-%
+
+% (c) The University of Glasgow 2006
% (c) The GRASP Project, Glasgow University, 1992-2002
%
\begin{code}
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,
- ThLevel, impLevel, topLevel,
+ ThStage(..), topStage, topAnnStage, topSpliceStage,
+ ThLevel, impLevel, outerLevel, thLevel,
-- Arrows
ArrowCtxt(NoArrowCtxt), newArrowScope, escapeArrowScope,
-- Insts
- Inst(..), InstOrigin(..), InstLoc(..), pprInstLoc,
- instLocSrcLoc, instLocSrcSpan,
- LIE, emptyLIE, unitLIE, plusLIE, consLIE,
+ Inst(..), EqInstCo, InstOrigin(..), InstLoc(..),
+ pprInstLoc, pprInstArising, instLocSpan, instLocOrigin, setInstLoc,
+ LIE, emptyLIE, unitLIE, plusLIE, consLIE, instLoc, instSpan,
plusLIEs, mkLIE, isEmptyLIE, lieToList, listToLIE,
-- Misc other types
- TcId, TcIdSet, TcDictBinds
+ TcId, TcIdSet, TcDictBinds, TcTyVarBind(..), TcTyVarBinds
+
) where
#include "HsVersions.h"
-import HsSyn ( PendingSplice, HsOverLit, LRuleDecl, LForeignDecl,
- ArithSeqInfo, DictBinds, LHsBinds, LImportDecl, HsGroup,
- ExprCoFn, IE )
-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, TvSubst,
- TcPredType, TcKind, tcCmpPred, tcCmpType, tcCmpTypes, pprSkolInfo )
-import InstEnv ( Instance, InstEnv )
+import HsSyn hiding (LIE)
+import HscTypes
+import Type
+import Coercion
+import TcType
+import Annotations
+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 UniqFM ( UniqFM )
-import UniqSupply ( UniqSupply )
-import BasicTypes ( IPName )
-import Util ( thenCmp )
+import LazyUniqFM
+import SrcLoc
+import VarSet
+import ErrUtils
+import UniqSupply
+import BasicTypes
+import Util
import Bag
import Outputable
-import Maybe ( mapMaybe )
-import ListSetOps ( unionLists )
+import ListSetOps
+import FastString
+
+import Data.Set (Set)
\end{code}
type TcM a = TcRn a -- Historical
\end{code}
+Representation of type bindings to uninstantiated meta variables used during
+constraint solving.
+
+\begin{code}
+data TcTyVarBind = TcTyVarBind TcTyVar TcType
+
+type TcTyVarBinds = Bag TcTyVarBind
+
+instance Outputable TcTyVarBind where
+ ppr (TcTyVarBind tv ty) = ppr tv <+> text ":=" <+> ppr ty
+\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
data TcGblEnv
= TcGblEnv {
- tcg_mod :: Module, -- Module being compiled
- tcg_src :: HscSource, -- What kind of module
- -- (regular Haskell, hs-boot, ext-core)
-
- tcg_rdr_env :: GlobalRdrEnv, -- Top level envt; used during renaming
- tcg_default :: Maybe [Type], -- Types used for defaulting
- -- Nothing => no 'default' decl
-
- tcg_fix_env :: FixityEnv, -- 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,
- -- along with their derived constructors, selectors.
- --
- -- (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_mod :: Module, -- ^ Module being compiled
+ tcg_src :: HscSource,
+ -- ^ What kind of module (regular Haskell, hs-boot, ext-core)
+
+ tcg_rdr_env :: GlobalRdrEnv, -- ^ Top level envt; used during renaming
+ tcg_default :: Maybe [Type],
+ -- ^ Types used for defaulting. @Nothing@ => no @default@ decl
+
+ 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,
+ -- along with their derived constructors, selectors.
+ --
+ -- (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,
-- 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
-- Updated at intervals (e.g. after dealing with types and classes)
- tcg_inst_env :: InstEnv, -- Instance envt for *home-package* modules
- -- Includes the dfuns in tcg_insts
+ tcg_inst_env :: InstEnv,
+ -- ^ Instance envt for /home-package/ modules; Includes the dfuns in
+ -- tcg_insts
+ tcg_fam_inst_env :: FamInstEnv, -- ^ Ditto for family instances
+
-- Now a bunch of things about this module that are simply
-- accumulated, but never consulted until the end.
-- Nevertheless, it's convenient to accumulate them along
-- with the rest of the info from this module.
- tcg_exports :: NameSet, -- What is exported
- tcg_imports :: ImportAvails, -- Information about what was imported
- -- from where, including things bound
- -- in this module
-
- tcg_dus :: DefUses, -- What is defined in this module and what is used.
- -- The latter is used to generate
- -- (a) version tracking; no need to recompile if these
- -- things have not changed version stamp
- -- (b) unused-import info
-
- tcg_keep :: TcRef NameSet, -- Locally-defined top-level names to keep alive
- -- "Keep alive" means give them an Exported flag, so
- -- that the simplifier does not discard them as dead
- -- code, and so that they are exposed in the interface file
- -- (but not to export to the user).
- --
- -- Some things, like dict-fun Ids and default-method Ids are
- -- "born" with the Exported flag on, for exactly the above reason,
- -- but some we only discover as we go. Specifically:
- -- * The to/from functions for generic data types
- -- * Top-level variables appearing free in the RHS of an orphan rule
- -- * Top-level variables appearing free in a TH bracket
-
- tcg_inst_uses :: TcRef NameSet, -- Home-package Dfuns actually used
- -- Used to generate version dependencies
- -- This records usages, rather like tcg_dus, but it has to
- -- be a mutable variable so it can be augmented
- -- when we look up an instance. These uses of dfuns are
- -- rather like the free variables of the program, but
- -- are implicit instead of explicit.
-
- tcg_th_used :: TcRef Bool, -- True <=> Template Haskell syntax used
- -- We need this so that we can generate a dependency on the
- -- Template Haskell package, becuase the desugarer is going to
- -- emit loads of references to TH symbols. It's rather like
- -- tcg_inst_uses; the reference is implicit rather than explicit,
- -- so we have to zap a mutable variable.
-
- tcg_dfun_n :: TcRef Int, -- Allows us to number off the names of DFuns
- -- It's convenient to allocate an External Name for a DFun, with
- -- a permanently-fixed unique, just like other top-level functions
- -- defined in this module. But that means we need a canonical
- -- occurrence name, distinct from all other dfuns in this module,
- -- and this name supply serves that purpose (df1, df2, etc).
-
- -- The next fields accumulate the payload of the module
- -- The binds, rules and foreign-decl fiels are collected
- -- initially in un-zonked form and are finally zonked in tcRnSrcDecls
-
- -- The next fields accumulate the payload of the
- -- module The binds, rules and foreign-decl fiels are
- -- collected initially in un-zonked form and are
- -- finally zonked in tcRnSrcDecls
-
- tcg_rn_imports :: Maybe [LImportDecl Name],
+ tcg_exports :: [AvailInfo], -- ^ What is exported
+ tcg_imports :: ImportAvails,
+ -- ^ Information about what was imported from where, including
+ -- things bound in this module.
+
+ tcg_dus :: DefUses,
+ -- ^ What is defined in this module and what is used.
+ -- The latter is used to generate
+ --
+ -- (a) version tracking; no need to recompile if these things have
+ -- not changed version stamp
+ --
+ -- (b) unused-import info
+
+ tcg_keep :: TcRef NameSet,
+ -- ^ Locally-defined top-level names to keep alive.
+ --
+ -- "Keep alive" means give them an Exported flag, so that the
+ -- simplifier does not discard them as dead code, and so that they
+ -- are exposed in the interface file (but not to export to the
+ -- user).
+ --
+ -- Some things, like dict-fun Ids and default-method Ids are "born"
+ -- with the Exported flag on, for exactly the above reason, but some
+ -- we only discover as we go. Specifically:
+ --
+ -- * The to/from functions for generic data types
+ --
+ -- * Top-level variables appearing free in the RHS of an orphan
+ -- rule
+ --
+ -- * Top-level variables appearing free in a TH bracket
+
+ tcg_inst_uses :: TcRef NameSet,
+ -- ^ Home-package Dfuns actually used.
+ --
+ -- Used to generate version dependencies This records usages, rather
+ -- like tcg_dus, but it has to be a mutable variable so it can be
+ -- augmented when we look up an instance. These uses of dfuns are
+ -- rather like the free variables of the program, but are implicit
+ -- instead of explicit.
+
+ tcg_th_used :: TcRef Bool,
+ -- ^ @True@ <=> Template Haskell syntax used.
+ --
+ -- We need this so that we can generate a dependency on the Template
+ -- Haskell package, becuase the desugarer is going to emit loads of
+ -- references to TH symbols. It's rather like tcg_inst_uses; the
+ -- reference is implicit rather than explicit, so we have to zap a
+ -- mutable variable.
+
+ tcg_dfun_n :: TcRef OccSet,
+ -- ^ Allows us to choose unique DFun names.
+
+ -- The next fields accumulate the payload of the module
+ -- The binds, rules and foreign-decl fiels are collected
+ -- initially in un-zonked form and are finally zonked in tcRnSrcDecls
+
tcg_rn_exports :: Maybe [Located (IE Name)],
- tcg_rn_decls :: Maybe (HsGroup Name), -- renamed decls, maybe
- -- Nothing <=> Don't retain renamed decls
-
- tcg_binds :: LHsBinds Id, -- Value bindings in this module
- tcg_deprecs :: Deprecations, -- ...Deprecations
- tcg_insts :: [Instance], -- ...Instances
- tcg_rules :: [LRuleDecl Id], -- ...Rules
- tcg_fords :: [LForeignDecl Id] -- ...Foreign import & exports
+ tcg_rn_imports :: [LImportDecl Name],
+ -- Keep the renamed imports regardless. They are not
+ -- voluminous and are needed if you want to report unused imports
+ tcg_used_rdrnames :: TcRef (Set RdrName),
+ tcg_rn_decls :: Maybe (HsGroup Name),
+ -- ^ Renamed decls, maybe. @Nothing@ <=> Don't retain renamed
+ -- decls.
+
+ tcg_binds :: LHsBinds Id, -- Value bindings in this module
+ tcg_warns :: Warnings, -- ...Warnings and deprecations
+ tcg_anns :: [Annotation], -- ...Annotations
+ tcg_insts :: [Instance], -- ...Instances
+ tcg_fam_insts :: [FamInst], -- ...Family instances
+ tcg_rules :: [LRuleDecl Id], -- ...Rules
+ tcg_fords :: [LForeignDecl Id], -- ...Foreign import & exports
+
+ tcg_doc_hdr :: Maybe LHsDocString, -- ^ Maybe Haddock header docs
+ tcg_hpc :: AnyHpcUsage, -- ^ @True@ if any part of the
+ -- prog uses hpc instrumentation.
+
+ tcg_main :: Maybe Name -- ^ The Name of the main
+ -- function, if this module is
+ -- the main module.
}
+
+data RecFieldEnv
+ = RecFields (NameEnv [Name]) -- Maps a constructor name *in this module*
+ -- to the fields for that constructor
+ NameSet -- Set of all fields declared *in this module*;
+ -- used to suppress name-shadowing complaints
+ -- when using record wild cards
+ -- E.g. let fld = e in C {..}
+ -- This is used when dealing with ".." notation in record
+ -- construction and pattern matching.
+ -- The FieldEnv deals *only* with constructors defined in *this*
+ -- module. For imported modules, we get the same info from the
+ -- TypeEnv
\end{code}
%************************************************************************
-- Discarded after typecheck/rename; not passed on to desugarer
= TcLclEnv {
tcl_loc :: SrcSpan, -- Source span
- tcl_ctxt :: ErrCtxt, -- Error context
+ tcl_ctxt :: [ErrCtxt], -- Error context, innermost on top
tcl_errs :: TcRef Messages, -- Place to accumulate errors
- tcl_th_ctxt :: ThStage, -- Template Haskell context
- tcl_arrow_ctxt :: ArrowCtxt, -- Arrow-notation context
+ tcl_th_ctxt :: ThStage, -- Template Haskell context
+ tcl_arrow_ctxt :: ArrowCtxt, -- Arrow-notation context
tcl_rdr :: LocalRdrEnv, -- Local name envt
-- Maintained during renaming, of course, but also during
-- We still need the unsullied global name env so that
-- we can look up record field names
- tcl_env :: NameEnv TcTyThing, -- The local type environment: Ids and TyVars
- -- defined in this module
+ tcl_env :: NameEnv TcTyThing, -- The local type environment: Ids and
+ -- TyVars defined in this module
tcl_tyvars :: TcRef TcTyVarSet, -- The "global tyvars"
-- Namely, the in-scope TyVars bound in tcl_env,
- -- plus the tyvars mentioned in the types of Ids bound in tcl_lenv
- -- Why mutable? see notes with tcGetGlobalTyVars
+ -- plus the tyvars mentioned in the types of Ids bound
+ -- in tcl_lenv.
+ -- Why mutable? see notes with tcGetGlobalTyVars
+
+ tcl_lie :: TcRef LIE, -- Place to accumulate type constraints
- tcl_lie :: TcRef LIE -- Place to accumulate type constraints
+ tcl_tybinds :: TcRef TcTyVarBinds -- Meta and coercion type variable
+ -- bindings accumulated during
+ -- constraint solving
}
-}
---------------------------
--- Template Haskell levels
+-- Template Haskell stages and levels
---------------------------
+data ThStage -- See Note [Template Haskell state diagram] in TcSplice
+ = Splice -- Top-level splicing
+ -- This code will be run *at compile time*;
+ -- the result replaces the splice
+ -- Binding level = 0
+
+ | Comp -- Ordinary Haskell code
+ -- Binding level = 1
+
+ | Brack -- Inside brackets
+ ThStage -- Binding level = level(stage) + 1
+ (TcRef [PendingSplice]) -- Accumulate pending splices here
+ (TcRef LIE) -- and type constraints here
+
+topStage, topAnnStage, topSpliceStage :: ThStage
+topStage = Comp
+topAnnStage = Splice
+topSpliceStage = Splice
+
+instance Outputable ThStage where
+ ppr Splice = text "Splice"
+ ppr Comp = text "Comp"
+ ppr (Brack s _ _) = text "Brack" <> parens (ppr s)
+
type ThLevel = Int
- -- Indicates how many levels of brackets we are inside
- -- (always >= 0)
+ -- See Note [Template Haskell levels] in TcSplice
-- 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
+impLevel, outerLevel :: ThLevel
impLevel = 0 -- Imported things; they can be used inside a top level splice
+outerLevel = 1 -- Things defined outside brackets
+-- NB: Things at level 0 are not *necessarily* imported.
+-- eg $( \b -> ... ) here b is bound at level 0
--
-- For example:
-- f = ...
-- g1 = $(map ...) is OK
-- g2 = $(f ...) is not OK; because we havn't compiled f yet
-
-data ThStage
- = Comp -- Ordinary compiling, at level topLevel
- | Splice ThLevel -- Inside a splice
- | Brack ThLevel -- Inside brackets;
- (TcRef [PendingSplice]) -- accumulate pending splices here
- (TcRef LIE) -- and type constraints here
-topStage, topSpliceStage :: ThStage
-topStage = Comp
-topSpliceStage = Splice (topLevel - 1) -- Stage for the body of a top-level splice
+thLevel :: ThStage -> ThLevel
+thLevel Splice = 0
+thLevel Comp = 1
+thLevel (Brack s _ _) = thLevel s + 1
---------------------------
-- Arrow-notation context
| ATcId { -- Ids defined in this module; may not be fully zonked
tct_id :: TcId,
- tct_co :: Maybe ExprCoFn, -- 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 :: TcTyThing -> SDoc
pprTcTyThingCategory (AGlobal thing) = pprTyThingCategory thing
-pprTcTyThingCategory (ATyVar {}) = ptext SLIT("Type variable")
-pprTcTyThingCategory (ATcId {}) = ptext SLIT("Local identifier")
-pprTcTyThingCategory (AThing {}) = ptext SLIT("Kinded thing")
+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}
-type ErrCtxt = [TidyEnv -> TcM (TidyEnv, Message)]
- -- Innermost first. Monadic so that we have a chance
- -- to deal with bound type variables just before error
- -- message construction
+type ErrCtxt = (Bool, TidyEnv -> TcM (TidyEnv, Message))
+ -- Monadic so that we have a chance
+ -- to deal with bound type variables just before error
+ -- message construction
+
+ -- Bool: True <=> this is a landmark context; do not
+ -- discard it when trimming for display
\end{code}
%* *
%************************************************************************
-ImportAvails summarises what was imported from where, irrespective
-of whether the imported things are actually used or not
-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
- * when figuring out what things are really unused
-
\begin{code}
+-- | 'ImportAvails' summarises what was imported from where, irrespective of
+-- whether the imported things are actually used or not. It is used:
+--
+-- * when processing the export list,
+--
+-- * when constructing usage info for the interface file,
+--
+-- * to identify the list of directly imported modules for initialisation
+-- purposes and for optimised overlap checking of family instances,
+--
+-- * when figuring out what things are really unused
+--
data ImportAvails
= ImportAvails {
- imp_env :: ModuleNameEnv NameSet,
- -- All the things imported, 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.
- --
- -- We need to classify them like this so that we can figure out
- -- "module M" export specifiers in an export list
- -- (see 1.4 Report Section 5.1.1). Ultimately, we want to find
- -- everything that is unambiguously in scope as 'M.x'
- -- and where plain 'x' is (perhaps ambiguously) in scope.
- -- So the starting point is all things that are in scope as 'M.x',
- -- which is what this field tells us.
-
- imp_mods :: ModuleEnv (Module, Bool, SrcSpan),
- -- Domain is all directly-imported modules
- -- Bool means:
- -- True => import was "import Foo ()"
- -- False => import was some other form
- --
- -- We need the Module in the range because we can't get
- -- the keys of a ModuleEnv
- -- Used
- -- (a) to help construct the usage information in
- -- the interface file; if we import somethign we
- -- need to recompile if the export version changes
- -- (b) to specify what child modules to initialise
+ imp_mods :: ModuleEnv [(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@.
+ --
+ -- The 'Bool' means:
+ --
+ -- - @True@ => import was @import Foo ()@
+ --
+ -- - @False@ => import was some other form
+ --
+ -- Used
+ --
+ -- (a) to help construct the usage information in the interface
+ -- file; if we import somethign we need to recompile if the
+ -- export version changes
+ --
+ -- (b) to specify what child modules to initialise
+ --
+ -- We need a full ModuleEnv rather than a ModuleNameEnv here,
+ -- because we might be importing modules of the same name from
+ -- different packages. (currently not the case, but might be in the
+ -- future).
imp_dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface),
- -- Home-package modules needed by the module being compiled
- --
- -- It doesn't matter whether any of these dependencies
- -- are actually *used* when compiling the module; they
- -- are listed if they are below it at all. For
- -- example, suppose M imports A which imports X. Then
- -- compiling M might not need to consult X.hi, but X
- -- is still listed in M's dependencies.
+ -- ^ Home-package modules needed by the module being compiled
+ --
+ -- It doesn't matter whether any of these dependencies
+ -- are actually /used/ when compiling the module; they
+ -- are listed if they are below it at all. For
+ -- example, suppose M imports A which imports X. Then
+ -- compiling M might not need to consult X.hi, but X
+ -- is still listed in M's dependencies.
imp_dep_pkgs :: [PackageId],
- -- Packages needed by the module being compiled, whether
- -- directly, or via other modules in this package, or via
- -- modules imported from other packages.
+ -- ^ Packages needed by the module being compiled, whether directly,
+ -- or via other modules in this package, or via modules imported
+ -- from other packages.
- imp_orphs :: [Module]
- -- Orphan modules below us in the import tree
+ imp_orphs :: [Module],
+ -- ^ Orphan modules below us in the import tree (and maybe including
+ -- us for imported modules)
+
+ 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_orphs = [],
+ imp_finsts = [] }
plusImportAvails :: ImportAvails -> ImportAvails -> ImportAvails
plusImportAvails
- (ImportAvails { imp_env = env1, imp_mods = mods1,
- imp_dep_mods = dmods1, imp_dep_pkgs = dpkgs1, imp_orphs = orphs1 })
- (ImportAvails { imp_env = env2, imp_mods = mods2,
- imp_dep_mods = dmods2, imp_dep_pkgs = dpkgs2, imp_orphs = orphs2 })
- = ImportAvails { imp_env = plusUFM_C unionNameSets env1 env2,
- imp_mods = mods1 `plusModuleEnv` mods2,
+ (ImportAvails { imp_mods = mods1,
+ imp_dep_mods = dmods1, imp_dep_pkgs = dpkgs1,
+ imp_orphs = orphs1, imp_finsts = finsts1 })
+ (ImportAvails { imp_mods = mods2,
+ imp_dep_mods = dmods2, imp_dep_pkgs = dpkgs2,
+ imp_orphs = orphs2, imp_finsts = finsts2 })
+ = ImportAvails { imp_mods = plusModuleEnv_C (++) mods1 mods2,
imp_dep_mods = plusUFM_C plus_mod_dep dmods1 dmods2,
imp_dep_pkgs = dpkgs1 `unionLists` dpkgs2,
- imp_orphs = orphs1 `unionLists` orphs2 }
+ imp_orphs = orphs1 `unionLists` orphs2,
+ imp_finsts = finsts1 `unionLists` finsts2 }
where
plus_mod_dep (m1, boot1) (m2, boot2)
= WARN( not (m1 == m2), (ppr m1 <+> ppr m2) $$ (ppr boot1 <+> ppr boot2) )
%************************************************************************
%* *
- 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}
%* *
%************************************************************************
| ImportBySystem -- Non user import.
instance Outputable WhereFrom where
- ppr (ImportByUser is_boot) | is_boot = ptext SLIT("{- SOURCE -}")
+ ppr (ImportByUser is_boot) | is_boot = ptext (sLit "{- SOURCE -}")
| otherwise = empty
- ppr ImportBySystem = ptext SLIT("{- SYSTEM -}")
+ ppr ImportBySystem = ptext (sLit "{- SYSTEM -}")
\end{code}
Method 34 doubleId [Int] origin
+In addition to the basic Haskell variants of 'Inst's, they can now also
+represent implication constraints 'forall tvs. 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, -- Class or implicit parameter only
+ tci_loc :: InstLoc
+ }
- InstLoc
+ | ImplicInst { -- An implication constraint
+ -- forall tvs. given => wanted
+ tci_name :: Name,
+ tci_tyvars :: [TcTyVar], -- Quantified type variables
+ tci_given :: [Inst], -- Only Dicts and EqInsts
+ -- (no Methods, LitInsts, ImplicInsts)
+ tci_wanted :: [Inst], -- Only Dicts, EqInst, and ImplicInsts
+ -- (no Methods or LitInsts)
- -- INVARIANT 1: in (Method u f tys theta tau loc)
- -- type of (f tys dicts(from theta)) = tau
+ tci_loc :: InstLoc
+ }
+ -- NB: the tci_given are not necessarily rigid
+
+ | 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.
- -- INVARIANT 2: tau must not be of form (Pred -> Tau)
+ tci_theta :: TcThetaType,
+ -- The (types of the) dictionaries to which the function
+ -- must be applied to get the method
+
+ 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: 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 :: EqInstCo, -- co
+ 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.
+ }
+
+type EqInstCo = Either -- Distinguish between given and wanted coercions
+ 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.
\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
- compare = cmpInst
+ compare = cmpInst
+ -- Used *only* for AvailEnv in TcSimplify
instance Eq Inst where
(==) i1 i2 = case i1 `cmpInst` i2 of
- 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)
+ EQ -> True
+ _ -> False
+
+cmpInst :: Inst -> Inst -> Ordering
+cmpInst d1@(Dict {}) d2@(Dict {}) = tci_pred d1 `tcCmpPred` tci_pred d2
+cmpInst (Dict {}) _ = 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 {}) _ = 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 {}) _ = 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 {}) _ = 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_left i1 `tcCmpType` tci_left i2) `thenCmp`
+ (tci_right i1 `tcCmpType` tci_right i2)
\end{code}
-- FIXME: Rename this. It clashes with (Located (IE ...))
type LIE = Bag Inst
-isEmptyLIE = isEmptyBag
-emptyLIE = emptyBag
-unitLIE inst = unitBag inst
-mkLIE insts = listToBag insts
+isEmptyLIE :: LIE -> Bool
+isEmptyLIE = isEmptyBag
+
+emptyLIE :: LIE
+emptyLIE = emptyBag
+
+unitLIE :: Inst -> LIE
+unitLIE inst = unitBag inst
+
+mkLIE :: [Inst] -> LIE
+mkLIE insts = listToBag insts
+
+plusLIE :: LIE -> LIE -> LIE
plusLIE lie1 lie2 = lie1 `unionBags` lie2
-consLIE inst lie = inst `consBag` lie
-plusLIEs lies = unionManyBags lies
-lieToList = bagToList
-listToLIE = listToBag
+
+plusLIEs :: [LIE] -> LIE
+plusLIEs lies = unionManyBags lies
+
+lieToList :: LIE -> [Inst]
+lieToList = bagToList
+
+listToLIE :: [Inst] -> LIE
+listToLIE = listToBag
+
+consLIE :: Inst -> LIE -> LIE
+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
+-------------------------------------------
+data InstLoc = InstLoc InstOrigin SrcSpan [ErrCtxt]
+
+instLoc :: Inst -> InstLoc
+instLoc inst = tci_loc inst
-instLocSrcLoc :: InstLoc -> SrcLoc
-instLocSrcLoc (InstLoc _ src_span _) = srcSpanStart src_span
+setInstLoc :: Inst -> InstLoc -> Inst
+setInstLoc inst new_loc = inst { tci_loc = new_loc }
-instLocSrcSpan :: InstLoc -> SrcSpan
-instLocSrcSpan (InstLoc _ src_span _) = src_span
+instSpan :: Inst -> SrcSpan
+instSpan wanted = instLocSpan (instLoc wanted)
+instLocSpan :: InstLoc -> SrcSpan
+instLocSpan (InstLoc _ s _) = s
+
+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
+
+ | NoScOrigin -- A very special hack; see TcSimplify,
+ -- Note [Recursive instances and superclases]
+
+
| 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 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
+ | AnnOrigin -- An annotation
+
+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 NoScOrigin = ptext (sLit "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")
+ ppr InstSigOrigin = panic "ppr InstSigOrigin"
+ ppr AnnOrigin = ptext (sLit "an annotation")
\end{code}
projects / ghc-hetmet.git / blobdiff