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Diffstat (limited to 'compiler/GHC/Core/Predicate.hs')
| -rw-r--r-- | compiler/GHC/Core/Predicate.hs | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/compiler/GHC/Core/Predicate.hs b/compiler/GHC/Core/Predicate.hs index 43f52b9b5c..9601a92138 100644 --- a/compiler/GHC/Core/Predicate.hs +++ b/compiler/GHC/Core/Predicate.hs @@ -24,6 +24,7 @@ module GHC.Core.Predicate ( -- Implicit parameters isIPLikePred, hasIPSuperClasses, isIPTyCon, isIPClass, + isCallStackTy, isCallStackPred, isCallStackPredTy, -- Evidence variables DictId, isEvVar, isDictId @@ -44,6 +45,7 @@ import GHC.Builtin.Names import GHC.Utils.Outputable import GHC.Utils.Misc import GHC.Utils.Panic +import GHC.Data.FastString( FastString ) -- | A predicate in the solver. The solver tries to prove Wanted predicates @@ -257,6 +259,39 @@ has_ip_super_classes rec_clss cls tys initIPRecTc :: RecTcChecker initIPRecTc = setRecTcMaxBound 1 initRecTc +-- --------------------- CallStack predicates --------------------------------- + +isCallStackPredTy :: Type -> Bool +-- True of HasCallStack, or IP "blah" CallStack +isCallStackPredTy ty + | Just (tc, tys) <- splitTyConApp_maybe ty + , Just cls <- tyConClass_maybe tc + , Just {} <- isCallStackPred cls tys + = True + | otherwise + = False + +-- | Is a 'PredType' a 'CallStack' implicit parameter? +-- +-- If so, return the name of the parameter. +isCallStackPred :: Class -> [Type] -> Maybe FastString +isCallStackPred cls tys + | [ty1, ty2] <- tys + , isIPClass cls + , isCallStackTy ty2 + = isStrLitTy ty1 + | otherwise + = Nothing + +-- | Is a type a 'CallStack'? +isCallStackTy :: Type -> Bool +isCallStackTy ty + | Just tc <- tyConAppTyCon_maybe ty + = tc `hasKey` callStackTyConKey + | otherwise + = False + + {- Note [Local implicit parameters] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The function isIPLikePred tells if this predicate, or any of its |