[Git][ghc/ghc][wip/T26682] Fix scoping errors in specialisation

Simon Peyton Jones pushed to branch wip/T26682 at Glasgow Haskell Compiler / GHC Commits: c561b7c3 by Simon Peyton Jones at 2025-12-30T15:32:00+00:00 Fix scoping errors in specialisation Using -fspecialise-aggressively in #26682 showed up a couple of subtle errors in the type-class specialiser. * dumpBindUDs failed to call `deleteCallsMentioning`, resulting in a call that mentioned a dictionary that was not in scope. This call has been missing since 2009! commit c43c981705ec33da92a9ce91eb90f2ecf00be9fe Author: Simon Peyton Jones Date: Fri Oct 23 16:15:51 2009 +0000 Fixed by re-combining `dumpBindUDs` and `dumpUDs`. * I think there was another bug involving the quantified type variables in polymorphic specialisation. In any case I refactored `specHeader` and `spec_call` so that the former looks for the extra quantified type variables rather than the latter. This is quite a worthwhile simplification: less code, easier to grok. Test case in simplCore/should_compile/T26682, brilliantly minimised by @sheaf. - - - - - 4 changed files: - compiler/GHC/Core/Opt/Specialise.hs - + testsuite/tests/simplCore/should_compile/T26682.hs - + testsuite/tests/simplCore/should_compile/T26682a.hs - testsuite/tests/simplCore/should_compile/all.T Changes: ===================================== compiler/GHC/Core/Opt/Specialise.hs ===================================== @@ -654,9 +654,7 @@ specProgram guts@(ModGuts { mg_module = this_mod -- Easiest thing is to do it all at once, as if all the top-level -- decls were mutually recursive ; let top_env = SE { se_subst = Core.mkEmptySubst $ - mkInScopeSetBndrs binds - -- mkInScopeSetList $ - -- bindersOfBinds binds + mkInScopeSetBndrs binds , se_module = this_mod , se_rules = rule_env , se_dflags = dflags } @@ -816,9 +814,12 @@ spec_imports env callers dict_binds calls go :: SpecEnv -> [CallInfoSet] -> CoreM (SpecEnv, [CoreRule], [CoreBind]) go env [] = return (env, [], []) go env (cis : other_calls) - = do { -- debugTraceMsg (text "specImport {" <+> ppr cis) + = do { +-- debugTraceMsg (text "specImport {" <+> vcat [ ppr cis +-- , text "callers" <+> ppr callers +-- , text "dict_binds" <+> ppr dict_binds ]) ; (env, rules1, spec_binds1) <- spec_import env callers dict_binds cis - ; -- debugTraceMsg (text "specImport }" <+> ppr cis) +-- ; debugTraceMsg (text "specImport }" <+> ppr cis) ; (env, rules2, spec_binds2) <- go env other_calls ; return (env, rules1 ++ rules2, spec_binds1 ++ spec_binds2) } @@ -835,13 +836,18 @@ spec_import :: SpecEnv -- Passed in so that all top-level Ids are , [CoreBind] ) -- Specialised bindings spec_import env callers dict_binds cis@(CIS fn _) | isIn "specImport" fn callers - = return (env, [], []) -- No warning. This actually happens all the time - -- when specialising a recursive function, because - -- the RHS of the specialised function contains a recursive - -- call to the original function + = do { +-- debugTraceMsg (text "specImport1-bad" <+> (ppr fn $$ text "callers" <+> ppr callers)) + ; return (env, [], []) } + -- No warning. This actually happens all the time + -- when specialising a recursive function, because + -- the RHS of the specialised function contains a recursive + -- call to the original function | null good_calls - = return (env, [], []) + = do { +-- debugTraceMsg (text "specImport1-no-good" <+> (ppr cis $$ text "dict_binds" <+> ppr dict_binds)) + ; return (env, [], []) } | Just rhs <- canSpecImport dflags fn = do { -- Get rules from the external package state @@ -890,7 +896,10 @@ spec_import env callers dict_binds cis@(CIS fn _) ; return (env, rules2 ++ rules1, final_binds) } | otherwise - = do { tryWarnMissingSpecs dflags callers fn good_calls + = do { +-- debugTraceMsg (hang (text "specImport1-missed") +-- 2 (vcat [ppr cis, text "can-spec" <+> ppr (canSpecImport dflags fn)])) + ; tryWarnMissingSpecs dflags callers fn good_calls ; return (env, [], [])} where @@ -1455,7 +1464,9 @@ specBind top_lvl env (NonRec fn rhs) do_body ; (fn4, spec_defns, body_uds1) <- specDefn env body_uds fn3 rhs - ; let (free_uds, dump_dbs, float_all) = dumpBindUDs [fn4] body_uds1 + ; let can_float_this_one = exprIsTopLevelBindable rhs (idType fn) + -- exprIsTopLevelBindable: see Note [Care with unlifted bindings] + (free_uds, dump_dbs, float_all) = dumpBindUDs can_float_this_one [fn4] body_uds1 all_free_uds = free_uds `thenUDs` rhs_uds pairs = spec_defns ++ [(fn4, rhs')] @@ -1471,10 +1482,8 @@ specBind top_lvl env (NonRec fn rhs) do_body = [mkDB $ NonRec b r | (b,r) <- pairs] ++ fromOL dump_dbs - can_float_this_one = exprIsTopLevelBindable rhs (idType fn) - -- exprIsTopLevelBindable: see Note [Care with unlifted bindings] - ; if float_all && can_float_this_one then + ; if float_all then -- Rather than discard the calls mentioning the bound variables -- we float this (dictionary) binding along with the others return ([], body', all_free_uds `snocDictBinds` final_binds) @@ -1509,7 +1518,7 @@ specBind top_lvl env (Rec pairs) do_body <- specDefns rec_env uds2 (bndrs2 `zip` rhss) ; return (bndrs3, spec_defns3 ++ spec_defns2, uds3) } - ; let (final_uds, dumped_dbs, float_all) = dumpBindUDs bndrs1 uds3 + ; let (final_uds, dumped_dbs, float_all) = dumpBindUDs True bndrs1 uds3 final_bind = recWithDumpedDicts (spec_defns3 ++ zip bndrs3 rhss') dumped_dbs @@ -1630,7 +1639,6 @@ specCalls spec_imp env existing_rules calls_for_me fn rhs dflags = se_dflags env this_mod = se_module env subst = se_subst env - in_scope = Core.substInScopeSet subst -- Figure out whether the function has an INLINE pragma -- See Note [Inline specialisations] @@ -1646,9 +1654,6 @@ specCalls spec_imp env existing_rules calls_for_me fn rhs | otherwise = inl_prag - not_in_scope :: InterestingVarFun - not_in_scope v = isLocalVar v && not (v `elemInScopeSet` in_scope) - ---------------------------------------------------------- -- Specialise to one particular call pattern spec_call :: SpecInfo -- Accumulating parameter @@ -1662,47 +1667,34 @@ specCalls spec_imp env existing_rules calls_for_me fn rhs mk_extra_dfun_arg bndr | isTyVar bndr = UnspecType | otherwise = UnspecArg - -- Find qvars, the type variables to add to the binders for the rule - -- Namely those free in `ty` that aren't in scope - -- See (MP2) in Note [Specialising polymorphic dictionaries] - ; let poly_qvars = scopedSort $ fvVarList $ specArgsFVs not_in_scope call_args - subst' = subst `Core.extendSubstInScopeList` poly_qvars - -- Maybe we should clone the poly_qvars telescope? - - -- Any free Ids will have caused the call to be dropped - ; massertPpr (all isTyCoVar poly_qvars) - (ppr fn $$ ppr all_call_args $$ ppr poly_qvars) - - ; (useful, subst'', rule_bndrs, rule_lhs_args, spec_bndrs, dx_binds, spec_args) - <- specHeader subst' rhs_bndrs all_call_args - ; let all_rule_bndrs = poly_qvars ++ rule_bndrs - env' = env { se_subst = subst'' } + ; (useful, subst', rule_bndrs, rule_lhs_args, spec_bndrs, dx_binds, spec_args) + <- specHeader subst rhs_bndrs all_call_args + ; let env' = env { se_subst = subst' } -- Check for (a) usefulness and (b) not already covered -- See (SC1) in Note [Specialisations already covered] ; let all_rules = rules_acc ++ existing_rules -- all_rules: we look both in the rules_acc (generated by this invocation -- of specCalls), and in existing_rules (passed in to specCalls) - already_covered = alreadyCovered env' all_rule_bndrs fn + already_covered = alreadyCovered env' rule_bndrs fn rule_lhs_args is_active all_rules -{- ; pprTrace "spec_call" (vcat - [ text "fun: " <+> ppr fn - , text "call info: " <+> ppr _ci - , text "useful: " <+> ppr useful - , text "already_covered:" <+> ppr already_covered - , text "poly_qvars: " <+> ppr poly_qvars - , text "useful: " <+> ppr useful - , text "all_rule_bndrs:" <+> ppr all_rule_bndrs - , text "rule_lhs_args:" <+> ppr rule_lhs_args - , text "spec_bndrs:" <+> ppr spec_bndrs - , text "dx_binds:" <+> ppr dx_binds - , text "spec_args: " <+> ppr spec_args - , text "rhs_bndrs" <+> ppr rhs_bndrs - , text "rhs_body" <+> ppr rhs_body - , text "subst''" <+> ppr subst'' ]) $ - return () --} +-- ; pprTrace "spec_call" (vcat +-- [ text "fun: " <+> ppr fn +-- , text "call info: " <+> ppr _ci +-- , text "useful: " <+> ppr useful +-- , text "already_covered:" <+> ppr already_covered +-- , text "useful: " <+> ppr useful +-- , text "rule_bndrs:" <+> ppr (sep (map (pprBndr LambdaBind) rule_bndrs)) +-- , text "rule_lhs_args:" <+> ppr rule_lhs_args +-- , text "spec_bndrs:" <+> ppr (sep (map (pprBndr LambdaBind) spec_bndrs)) +-- , text "dx_binds:" <+> ppr dx_binds +-- , text "spec_args: " <+> ppr spec_args +-- , text "rhs_bndrs" <+> ppr (sep (map (pprBndr LambdaBind) rhs_bndrs)) +-- , text "rhs_body" <+> ppr rhs_body +-- , text "subst'" <+> ppr subst' +-- ]) $ return () + ; if not useful -- No useful specialisation || already_covered -- Useful, but done already @@ -1716,23 +1708,15 @@ specCalls spec_imp env existing_rules calls_for_me fn rhs -- Run the specialiser on the specialised RHS ; (rhs_body', rhs_uds) <- specExpr env'' rhs_body -{- ; pprTrace "spec_call2" (vcat - [ text "fun:" <+> ppr fn - , text "rhs_body':" <+> ppr rhs_body' ]) $ - return () --} - -- Make the RHS of the specialised function ; let spec_rhs_bndrs = spec_bndrs ++ inner_rhs_bndrs' - (rhs_uds1, inner_dumped_dbs) = dumpUDs spec_rhs_bndrs rhs_uds - (rhs_uds2, outer_dumped_dbs) = dumpUDs poly_qvars (dx_binds `consDictBinds` rhs_uds1) - -- dx_binds comes from the arguments to the call, and so can mention - -- poly_qvars but no other local binders - spec_rhs = mkLams poly_qvars $ - wrapDictBindsE outer_dumped_dbs $ - mkLams spec_rhs_bndrs $ + (rhs_uds2, inner_dumped_dbs) = dumpUDs spec_rhs_bndrs $ + dx_binds `consDictBinds` rhs_uds + -- dx_binds comes from the arguments to the call, + -- and so can mention poly_qvars but no other local binders + spec_rhs = mkLams spec_rhs_bndrs $ wrapDictBindsE inner_dumped_dbs rhs_body' - rule_rhs_args = poly_qvars ++ spec_bndrs + rule_rhs_args = spec_bndrs -- Maybe add a void arg to the specialised function, -- to avoid unlifted bindings @@ -1787,7 +1771,7 @@ specCalls spec_imp env existing_rules calls_for_me fn rhs text "SPEC" spec_rule = mkSpecRule dflags this_mod True inl_act - herald fn all_rule_bndrs rule_lhs_args + herald fn rule_bndrs rule_lhs_args (mkVarApps (Var spec_fn) rule_rhs_args1) _rule_trace_doc = vcat [ ppr fn <+> dcolon <+> ppr fn_type @@ -1798,8 +1782,12 @@ specCalls spec_imp env existing_rules calls_for_me fn rhs , text "existing" <+> ppr existing_rules ] - ; -- pprTrace "spec_call: rule" _rule_trace_doc - return ( spec_rule : rules_acc +-- ; pprTrace "spec_call: rule" (vcat [ -- text "poly_qvars" <+> ppr poly_qvars +-- text "rule_bndrs" <+> ppr rule_bndrs +-- , text "rule_lhs_args" <+> ppr rule_lhs_args +-- , text "all_call_args" <+> ppr all_call_args +-- , ppr spec_rule ]) $ + ; return ( spec_rule : rules_acc , (spec_fn, spec_rhs1) : pairs_acc , rhs_uds2 `thenUDs` uds_acc ) } } @@ -1946,6 +1934,16 @@ floating to top level anyway; but that is hard to spot (since we don't know what the non-top-level in-scope binders are) and rare (since the binding must satisfy Note [Core let-can-float invariant] in GHC.Core). +Arguably we'd be better off if we had left that `x` in the RHS of `n`, thus + f x = let n::Natural = let x::ByteArray# = <some literal> in + NB x + in wombat @192827 (n |> co) +Now we could float `n` happily. But that's in conflict with exposing the `NB` +data constructor in the body of the `let`, so I'm leaving this unresolved. + +Another case came up in #26682, where the binding had an unlifted sum type +(# Word# | ByteArray# #), itself arising from an UNPACK pragma. Test case +T26682. Note [Specialising Calls] ~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -2593,12 +2591,22 @@ specHeader subst _ [] = pure (False, subst, [], [], [], [], []) -- 'a->T1', as well as a LHS argument for the resulting RULE and unfolding -- details. specHeader subst (bndr:bndrs) (SpecType ty : args) - = do { let subst1 = Core.extendTvSubst subst bndr ty - ; (useful, subst2, rule_bs, rule_args, spec_bs, dx, spec_args) - <- specHeader subst1 bndrs args - ; pure ( useful, subst2 - , rule_bs, Type ty : rule_args - , spec_bs, dx, Type ty : spec_args ) } + = do { -- Find free_tvs, the type variables to add to the binders for the rule + -- Namely those free in `ty` that aren't in scope + -- See (MP2) in Note [Specialising polymorphic dictionaries] + let in_scope = Core.substInScopeSet subst + not_in_scope tv = not (tv `elemInScopeSet` in_scope) + free_tvs = scopedSort $ fvVarList $ + filterFV not_in_scope $ + tyCoFVsOfType ty + subst1 = subst `Core.extendSubstInScopeList` free_tvs + + ; let subst2 = Core.extendTvSubst subst1 bndr ty + ; (useful, subst3, rule_bs, rule_args, spec_bs, dx, spec_args) + <- specHeader subst2 bndrs args + ; pure ( useful, subst3 + , free_tvs ++ rule_bs, Type ty : rule_args + , free_tvs ++ spec_bs, dx, Type ty : spec_args ) } -- Next we have a type that we don't want to specialise. We need to perform -- a substitution on it (in case the type refers to 'a'). Additionally, we need @@ -2682,7 +2690,7 @@ bindAuxiliaryDict subst orig_dict_id fresh_dict_id dict_arg -- don’t bother creating a new dict binding; just substitute | exprIsTrivial dict_arg , let subst' = Core.extendSubst subst orig_dict_id dict_arg - = -- pprTrace "bindAuxiliaryDict:trivial" (ppr orig_dict_id <+> ppr dict_id) $ + = -- pprTrace "bindAuxiliaryDict:trivial" (ppr orig_dict_id <+> ppr dict_arg) $ (subst', Nothing, dict_arg) | otherwise -- Non-trivial dictionary arg; make an auxiliary binding @@ -2978,7 +2986,8 @@ pprCallInfo fn (CI { ci_key = key }) instance Outputable CallInfo where ppr (CI { ci_key = key, ci_fvs = _fvs }) - = text "CI" <> braces (sep (map ppr key)) + = text "CI" <> braces (text "fvs" <+> ppr _fvs + $$ sep (map ppr key)) unionCalls :: CallDetails -> CallDetails -> CallDetails unionCalls c1 c2 = plusDVarEnv_C unionCallInfoSet c1 c2 @@ -3394,38 +3403,49 @@ wrapDictBindsE dbs expr ---------------------- dumpUDs :: [CoreBndr] -> UsageDetails -> (UsageDetails, OrdList DictBind) --- Used at a lambda or case binder; just dump anything mentioning the binder +-- Used at binder; just dump anything mentioning the binder dumpUDs bndrs uds@(MkUD { ud_binds = orig_dbs, ud_calls = orig_calls }) | null bndrs = (uds, nilOL) -- Common in case alternatives | otherwise = -- pprTrace "dumpUDs" (vcat - -- [ text "bndrs" <+> ppr bndrs - -- , text "uds" <+> ppr uds - -- , text "free_uds" <+> ppr free_uds - -- , text "dump-dbs" <+> ppr dump_dbs ]) $ + -- [ text "bndrs" <+> ppr bndrs + -- , text "uds" <+> ppr uds + -- , text "free_uds" <+> ppr free_uds + -- , text "dump_dbs" <+> ppr dump_dbs ]) $ (free_uds, dump_dbs) where free_uds = uds { ud_binds = free_dbs, ud_calls = free_calls } bndr_set = mkVarSet bndrs (free_dbs, dump_dbs, dump_set) = splitDictBinds orig_dbs bndr_set - free_calls = deleteCallsMentioning dump_set $ -- Drop calls mentioning bndr_set on the floor - deleteCallsFor bndrs orig_calls -- Discard calls for bndr_set; there should be - -- no calls for any of the dicts in dump_dbs -dumpBindUDs :: [CoreBndr] -> UsageDetails -> (UsageDetails, OrdList DictBind, Bool) + -- Delete calls: + -- * For any binder in `bndrs` + -- * That mention a dictionary bound in `dump_set` + -- These variables aren't in scope "above" the binding and the `dump_dbs`, + -- so no call should mention them. (See #26682.) + free_calls = deleteCallsMentioning dump_set $ + deleteCallsFor bndrs orig_calls + +dumpBindUDs :: Bool -- Main binding can float to top + -> [CoreBndr] -> UsageDetails + -> (UsageDetails, OrdList DictBind, Bool) -- Used at a let(rec) binding. --- We return a boolean indicating whether the binding itself is mentioned, --- directly or indirectly, by any of the ud_calls; in that case we want to --- float the binding itself; --- See Note [Floated dictionary bindings] -dumpBindUDs bndrs (MkUD { ud_binds = orig_dbs, ud_calls = orig_calls }) - = -- pprTrace "dumpBindUDs" (ppr bndrs $$ ppr free_uds $$ ppr dump_dbs $$ ppr float_all) $ - (free_uds, dump_dbs, float_all) +-- We return a boolean indicating whether the binding itself +-- is mentioned, directly or indirectly, by any of the ud_calls; +-- in that case we want to float the binding itself. +-- See Note [Floated dictionary bindings] +-- If the boolean is True, then the returned ud_calls can mention `bndrs`; +-- if False, then returned ud_calls must not mention `bndrs` +dumpBindUDs can_float_bind bndrs (MkUD { ud_binds = orig_dbs, ud_calls = orig_calls }) + = ( MkUD { ud_binds = free_dbs, ud_calls = free_calls2 } + , dump_dbs + , can_float_bind && calls_mention_bndrs ) where - free_uds = MkUD { ud_binds = free_dbs, ud_calls = free_calls } bndr_set = mkVarSet bndrs (free_dbs, dump_dbs, dump_set) = splitDictBinds orig_dbs bndr_set - free_calls = deleteCallsFor bndrs orig_calls - float_all = dump_set `intersectsVarSet` callDetailsFVs free_calls + free_calls1 = deleteCallsFor bndrs orig_calls + calls_mention_bndrs = dump_set `intersectsVarSet` callDetailsFVs free_calls1 + free_calls2 | can_float_bind = free_calls1 + | otherwise = deleteCallsMentioning dump_set free_calls1 callsForMe :: Id -> UsageDetails -> (UsageDetails, [CallInfo]) callsForMe fn uds@MkUD { ud_binds = orig_dbs, ud_calls = orig_calls } ===================================== testsuite/tests/simplCore/should_compile/T26682.hs ===================================== @@ -0,0 +1,105 @@ +{-# LANGUAGE Haskell2010 #-} + +{-# LANGUAGE AllowAmbiguousTypes #-} +{-# LANGUAGE BangPatterns #-} +{-# LANGUAGE DataKinds #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE StandaloneKindSignatures #-} +{-# LANGUAGE TypeApplications #-} +{-# LANGUAGE TypeFamilies #-} + +{-# OPTIONS_GHC -fspecialise-aggressively #-} + +-- This is the result of @sheaf's work in minimising +-- @mikolaj's original bug report for #26682 + +module T26682 ( tensorADOnceMnistTests2 ) where + +import Prelude + +import Data.Proxy + ( Proxy (Proxy) ) + +import GHC.TypeNats +import Data.Kind + +import T26682a + + +data Concrete2 x = Concrete2 + +instance Eq ( Concrete2 a ) where + _ == _ = error "no" + {-# OPAQUE (==) #-} + +type X :: Type -> TK +type family X a + +type instance X (target y) = y +type instance X (a, b) = TKProduct (X a) (X b) +type instance X (a, b, c) = TKProduct (TKProduct (X a) (X b)) (X c) + +tensorADOnceMnistTests2 :: Int -> Bool +tensorADOnceMnistTests2 seed0 = + withSomeSNat 999 $ \ _ -> + let seed1 = + randomValue2 + @(Concrete2 (X (ADFcnnMnist2ParametersShaped Concrete2 101 101 Double Double))) + seed0 + art = mnistTrainBench2VTOGradient3 seed1 + + gg :: Concrete2 + (TKProduct + (TKProduct + (TKProduct + (TKProduct (TKR2 2 (TKScalar Double)) (TKR2 1 (TKScalar Double))) + (TKProduct (TKR2 2 (TKScalar Double)) (TKR2 1 (TKScalar Double)))) + (TKProduct (TKR2 2 (TKScalar Double)) (TKR2 1 (TKScalar Double)))) + (TKProduct (TKR 1 Double) (TKR 1 Double))) + gg = undefined + value1 = revInterpretArtifact2 art gg + in + value1 == value1 + +mnistTrainBench2VTOGradient3 + :: Int + -> AstArtifactRev2 + (TKProduct + (XParams2 Double Double) + (TKProduct (TKR2 1 (TKScalar Double)) + (TKR2 1 (TKScalar Double)))) + (TKScalar Double) +mnistTrainBench2VTOGradient3 !_ + | Dict0 <- lemTKScalarAllNumAD2 (Proxy @Double) + = undefined + +type ADFcnnMnist2ParametersShaped + (target :: TK -> Type) (widthHidden :: Nat) (widthHidden2 :: Nat) r q = + ( ( target (TKS '[widthHidden, 784] r) + , target (TKS '[widthHidden] r) ) + , ( target (TKS '[widthHidden2, widthHidden] q) + , target (TKS '[widthHidden2] r) ) + , ( target (TKS '[10, widthHidden2] r) + , target (TKS '[10] r) ) + ) + +-- | The differentiable type of all trainable parameters of this nn. +type ADFcnnMnist2Parameters (target :: TK -> Type) r q = + ( ( target (TKR 2 r) + , target (TKR 1 r) ) + , ( target (TKR 2 q) + , target (TKR 1 r) ) + , ( target (TKR 2 r) + , target (TKR 1 r) ) + ) + +type XParams2 r q = X (ADFcnnMnist2Parameters Concrete2 r q) + +data AstArtifactRev2 x z = AstArtifactRev2 + +revInterpretArtifact2 + :: AstArtifactRev2 x z + -> Concrete2 x + -> Concrete2 z +{-# OPAQUE revInterpretArtifact2 #-} +revInterpretArtifact2 _ _ = error "no" ===================================== testsuite/tests/simplCore/should_compile/T26682a.hs ===================================== @@ -0,0 +1,109 @@ +{-# LANGUAGE Haskell2010 #-} + +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE AllowAmbiguousTypes #-} +{-# LANGUAGE BangPatterns #-} +{-# LANGUAGE DataKinds #-} +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE GADTs #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE StandaloneKindSignatures #-} +{-# LANGUAGE TypeApplications #-} +{-# LANGUAGE TypeData #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeOperators #-} +{-# LANGUAGE UndecidableSuperClasses #-} +{-# LANGUAGE UndecidableInstances #-} + +module T26682a + ( TK(..), TKR, TKS, TKX + , Dict0(..) + , randomValue2 + , lemTKScalarAllNumAD2 + ) where + +import Prelude + + +import GHC.TypeLits ( KnownNat(..), Nat, SNat ) +import Data.Kind ( Type, Constraint ) +import Data.Typeable ( Typeable ) +import Data.Proxy ( Proxy ) + +import Type.Reflection +import Data.Type.Equality + +ifDifferentiable2 :: forall r a. Typeable r + => (Num r => a) -> a -> a +{-# INLINE ifDifferentiable2 #-} +ifDifferentiable2 ra _ + | Just Refl <- testEquality (typeRep @r) (typeRep @Double) = ra +ifDifferentiable2 ra _ + | Just Refl <- testEquality (typeRep @r) (typeRep @Float) = ra +ifDifferentiable2 _ a = a + +data Dict0 c where + Dict0 :: c => Dict0 c + +type ShS2 :: [Nat] -> Type +data ShS2 ns where + Z :: ShS2 '[] + S :: {-# UNPACK #-} !( SNat n ) -> !( ShS2 ns ) -> ShS2 (n ': ns) + +type KnownShS2 :: [Nat] -> Constraint +class KnownShS2 ns where + knownShS2 :: ShS2 ns + +instance KnownShS2 '[] where + knownShS2 = Z +instance ( KnownNat n, KnownShS2 ns ) => KnownShS2 ( n ': ns ) where + knownShS2 = + case natSing @n of + !i -> + case knownShS2 @ns of + !j -> + S i j + +type RandomValue2 :: Type -> Constraint +class RandomValue2 vals where + randomValue2 :: Int -> Int + + +type IsDouble :: Type -> Constraint +type family IsDouble a where + IsDouble Double = ( () :: Constraint ) + +class ( Typeable r, IsDouble r ) => NumScalar2 r +instance ( Typeable r, IsDouble r ) => NumScalar2 r + +instance forall sh r target. (KnownShS2 sh, NumScalar2 r) + => RandomValue2 (target (TKS sh r)) where + randomValue2 g = + ifDifferentiable2 @r + ( case knownShS2 @sh of + !_ -> g ) + g + +instance (RandomValue2 (target a), RandomValue2 (target b)) + => RandomValue2 (target (TKProduct a b)) where + randomValue2 g = + let g1 = randomValue2 @(target a) g + g2 = randomValue2 @(target b) g1 + in g2 + +lemTKScalarAllNumAD2 :: Proxy r -> Dict0 ( IsDouble r ) +lemTKScalarAllNumAD2 _ = undefined +{-# OPAQUE lemTKScalarAllNumAD2 #-} + + +type data TK = + TKScalar Type + | TKR2 Nat TK + | TKS2 [Nat] TK + | TKX2 [Maybe Nat] TK + | TKProduct TK TK + +type TKR n r = TKR2 n (TKScalar r) +type TKS sh r = TKS2 sh (TKScalar r) +type TKX sh r = TKX2 sh (TKScalar r) ===================================== testsuite/tests/simplCore/should_compile/all.T ===================================== @@ -563,3 +563,4 @@ test('T26115', [grep_errmsg(r'DFun')], compile, ['-O -ddump-simpl -dsuppress-uni test('T26116', normal, compile, ['-O -ddump-rules']) test('T26117', [grep_errmsg(r'==')], compile, ['-O -ddump-simpl -dsuppress-uniques']) test('T26349', normal, compile, ['-O -ddump-rules']) +test('T26682', normal, multimod_compile, ['T26682', '-O']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c561b7c362f5f6d841fe5eb04c0cea08... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c561b7c362f5f6d841fe5eb04c0cea08... 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