diff options
Diffstat (limited to 'compiler/Language/Haskell/Syntax')
| -rw-r--r-- | compiler/Language/Haskell/Syntax/Binds.hs | 292 | ||||
| -rw-r--r-- | compiler/Language/Haskell/Syntax/Expr.hs | 3 | ||||
| -rw-r--r-- | compiler/Language/Haskell/Syntax/Extension.hs | 5 |
3 files changed, 0 insertions, 300 deletions
diff --git a/compiler/Language/Haskell/Syntax/Binds.hs b/compiler/Language/Haskell/Syntax/Binds.hs index 183fce9836..c50eb7e833 100644 --- a/compiler/Language/Haskell/Syntax/Binds.hs +++ b/compiler/Language/Haskell/Syntax/Binds.hs @@ -1,5 +1,4 @@ {-# LANGUAGE ConstraintKinds #-} -{-# LANGUAGE DeriveDataTypeable #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE ScopedTypeVariables #-} @@ -34,11 +33,8 @@ import {-# SOURCE #-} Language.Haskell.Syntax.Pat import Language.Haskell.Syntax.Extension import Language.Haskell.Syntax.Type import GHC.Types.Name.Reader(RdrName) -import GHC.Tc.Types.Evidence -import GHC.Core.Type import GHC.Types.Basic import GHC.Types.SourceText -import GHC.Types.SrcLoc as SrcLoc import GHC.Types.Tickish import GHC.Types.Var import GHC.Types.Fixity @@ -48,7 +44,6 @@ import GHC.Data.BooleanFormula (LBooleanFormula) import GHC.Utils.Outputable import GHC.Utils.Panic (pprPanic) -import Data.Data hiding ( Fixity ) import Data.Void {- @@ -245,28 +240,6 @@ data HsBindLR idL idR var_rhs :: LHsExpr idR -- ^ Located only for consistency } - -- | Abstraction Bindings - | AbsBinds { -- Binds abstraction; TRANSLATION - abs_ext :: XAbsBinds idL idR, - abs_tvs :: [TyVar], - abs_ev_vars :: [EvVar], -- ^ Includes equality constraints - - -- | AbsBinds only gets used when idL = idR after renaming, - -- but these need to be idL's for the collect... code in HsUtil - -- to have the right type - abs_exports :: [ABExport idL], - - -- | Evidence bindings - -- Why a list? See "GHC.Tc.TyCl.Instance" - -- Note [Typechecking plan for instance declarations] - abs_ev_binds :: [TcEvBinds], - - -- | Typechecked user bindings - abs_binds :: LHsBinds idL, - - abs_sig :: Bool -- See Note [The abs_sig field of AbsBinds] - } - -- | Patterns Synonym Binding | PatSynBind (XPatSynBind idL idR) @@ -281,30 +254,6 @@ data HsBindLR idL idR | XHsBindsLR !(XXHsBindsLR idL idR) - -- Consider (AbsBinds tvs ds [(ftvs, poly_f, mono_f) binds] - -- - -- Creates bindings for (polymorphic, overloaded) poly_f - -- in terms of monomorphic, non-overloaded mono_f - -- - -- Invariants: - -- 1. 'binds' binds mono_f - -- 2. ftvs is a subset of tvs - -- 3. ftvs includes all tyvars free in ds - -- - -- See Note [AbsBinds] - --- | Abstraction Bindings Export -data ABExport p - = ABE { abe_ext :: XABE p - , abe_poly :: IdP p -- ^ Any INLINE pragma is attached to this Id - , abe_mono :: IdP p - , abe_wrap :: HsWrapper -- ^ See Note [ABExport wrapper] - -- Shape: (forall abs_tvs. abs_ev_vars => abe_mono) ~ abe_poly - , abe_prags :: TcSpecPrags -- ^ SPECIALISE pragmas - } - | XABExport !(XXABExport p) - - -- | - 'GHC.Parser.Annotation.AnnKeywordId' : 'GHC.Parser.Annotation.AnnPattern', -- 'GHC.Parser.Annotation.AnnEqual','GHC.Parser.Annotation.AnnLarrow', -- 'GHC.Parser.Annotation.AnnWhere','GHC.Parser.Annotation.AnnOpen' @'{'@, @@ -322,214 +271,6 @@ data PatSynBind idL idR } | XPatSynBind !(XXPatSynBind idL idR) -{- -Note [AbsBinds] -~~~~~~~~~~~~~~~ -The AbsBinds constructor is used in the output of the type checker, to -record *typechecked* and *generalised* bindings. Specifically - - AbsBinds { abs_tvs = tvs - , abs_ev_vars = [d1,d2] - , abs_exports = [ABE { abe_poly = fp, abe_mono = fm - , abe_wrap = fwrap } - ABE { slly for g } ] - , abs_ev_binds = DBINDS - , abs_binds = BIND[fm,gm] } - -where 'BIND' binds the monomorphic Ids 'fm' and 'gm', means - - fp = fwrap [/\ tvs. \d1 d2. letrec { DBINDS ] - [ ; BIND[fm,gm] } ] - [ in fm ] - - gp = ...same again, with gm instead of fm - -The 'fwrap' is an impedance-matcher that typically does nothing; see -Note [ABExport wrapper]. - -This is a pretty bad translation, because it duplicates all the bindings. -So the desugarer tries to do a better job: - - fp = /\ [a,b] -> \ [d1,d2] -> case tp [a,b] [d1,d2] of - (fm,gm) -> fm - ..ditto for gp.. - - tp = /\ [a,b] -> \ [d1,d2] -> letrec { DBINDS; BIND } - in (fm,gm) - -In general: - - * abs_tvs are the type variables over which the binding group is - generalised - * abs_ev_var are the evidence variables (usually dictionaries) - over which the binding group is generalised - * abs_binds are the monomorphic bindings - * abs_ex_binds are the evidence bindings that wrap the abs_binds - * abs_exports connects the monomorphic Ids bound by abs_binds - with the polymorphic Ids bound by the AbsBinds itself. - -For example, consider a module M, with this top-level binding, where -there is no type signature for M.reverse, - M.reverse [] = [] - M.reverse (x:xs) = M.reverse xs ++ [x] - -In Hindley-Milner, a recursive binding is typechecked with the -*recursive* uses being *monomorphic*. So after typechecking *and* -desugaring we will get something like this - - M.reverse :: forall a. [a] -> [a] - = /\a. letrec - reverse :: [a] -> [a] = \xs -> case xs of - [] -> [] - (x:xs) -> reverse xs ++ [x] - in reverse - -Notice that 'M.reverse' is polymorphic as expected, but there is a local -definition for plain 'reverse' which is *monomorphic*. The type variable -'a' scopes over the entire letrec. - -That's after desugaring. What about after type checking but before -desugaring? That's where AbsBinds comes in. It looks like this: - - AbsBinds { abs_tvs = [a] - , abs_ev_vars = [] - , abs_exports = [ABE { abe_poly = M.reverse :: forall a. [a] -> [a], - , abe_mono = reverse :: [a] -> [a]}] - , abs_ev_binds = {} - , abs_binds = { reverse :: [a] -> [a] - = \xs -> case xs of - [] -> [] - (x:xs) -> reverse xs ++ [x] } } - -Here, - - * abs_tvs says what type variables are abstracted over the binding - group, just 'a' in this case. - * abs_binds is the *monomorphic* bindings of the group - * abs_exports describes how to get the polymorphic Id 'M.reverse' - from the monomorphic one 'reverse' - -Notice that the *original* function (the polymorphic one you thought -you were defining) appears in the abe_poly field of the -abs_exports. The bindings in abs_binds are for fresh, local, Ids with -a *monomorphic* Id. - -If there is a group of mutually recursive (see Note [Polymorphic -recursion]) functions without type signatures, we get one AbsBinds -with the monomorphic versions of the bindings in abs_binds, and one -element of abe_exports for each variable bound in the mutually -recursive group. This is true even for pattern bindings. Example: - (f,g) = (\x -> x, f) -After type checking we get - AbsBinds { abs_tvs = [a] - , abs_exports = [ ABE { abe_poly = M.f :: forall a. a -> a - , abe_mono = f :: a -> a } - , ABE { abe_poly = M.g :: forall a. a -> a - , abe_mono = g :: a -> a }] - , abs_binds = { (f,g) = (\x -> x, f) } - -Note [Polymorphic recursion] -~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Consider - Rec { f x = ...(g ef)... - - ; g :: forall a. [a] -> [a] - ; g y = ...(f eg)... } - -These bindings /are/ mutually recursive (f calls g, and g calls f). -But we can use the type signature for g to break the recursion, -like this: - - 1. Add g :: forall a. [a] -> [a] to the type environment - - 2. Typecheck the definition of f, all by itself, - including generalising it to find its most general - type, say f :: forall b. b -> b -> [b] - - 3. Extend the type environment with that type for f - - 4. Typecheck the definition of g, all by itself, - checking that it has the type claimed by its signature - -Steps 2 and 4 each generate a separate AbsBinds, so we end -up with - Rec { AbsBinds { ...for f ... } - ; AbsBinds { ...for g ... } } - -This approach allows both f and to call each other -polymorphically, even though only g has a signature. - -We get an AbsBinds that encompasses multiple source-program -bindings only when - * Each binding in the group has at least one binder that - lacks a user type signature - * The group forms a strongly connected component - - -Note [The abs_sig field of AbsBinds] -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -The abs_sig field supports a couple of special cases for bindings. -Consider - - x :: Num a => (# a, a #) - x = (# 3, 4 #) - -The general desugaring for AbsBinds would give - - x = /\a. \ ($dNum :: Num a) -> - letrec xm = (# fromInteger $dNum 3, fromInteger $dNum 4 #) in - xm - -But that has an illegal let-binding for an unboxed tuple. In this -case we'd prefer to generate the (more direct) - - x = /\ a. \ ($dNum :: Num a) -> - (# fromInteger $dNum 3, fromInteger $dNum 4 #) - -A similar thing happens with representation-polymorphic defns -(#11405): - - undef :: forall (r :: RuntimeRep) (a :: TYPE r). HasCallStack => a - undef = error "undef" - -Again, the vanilla desugaring gives a local let-binding for a -representation-polymorphic (undefm :: a), which is illegal. But -again we can desugar without a let: - - undef = /\ a. \ (d:HasCallStack) -> error a d "undef" - -The abs_sig field supports this direct desugaring, with no local -let-binding. When abs_sig = True - - * the abs_binds is single FunBind - - * the abs_exports is a singleton - - * we have a complete type sig for binder - and hence the abs_binds is non-recursive - (it binds the mono_id but refers to the poly_id - -These properties are exploited in GHC.HsToCore.Binds.dsAbsBinds to -generate code without a let-binding. - -Note [ABExport wrapper] -~~~~~~~~~~~~~~~~~~~~~~~ -Consider - (f,g) = (\x.x, \y.y) -This ultimately desugars to something like this: - tup :: forall a b. (a->a, b->b) - tup = /\a b. (\x:a.x, \y:b.y) - f :: forall a. a -> a - f = /\a. case tup a Any of - (fm::a->a,gm:Any->Any) -> fm - ...similarly for g... - -The abe_wrap field deals with impedance-matching between - (/\a b. case tup a b of { (f,g) -> f }) -and the thing we really want, which may have fewer type -variables. The action happens in GHC.Tc.Gen.Bind.mkExport. --} - {- ************************************************************************ @@ -742,39 +483,6 @@ type LFixitySig pass = XRec pass (FixitySig pass) data FixitySig pass = FixitySig (XFixitySig pass) [LIdP pass] Fixity | XFixitySig !(XXFixitySig pass) --- | Type checker Specialisation Pragmas --- --- 'TcSpecPrags' conveys @SPECIALISE@ pragmas from the type checker to the desugarer -data TcSpecPrags - = IsDefaultMethod -- ^ Super-specialised: a default method should - -- be macro-expanded at every call site - | SpecPrags [LTcSpecPrag] - deriving Data - --- | Located Type checker Specification Pragmas -type LTcSpecPrag = Located TcSpecPrag - --- | Type checker Specification Pragma -data TcSpecPrag - = SpecPrag - Id - HsWrapper - InlinePragma - -- ^ The Id to be specialised, a wrapper that specialises the - -- polymorphic function, and inlining spec for the specialised function - deriving Data - -noSpecPrags :: TcSpecPrags -noSpecPrags = SpecPrags [] - -hasSpecPrags :: TcSpecPrags -> Bool -hasSpecPrags (SpecPrags ps) = not (null ps) -hasSpecPrags IsDefaultMethod = False - -isDefaultMethod :: TcSpecPrags -> Bool -isDefaultMethod IsDefaultMethod = True -isDefaultMethod (SpecPrags {}) = False - isFixityLSig :: forall p. UnXRec p => LSig p -> Bool isFixityLSig (unXRec @p -> FixSig {}) = True isFixityLSig _ = False diff --git a/compiler/Language/Haskell/Syntax/Expr.hs b/compiler/Language/Haskell/Syntax/Expr.hs index 0abd64d0d8..92cf9d5f20 100644 --- a/compiler/Language/Haskell/Syntax/Expr.hs +++ b/compiler/Language/Haskell/Syntax/Expr.hs @@ -1616,9 +1616,6 @@ data HsSplicedThing id | HsSplicedPat (Pat id) -- ^ Haskell Spliced Pattern --- See Note [Pending Splices] -type SplicePointName = Name - data UntypedSpliceFlavour = UntypedExpSplice | UntypedPatSplice diff --git a/compiler/Language/Haskell/Syntax/Extension.hs b/compiler/Language/Haskell/Syntax/Extension.hs index 6a33787d87..862c212c90 100644 --- a/compiler/Language/Haskell/Syntax/Extension.hs +++ b/compiler/Language/Haskell/Syntax/Extension.hs @@ -191,14 +191,9 @@ type family XXValBindsLR x x' type family XFunBind x x' type family XPatBind x x' type family XVarBind x x' -type family XAbsBinds x x' type family XPatSynBind x x' type family XXHsBindsLR x x' --- ABExport type families -type family XABE x -type family XXABExport x - -- PatSynBind type families type family XPSB x x' type family XXPatSynBind x x' |