isCDictCan_Maybe, isCIPCan_Maybe, isCFunEqCan_Maybe,
isCFrozenErr,
+ WorkList, unionWorkList, unionWorkLists, isEmptyWorkList, emptyWorkList,
+ workListFromEq, workListFromNonEq,
+ workListFromEqs, workListFromNonEqs, foldrWorkListM,
+
CanonicalCt(..), Xi, tyVarsOfCanonical, tyVarsOfCanonicals, tyVarsOfCDicts,
deCanonicalise, mkFrozenError,
import HsBinds -- for TcEvBinds stuff
import Id
-
import TcRnTypes
-
import Data.IORef
+
+#ifdef DEBUG
+import StaticFlags( opt_PprStyle_Debug )
+import Control.Monad( when )
+#endif
\end{code}
isCFrozenErr :: CanonicalCt -> Bool
isCFrozenErr (CFrozenErr {}) = True
isCFrozenErr _ = False
+
+
+-- A mixture of Given, Wanted, and Derived constraints.
+-- We split between equalities and the rest to process equalities first.
+data WorkList = WorkList { weqs :: CanonicalCts
+ -- NB: weqs includes equalities /and/ family equalities
+ , wrest :: CanonicalCts }
+
+unionWorkList :: WorkList -> WorkList -> WorkList
+unionWorkList wl1 wl2
+ = WorkList { weqs = weqs wl1 `andCCan` weqs wl2
+ , wrest = wrest wl1 `andCCan` wrest wl2 }
+
+unionWorkLists :: [WorkList] -> WorkList
+unionWorkLists = foldr unionWorkList emptyWorkList
+
+isEmptyWorkList :: WorkList -> Bool
+isEmptyWorkList wl = isEmptyCCan (weqs wl) && isEmptyCCan (wrest wl)
+
+emptyWorkList :: WorkList
+emptyWorkList
+ = WorkList { weqs = emptyBag, wrest = emptyBag }
+
+workListFromEq :: CanonicalCt -> WorkList
+workListFromEq = workListFromEqs . singleCCan
+
+workListFromNonEq :: CanonicalCt -> WorkList
+workListFromNonEq = workListFromNonEqs . singleCCan
+
+workListFromNonEqs :: CanonicalCts -> WorkList
+workListFromNonEqs cts
+ = WorkList { weqs = emptyCCan, wrest = cts }
+
+workListFromEqs :: CanonicalCts -> WorkList
+workListFromEqs cts
+ = WorkList { weqs = cts, wrest = emptyCCan }
+
+foldrWorkListM :: (Monad m) => (CanonicalCt -> r -> m r)
+ -> r -> WorkList -> m r
+-- Prioritizes equalities
+foldrWorkListM on_ct r (WorkList {weqs = eqs, wrest = rest })
+ = do { r1 <- foldrBagM on_ct r eqs
+ ; foldrBagM on_ct r1 rest }
+
+instance Outputable WorkList where
+ ppr wl = vcat [ text "WorkList (Equalities) = " <+> ppr (weqs wl)
+ , text "WorkList (Other) = " <+> ppr (wrest wl) ]
+
\end{code}
+
+
%************************************************************************
%* *
CtFlavor
\begin{code}
data SimplContext
- = SimplInfer -- Inferring type of a let-bound thing
- | SimplRuleLhs -- Inferring type of a RULE lhs
- | SimplInteractive -- Inferring type at GHCi prompt
- | SimplCheck -- Checking a type signature or RULE rhs
- deriving Eq
+ = SimplInfer SDoc -- Inferring type of a let-bound thing
+ | SimplRuleLhs RuleName -- Inferring type of a RULE lhs
+ | SimplInteractive -- Inferring type at GHCi prompt
+ | SimplCheck SDoc -- Checking a type signature or RULE rhs
instance Outputable SimplContext where
- ppr SimplInfer = ptext (sLit "SimplInfer")
- ppr SimplRuleLhs = ptext (sLit "SimplRuleLhs")
+ ppr (SimplInfer d) = ptext (sLit "SimplInfer") <+> d
+ ppr (SimplCheck d) = ptext (sLit "SimplCheck") <+> d
+ ppr (SimplRuleLhs n) = ptext (sLit "SimplRuleLhs") <+> doubleQuotes (ftext n)
ppr SimplInteractive = ptext (sLit "SimplInteractive")
- ppr SimplCheck = ptext (sLit "SimplCheck")
isInteractive :: SimplContext -> Bool
isInteractive SimplInteractive = True
-- Simplify equalities only, not dictionaries
-- This is used for the LHS of rules; ee
-- Note [Simplifying RULE lhs constraints] in TcSimplify
-simplEqsOnly SimplRuleLhs = True
-simplEqsOnly _ = False
+simplEqsOnly (SimplRuleLhs {}) = True
+simplEqsOnly _ = False
performDefaulting :: SimplContext -> Bool
-performDefaulting SimplInfer = False
-performDefaulting SimplRuleLhs = False
-performDefaulting SimplInteractive = True
-performDefaulting SimplCheck = True
+performDefaulting (SimplInfer {}) = False
+performDefaulting (SimplRuleLhs {}) = False
+performDefaulting SimplInteractive = True
+performDefaulting (SimplCheck {}) = True
---------------
newtype TcS a = TcS { unTcS :: TcSEnv -> TcM a }
#ifdef DEBUG
; count <- TcM.readTcRef step_count
- ; TcM.dumpTcRn (ptext (sLit "Constraint solver steps =") <+> int count)
+ ; when (opt_PprStyle_Debug && count > 0) $
+ TcM.debugDumpTcRn (ptext (sLit "Constraint solver steps =")
+ <+> int count <+> ppr context)
#endif
-- And return
; ev_binds <- TcM.readTcRef evb_ref
ctxtUnderImplic :: SimplContext -> SimplContext
-- See Note [Simplifying RULE lhs constraints] in TcSimplify
-ctxtUnderImplic SimplRuleLhs = SimplCheck
-ctxtUnderImplic ctxt = ctxt
+ctxtUnderImplic (SimplRuleLhs n) = SimplCheck (ptext (sLit "lhs of rule")
+ <+> doubleQuotes (ftext n))
+ctxtUnderImplic ctxt = ctxt
tryTcS :: TcS a -> TcS a
-- Like runTcS, but from within the TcS monad