
+ | WobblyInvisible -- Wobbly type, not available inside current
+ -- GADT refinement
+
instance Outputable TcTyThing where -- Debugging only
- ppr (AGlobal g) = ppr g
+ ppr (AGlobal g) = pprTyThing g
ppr elt@(ATcId {}) = text "Identifier" <>
ifPprDebug (brackets (ppr (tct_id elt) <> dcolon <> ppr (tct_type elt) <> comma
<+> ppr (tct_level elt) <+> ppr (tct_co elt)))
pprTcTyThingCategory (ATyVar {}) = ptext SLIT("Type variable")
pprTcTyThingCategory (ATcId {}) = ptext SLIT("Local identifier")
pprTcTyThingCategory (AThing {}) = ptext SLIT("Kinded thing")
+
+instance Outputable RefinementVisibility where
+ ppr Unrefineable = ptext SLIT("unrefineable")
+ ppr (Rigid co) = ptext SLIT("rigid") <+> ppr co
+ ppr Wobbly = ptext SLIT("wobbly")
+ ppr WobblyInvisible = ptext SLIT("wobbly-invisible")
+
\end{code}
\begin{code}
It is used * when processing the export list
* when constructing usage info for the inteface file
* to identify the list of directly imported modules
- for initialisation purposes
+ for initialisation purposes and
+ for optimsed overlap checking of family instances
* when figuring out what things are really unused
\begin{code}
data ImportAvails
= ImportAvails {
- imp_env :: ModuleNameEnv [AvailInfo],
- -- All the things imported *unqualified*, classified by
- -- the *module qualifier* for its import
- -- e.g. import List as Foo
- -- would add a binding Foo |-> ...stuff from List...
- -- to imp_env.
- --
- -- This is exactly the list of things that will be exported
- -- by a 'module M' specifier in the export list.
- -- (see Haskell 98 Report Section 5.2).
- --
- -- Warning: there may be duplciates in this list,
- -- duplicates are removed at the use site (rnExports).
- -- We might consider turning this into a NameEnv at
- -- some point.
-
- imp_mods :: ModuleEnv (Module, Bool, SrcSpan),
+ imp_mods :: ModuleEnv (Module, [(ModuleName, Bool, SrcSpan)]),
-- Domain is all directly-imported modules
+ -- The ModuleName is what the module was imported as, e.g. in
+ -- import Foo as Bar
+ -- it is Bar.
-- Bool means:
-- True => import was "import Foo ()"
-- False => import was some other form
-- modules imported from other packages.
imp_orphs :: [Module],
- -- Orphan modules below us in the import tree
+ -- Orphan modules below us in the import tree (and maybe
+ -- including us for imported modules)
- imp_parent :: NameEnv AvailInfo
- -- for the names in scope in this module, tells us
- -- the relationship between parents and children
- -- (eg. a TyCon is the parent of its DataCons, a
- -- class is the parent of its methods, etc.).
+ imp_finsts :: [Module]
+ -- Family instance modules below us in the import tree (and
+ -- maybe including us for imported modules)
}
mkModDeps :: [(ModuleName, IsBootInterface)]
add env elt@(m,_) = addToUFM env m elt
emptyImportAvails :: ImportAvails
-emptyImportAvails = ImportAvails { imp_env = emptyUFM,
- imp_mods = emptyModuleEnv,
+emptyImportAvails = ImportAvails { imp_mods = emptyModuleEnv,
imp_dep_mods = emptyUFM,
imp_dep_pkgs = [],
imp_orphs = [],
- imp_parent = emptyNameEnv }
+ imp_finsts = [] }
plusImportAvails :: ImportAvails -> ImportAvails -> ImportAvails
plusImportAvails
- (ImportAvails { imp_env = env1, imp_mods = mods1,
+ (ImportAvails { imp_mods = mods1,
imp_dep_mods = dmods1, imp_dep_pkgs = dpkgs1,
- imp_orphs = orphs1, imp_parent = parent1 })
- (ImportAvails { imp_env = env2, imp_mods = mods2,
+ imp_orphs = orphs1, imp_finsts = finsts1 })
+ (ImportAvails { imp_mods = mods2,
imp_dep_mods = dmods2, imp_dep_pkgs = dpkgs2,
- imp_orphs = orphs2, imp_parent = parent2 })
- = ImportAvails { imp_env = plusUFM_C (++) env1 env2,
- imp_mods = mods1 `plusModuleEnv` mods2,
+ imp_orphs = orphs2, imp_finsts = finsts2 })
+ = ImportAvails { imp_mods = plusModuleEnv_C plus_mod mods1 mods2,
imp_dep_mods = plusUFM_C plus_mod_dep dmods1 dmods2,
imp_dep_pkgs = dpkgs1 `unionLists` dpkgs2,
imp_orphs = orphs1 `unionLists` orphs2,
- imp_parent = plusNameEnv_C plus_avails parent1 parent2 }
+ imp_finsts = finsts1 `unionLists` finsts2 }
where
- plus_avails (AvailTC tc subs1) (AvailTC _ subs2)
- = AvailTC tc (nub (subs1 ++ subs2))
- plus_avails avail _ = avail
-
+ plus_mod (m1, xs1) (_, xs2) = (m1, xs1 ++ xs2)
plus_mod_dep (m1, boot1) (m2, boot2)
= WARN( not (m1 == m2), (ppr m1 <+> ppr m2) $$ (ppr boot1 <+> ppr boot2) )
-- Check mod-names match
%************************************************************************
%* *
- Avails, AvailEnv, etc
-%* *
-v%************************************************************************
-
-\begin{code}
-plusAvail (Avail n1) (Avail n2) = Avail n1
-plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
--- Added SOF 4/97
-#ifdef DEBUG
-plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
-#endif
-
--------------------------
-pruneAvails :: (Name -> Bool) -- Keep if this is True
- -> [AvailInfo]
- -> [AvailInfo]
-pruneAvails keep avails
- = mapMaybe del avails
- where
- del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
- del (Avail n) | keep n = Just (Avail n)
- | otherwise = Nothing
- del (AvailTC n ns) | null ns' = Nothing
- | otherwise = Just (AvailTC n ns')
- where
- ns' = filter keep ns
-\end{code}
-
----------------------------------------
- AvailEnv and friends
----------------------------------------
-
-\begin{code}
-type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
-
-emptyAvailEnv :: AvailEnv
-emptyAvailEnv = emptyNameEnv
-
-unitAvailEnv :: AvailInfo -> AvailEnv
-unitAvailEnv a = unitNameEnv (availName a) a
-
-plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
-plusAvailEnv = plusNameEnv_C plusAvail
-
-lookupAvailEnv_maybe :: AvailEnv -> Name -> Maybe AvailInfo
-lookupAvailEnv_maybe = lookupNameEnv
-
-lookupAvailEnv :: AvailEnv -> Name -> AvailInfo
-lookupAvailEnv env n = case lookupNameEnv env n of
- Just avail -> avail
- Nothing -> pprPanic "lookupAvailEnv" (ppr n)
-
-availEnvElts = nameEnvElts
-
-addAvail :: AvailEnv -> AvailInfo -> AvailEnv
-addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
-
-mkAvailEnv :: [AvailInfo] -> AvailEnv
- -- 'avails' may have several items with the same availName
- -- E.g import Ix( Ix(..), index )
- -- will give Ix(Ix,index,range) and Ix(index)
- -- We want to combine these; addAvail does that
-mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
-\end{code}
-
-%************************************************************************
-%* *
\subsection{Where from}
%* *
%************************************************************************
Method 34 doubleId [Int] origin
+In addition to the basic Haskell variants of 'Inst's, they can now also
+represent implication constraints 'forall tvs. (reft, given) => wanted'
+and equality constraints 'co :: ty1 ~ ty2'.
+
+NB: Equalities occur in two flavours:
+
+ (1) Dict {tci_pred = EqPred ty1 ty2}
+ (2) EqInst {tci_left = ty1, tci_right = ty2, tci_co = coe}
+
+The former arises from equalities in contexts, whereas the latter is used
+whenever the type checker introduces an equality (e.g., during deferring
+unification).
+
+I am not convinced that this duplication is necessary or useful! -=chak
+
\begin{code}
data Inst
- = Dict
- Name
- TcPredType
- InstLoc
-
- | Method
- Id
-
- TcId -- The overloaded function
- -- This function will be a global, local, or ClassOpId;
- -- inside instance decls (only) it can also be an InstId!
- -- The id needn't be completely polymorphic.
- -- You'll probably find its name (for documentation purposes)
- -- inside the InstOrigin
-
- [TcType] -- The types to which its polymorphic tyvars
- -- should be instantiated.
- -- These types must saturate the Id's foralls.
-
- TcThetaType -- The (types of the) dictionaries to which the function
- -- must be applied to get the method
+ = Dict {
+ tci_name :: Name,
+ tci_pred :: TcPredType,
+ tci_loc :: InstLoc
+ }
- InstLoc
+ | ImplicInst { -- An implication constraint
+ -- forall tvs. (reft, given) => wanted
+ tci_name :: Name,
+ tci_tyvars :: [TcTyVar], -- Quantified type variables
+ -- Includes coercion variables
+ -- mentioned in tci_reft
+ tci_reft :: Refinement,
+ tci_given :: [Inst], -- Only Dicts and EqInsts
+ -- (no Methods, LitInsts, ImplicInsts)
+ tci_wanted :: [Inst], -- Only Dicts, EqInst, and ImplicInsts
+ -- (no Methods or LitInsts)
+
+ tci_loc :: InstLoc
+ }
+ -- NB: the tci_given are not necessarily rigid,
+ -- although they will be if the tci_reft is non-trivial
+ -- NB: the tci_reft is already applied to tci_given and tci_wanted
+
+ | Method {
+ tci_id :: TcId, -- The Id for the Inst
+
+ tci_oid :: TcId, -- The overloaded function
+ -- This function will be a global, local, or ClassOpId;
+ -- inside instance decls (only) it can also be an InstId!
+ -- The id needn't be completely polymorphic.
+ -- You'll probably find its name (for documentation purposes)
+ -- inside the InstOrigin
+
+ tci_tys :: [TcType], -- The types to which its polymorphic tyvars
+ -- should be instantiated.
+ -- These types must saturate the Id's foralls.
+
+ tci_theta :: TcThetaType,
+ -- The (types of the) dictionaries to which the function
+ -- must be applied to get the method
- -- INVARIANT 1: in (Method u f tys theta tau loc)
- -- type of (f tys dicts(from theta)) = tau
+ tci_loc :: InstLoc
+ }
+ -- INVARIANT 1: in (Method m f tys theta tau loc)
+ -- type of m = type of (f tys dicts(from theta))
- -- INVARIANT 2: tau must not be of form (Pred -> Tau)
+ -- INVARIANT 2: type of m must not be of form (Pred -> Tau)
-- Reason: two methods are considered equal if the
-- base Id matches, and the instantiating types
-- match. The TcThetaType should then match too.
-- This only bites in the call to tcInstClassOp in TcClassDcl.mkMethodBind
- | LitInst
- Name
- (HsOverLit Name) -- The literal from the occurrence site
- -- INVARIANT: never a rebindable-syntax literal
- -- Reason: tcSyntaxName does unification, and we
- -- don't want to deal with that during tcSimplify,
- -- when resolving LitInsts
- TcType -- The type at which the literal is used
- InstLoc
+ | LitInst {
+ tci_name :: Name,
+ tci_lit :: HsOverLit Name, -- The literal from the occurrence site
+ -- INVARIANT: never a rebindable-syntax literal
+ -- Reason: tcSyntaxName does unification, and we
+ -- don't want to deal with that during tcSimplify,
+ -- when resolving LitInsts
+
+ tci_ty :: TcType, -- The type at which the literal is used
+ tci_loc :: InstLoc
+ }
+
+ | EqInst { -- delayed unification of the form
+ -- co :: ty1 ~ ty2
+ tci_left :: TcType, -- ty1 -- both types are...
+ tci_right :: TcType, -- ty2 -- ...free of boxes
+ tci_co :: Either -- co
+ TcTyVar -- - a wanted equation, with a hole, to be
+ -- filled with a witness for the equality;
+ -- for equation arising from deferring
+ -- unification, 'ty1' is the actual and
+ -- 'ty2' the expected type
+ Coercion, -- - a given equation, with a coercion
+ -- witnessing the equality;
+ -- a coercion that originates from a
+ -- signature or a GADT is a CoVar, but
+ -- after normalisation of coercions, they
+ -- can be arbitrary Coercions involving
+ -- constructors and pseudo-constructors
+ -- like sym and trans.
+ tci_loc :: InstLoc,
+
+ tci_name :: Name -- Debugging help only: this makes it easier to
+ -- follow where a constraint is used in a morass
+ -- of trace messages! Unlike other Insts, it has
+ -- no semantic significance whatsoever.
+ }
\end{code}
@Insts@ are ordered by their class/type info, rather than by their
unique. This allows the context-reduction mechanism to use standard finite
-maps to do their stuff.
+maps to do their stuff. It's horrible that this code is here, rather
+than with the Avails handling stuff in TcSimplify
\begin{code}
instance Ord Inst where
EQ -> True
other -> False
-cmpInst (Dict _ pred1 _) (Dict _ pred2 _) = pred1 `tcCmpPred` pred2
-cmpInst (Dict _ _ _) other = LT
-
-cmpInst (Method _ _ _ _ _) (Dict _ _ _) = GT
-cmpInst (Method _ id1 tys1 _ _) (Method _ id2 tys2 _ _) = (id1 `compare` id2) `thenCmp` (tys1 `tcCmpTypes` tys2)
-cmpInst (Method _ _ _ _ _) other = LT
-
-cmpInst (LitInst _ _ _ _) (Dict _ _ _) = GT
-cmpInst (LitInst _ _ _ _) (Method _ _ _ _ _) = GT
-cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) = (lit1 `compare` lit2) `thenCmp` (ty1 `tcCmpType` ty2)
+cmpInst d1@(Dict {}) d2@(Dict {}) = tci_pred d1 `tcCmpPred` tci_pred d2
+cmpInst (Dict {}) other = LT
+
+cmpInst (Method {}) (Dict {}) = GT
+cmpInst m1@(Method {}) m2@(Method {}) = (tci_oid m1 `compare` tci_oid m2) `thenCmp`
+ (tci_tys m1 `tcCmpTypes` tci_tys m2)
+cmpInst (Method {}) other = LT
+
+cmpInst (LitInst {}) (Dict {}) = GT
+cmpInst (LitInst {}) (Method {}) = GT
+cmpInst l1@(LitInst {}) l2@(LitInst {}) = (tci_lit l1 `compare` tci_lit l2) `thenCmp`
+ (tci_ty l1 `tcCmpType` tci_ty l2)
+cmpInst (LitInst {}) other = LT
+
+ -- Implication constraints are compared by *name*
+ -- not by type; that is, we make no attempt to do CSE on them
+cmpInst (ImplicInst {}) (Dict {}) = GT
+cmpInst (ImplicInst {}) (Method {}) = GT
+cmpInst (ImplicInst {}) (LitInst {}) = GT
+cmpInst i1@(ImplicInst {}) i2@(ImplicInst {}) = tci_name i1 `compare` tci_name i2
+cmpInst (ImplicInst {}) other = LT
+
+ -- same for Equality constraints
+cmpInst (EqInst {}) (Dict {}) = GT
+cmpInst (EqInst {}) (Method {}) = GT
+cmpInst (EqInst {}) (LitInst {}) = GT
+cmpInst (EqInst {}) (ImplicInst {}) = GT
+cmpInst i1@(EqInst {}) i2@(EqInst {}) = tci_name i1 `compare` tci_name i2
\end{code}
unitLIE inst = unitBag inst
mkLIE insts = listToBag insts
plusLIE lie1 lie2 = lie1 `unionBags` lie2
-consLIE inst lie = inst `consBag` lie
plusLIEs lies = unionManyBags lies
lieToList = bagToList
listToLIE = listToBag
+
+consLIE inst lie = lie `snocBag` inst
+-- Putting the new Inst at the *end* of the bag is a half-hearted attempt
+-- to ensure that we tend to report the *leftmost* type-constraint error
+-- E.g. f :: [a]
+-- f = [1,2,3]
+-- we'd like to complain about the '1', not the '3'.
+--
+-- "Half-hearted" because the rest of the type checker makes no great
+-- claims for retaining order in the constraint set. Still, this
+-- seems to improve matters slightly. Exampes: mdofail001, tcfail015
\end{code}
functions that deal with it.
\begin{code}
+-------------------------------------------
data InstLoc = InstLoc InstOrigin SrcSpan ErrCtxt
-instLocSrcLoc :: InstLoc -> SrcLoc
-instLocSrcLoc (InstLoc _ src_span _) = srcSpanStart src_span
+instLoc :: Inst -> InstLoc
+instLoc inst = tci_loc inst
+
+instSpan :: Inst -> SrcSpan
+instSpan wanted = instLocSpan (instLoc wanted)
+
+instLocSpan :: InstLoc -> SrcSpan
+instLocSpan (InstLoc _ s _) = s
-instLocSrcSpan :: InstLoc -> SrcSpan
-instLocSrcSpan (InstLoc _ src_span _) = src_span
+instLocOrigin :: InstLoc -> InstOrigin
+instLocOrigin (InstLoc o _ _) = o
+pprInstArising :: Inst -> SDoc
+pprInstArising loc = ptext SLIT("arising from") <+> pprInstLoc (tci_loc loc)
+
+pprInstLoc :: InstLoc -> SDoc
+pprInstLoc (InstLoc orig span _) = sep [ppr orig, text "at" <+> ppr span]
+
+-------------------------------------------
data InstOrigin
= SigOrigin SkolemInfo -- Pattern, class decl, inst decl etc;
-- Places that bind type variables and introduce
-- The rest are all occurrences: Insts that are 'wanted'
-------------------------------------------------------
| OccurrenceOf Name -- Occurrence of an overloaded identifier
+ | SpecPragOrigin Name -- Specialisation pragma for identifier
| IPOccOrigin (IPName Name) -- Occurrence of an implicit parameter
| LiteralOrigin (HsOverLit Name) -- Occurrence of a literal
+ | NegateOrigin -- Occurrence of syntactic negation
| ArithSeqOrigin (ArithSeqInfo Name) -- [x..], [x..y] etc
| PArrSeqOrigin (ArithSeqInfo Name) -- [:x..y:] and [:x,y..z:]
+ | TupleOrigin -- (..,..)
| InstSigOrigin -- A dict occurrence arising from instantiating
-- a polymorphic type during a subsumption check
+ | ExprSigOrigin -- e :: ty
| RecordUpdOrigin
+ | ViewPatOrigin
| InstScOrigin -- Typechecking superclasses of an instance declaration
| DerivOrigin -- Typechecking deriving
| StandAloneDerivOrigin -- Typechecking stand-alone deriving
| DefaultOrigin -- Typechecking a default decl
| DoOrigin -- Arising from a do expression
| ProcOrigin -- Arising from a proc expression
-\end{code}
-
-\begin{code}
-pprInstLoc :: InstLoc -> SDoc
-pprInstLoc (InstLoc orig locn _)
- = sep [text "arising from" <+> pp_orig orig,
- text "at" <+> ppr locn]
- where
- pp_orig (OccurrenceOf name) = hsep [ptext SLIT("use of"), quotes (ppr name)]
- pp_orig (IPOccOrigin name) = hsep [ptext SLIT("use of implicit parameter"), quotes (ppr name)]
- pp_orig (IPBindOrigin name) = hsep [ptext SLIT("binding for implicit parameter"), quotes (ppr name)]
- pp_orig RecordUpdOrigin = ptext SLIT("a record update")
- pp_orig (LiteralOrigin lit) = hsep [ptext SLIT("the literal"), quotes (ppr lit)]
- pp_orig (ArithSeqOrigin seq) = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)]
- pp_orig (PArrSeqOrigin seq) = hsep [ptext SLIT("the parallel array sequence"), quotes (ppr seq)]
- pp_orig InstSigOrigin = ptext SLIT("instantiating a type signature")
- pp_orig InstScOrigin = ptext SLIT("the superclasses of an instance declaration")
- pp_orig DerivOrigin = ptext SLIT("the 'deriving' clause of a data type declaration")
- pp_orig StandAloneDerivOrigin = ptext SLIT("a 'deriving' declaration")
- pp_orig DefaultOrigin = ptext SLIT("a 'default' declaration")
- pp_orig DoOrigin = ptext SLIT("a do statement")
- pp_orig ProcOrigin = ptext SLIT("a proc expression")
- pp_orig (SigOrigin info) = pprSkolInfo info
+ | ImplicOrigin SDoc -- An implication constraint
+ | EqOrigin -- A type equality
+
+instance Outputable InstOrigin where
+ ppr (OccurrenceOf name) = hsep [ptext SLIT("a use of"), quotes (ppr name)]
+ ppr (SpecPragOrigin name) = hsep [ptext SLIT("a specialisation pragma for"), quotes (ppr name)]
+ ppr (IPOccOrigin name) = hsep [ptext SLIT("a use of implicit parameter"), quotes (ppr name)]
+ ppr (IPBindOrigin name) = hsep [ptext SLIT("a binding for implicit parameter"), quotes (ppr name)]
+ ppr RecordUpdOrigin = ptext SLIT("a record update")
+ ppr ExprSigOrigin = ptext SLIT("an expression type signature")
+ ppr ViewPatOrigin = ptext SLIT("a view pattern")
+ ppr (LiteralOrigin lit) = hsep [ptext SLIT("the literal"), quotes (ppr lit)]
+ ppr (ArithSeqOrigin seq) = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)]
+ ppr (PArrSeqOrigin seq) = hsep [ptext SLIT("the parallel array sequence"), quotes (ppr seq)]
+ ppr TupleOrigin = ptext SLIT("a tuple")
+ ppr NegateOrigin = ptext SLIT("a use of syntactic negation")
+ ppr InstScOrigin = ptext SLIT("the superclasses of an instance declaration")
+ ppr DerivOrigin = ptext SLIT("the 'deriving' clause of a data type declaration")
+ ppr StandAloneDerivOrigin = ptext SLIT("a 'deriving' declaration")
+ ppr DefaultOrigin = ptext SLIT("a 'default' declaration")
+ ppr DoOrigin = ptext SLIT("a do statement")
+ ppr ProcOrigin = ptext SLIT("a proc expression")
+ ppr (ImplicOrigin doc) = doc
+ ppr (SigOrigin info) = pprSkolInfo info
+ ppr EqOrigin = ptext SLIT("a type equality")
\end{code}