-%
+
% (c) The University of Glasgow 2006
% (c) The GRASP Project, Glasgow University, 1992-2002
%
IfGblEnv(..), IfLclEnv(..),
-- Ranamer types
- ErrCtxt,
+ ErrCtxt, RecFieldEnv(..),
ImportAvails(..), emptyImportAvails, plusImportAvails,
WhereFrom(..), mkModDeps,
-- Typechecker types
- TcTyThing(..), pprTcTyThingCategory,
+ TcTyThing(..), pprTcTyThingCategory, RefinementVisibility(..),
-- Template Haskell
- ThStage(..), topStage, topSpliceStage,
+ ThStage(..), topStage, topAnnStage, topSpliceStage,
ThLevel, impLevel, topLevel,
-- Arrows
ArrowCtxt(NoArrowCtxt), newArrowScope, escapeArrowScope,
-- Insts
- Inst(..), InstOrigin(..), InstLoc(..),
- pprInstLoc, pprInstArising, instLocSpan, instLocOrigin,
+ 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 hiding (LIE)
import HscTypes
-import Packages
import Type
+import Coercion
import TcType
-import TcGadt
+import Annotations
import InstEnv
import FamInstEnv
import IOEnv
import Var
import VarEnv
import Module
-import UniqFM
+import LazyUniqFM
import SrcLoc
import VarSet
import ErrUtils
import Bag
import Outputable
import ListSetOps
+import FastString
import Data.Maybe
import Data.List
+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_fam_inst_env :: FamInstEnv, -- Ditto for family instances
+ 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 :: [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 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 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
+
tcg_rn_exports :: Maybe [Located (IE Name)],
- tcg_rn_decls :: Maybe (HsGroup Name), -- renamed decls, maybe
- -- Nothing <=> Don't retain renamed decls
+ 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_deprecs :: Deprecations, -- ...Deprecations
+ 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 :: Maybe (HsDoc Name), -- Maybe Haddock documentation
- tcg_hmi :: HaddockModInfo Name -- Haddock module information
+ tcg_doc :: Maybe (HsDoc Name), -- ^ Maybe Haddock documentation
+ tcg_hmi :: HaddockModInfo Name, -- ^ Haddock module information
+ tcg_hpc :: AnyHpcUsage -- ^ @True@ if any part of the prog uses hpc
+ -- instrumentation.
}
+
+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}
%************************************************************************
tcl_ctxt :: ErrCtxt, -- Error context
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
}
-- 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
data ThStage
- = Comp -- Ordinary compiling, at level topLevel
+ = Comp ThLevel -- Ordinary compiling, usually at level topLevel but annotations use a lower level
| 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
+topStage, topAnnStage, topSpliceStage :: ThStage
+topStage = Comp topLevel
+topAnnStage = Comp (topLevel - 1)
topSpliceStage = Splice (topLevel - 1) -- Stage for the body of a top-level splice
---------------------------
| 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 :: 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}
%* *
%************************************************************************
-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 and
- for optimsed overlap checking of family instances
- * 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_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
- --
- -- 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_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 (and maybe
- -- including us for imported modules)
+ -- ^ 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)
+ -- ^ Family instance modules below us in the import tree (and maybe
+ -- including us for imported modules)
}
mkModDeps :: [(ModuleName, IsBootInterface)]
(ImportAvails { imp_mods = mods2,
imp_dep_mods = dmods2, imp_dep_pkgs = dpkgs2,
imp_orphs = orphs2, imp_finsts = finsts2 })
- = ImportAvails { imp_mods = mods1 `plusModuleEnv` mods2,
+ = 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,
| 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 {
tci_name :: Name,
- tci_pred :: TcPredType,
+ tci_pred :: TcPredType, -- Class or implicit parameter only
tci_loc :: InstLoc
}
| ImplicInst { -- An implication constraint
- -- forall tvs. (reft, given) => wanted
+ -- forall tvs. given => wanted
tci_name :: Name,
- tci_tyvars :: [TcTyVar], -- Includes coercion variables
- -- mentioned in tci_reft
- tci_reft :: Refinement,
- tci_given :: [Inst], -- Only Dicts
+ tci_tyvars :: [TcTyVar], -- Quantified type variables
+ tci_given :: [Inst], -- Only Dicts and EqInsts
-- (no Methods, LitInsts, ImplicInsts)
- tci_wanted :: [Inst], -- Only Dicts and ImplicInsts
+ tci_wanted :: [Inst], -- Only Dicts, EqInst, and ImplicInsts
-- (no Methods or LitInsts)
+
tci_loc :: InstLoc
}
+ -- NB: the tci_given are not necessarily rigid
| Method {
tci_id :: TcId, -- The Id for the Inst
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
\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
+ EQ -> True
+ _ -> False
+cmpInst :: Inst -> Inst -> Ordering
cmpInst d1@(Dict {}) d2@(Dict {}) = tci_pred d1 `tcCmpPred` tci_pred d2
-cmpInst (Dict {}) other = LT
+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 {}) other = LT
+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 {}) other = LT
+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 {}) (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
-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
instLoc :: Inst -> InstLoc
instLoc inst = tci_loc inst
+setInstLoc :: Inst -> InstLoc -> Inst
+setInstLoc inst new_loc = inst { tci_loc = new_loc }
+
instSpan :: Inst -> SrcSpan
instSpan wanted = instLocSpan (instLoc wanted)
instLocOrigin (InstLoc o _ _) = o
pprInstArising :: Inst -> SDoc
-pprInstArising loc = ptext SLIT("arising from") <+> pprInstLoc (tci_loc loc)
+pprInstArising loc = ptext (sLit "arising from") <+> pprInstLoc (tci_loc loc)
pprInstLoc :: InstLoc -> SDoc
pprInstLoc (InstLoc orig span _) = sep [ppr orig, text "at" <+> ppr span]
-- 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
| 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 (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 (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 InstSigOrigin = ptext SLIT("instantiating a type signature")
- 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 (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