From 2558ec224e78bc95bcdde8f65c9ee25cdcb509d9 Mon Sep 17 00:00:00 2001
From: lewie <unknown>
Date: Sun, 14 May 2000 07:16:50 +0000
Subject: [PATCH] [project @ 2000-05-14 07:16:50 by lewie] Wobble. Fine tuning
tcSimplifyAndCheck a bit further (wrt implicit params). The key is that a
method that doesn't constrain a local tyvar, but does has implicit params,
needs to be reduced further.
---
ghc/compiler/typecheck/Inst.lhs | 15 ++++++++++-----
ghc/compiler/typecheck/TcSimplify.lhs | 3 ++-
2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/ghc/compiler/typecheck/Inst.lhs b/ghc/compiler/typecheck/Inst.lhs
index 55a1a4f40a4e..f00e8a14185f 100644
--- a/ghc/compiler/typecheck/Inst.lhs
+++ b/ghc/compiler/typecheck/Inst.lhs
@@ -25,7 +25,8 @@ module Inst (
lookupInst, lookupSimpleInst, LookupInstResult(..),
- isDict, isClassDict, isTyVarDict, isStdClassTyVarDict, isMethodFor, notFunDep,
+ isDict, isClassDict, isMethod,
+ isTyVarDict, isStdClassTyVarDict, isMethodFor, notFunDep,
instBindingRequired, instCanBeGeneralised,
zonkInst, zonkInsts, zonkFunDeps, zonkTvFunDeps,
@@ -302,10 +303,14 @@ Predicates
\begin{code}
isDict :: Inst -> Bool
isDict (Dict _ _ _) = True
-isDict other = False
+isDict other = False
isClassDict :: Inst -> Bool
isClassDict (Dict _ (Class _ _) _) = True
-isClassDict other = False
+isClassDict other = False
+
+isMethod :: Inst -> Bool
+isMethod (Method _ _ _ _ _ _) = True
+isMethod other = False
isMethodFor :: TcIdSet -> Inst -> Bool
isMethodFor ids (Method uniq id tys _ _ loc)
@@ -574,10 +579,10 @@ pprInst (Dict u pred loc) = pprPred pred <+> show_uniq u
pprInst m@(Method u id tys theta tau loc)
= hsep [ppr id, ptext SLIT("at"),
- brackets (interppSP tys),
+ brackets (interppSP tys) {- ,
ppr theta, ppr tau,
show_uniq u,
- ppr (instToId m)]
+ ppr (instToId m) -}]
pprInst (FunDep clas fds loc)
= hsep [ppr clas, ppr fds]
diff --git a/ghc/compiler/typecheck/TcSimplify.lhs b/ghc/compiler/typecheck/TcSimplify.lhs
index 08b2211cfb5b..9eb4db8dc8d6 100644
--- a/ghc/compiler/typecheck/TcSimplify.lhs
+++ b/ghc/compiler/typecheck/TcSimplify.lhs
@@ -132,7 +132,7 @@ import TcHsSyn ( TcExpr, TcId,
import TcMonad
import Inst ( lookupInst, lookupSimpleInst, LookupInstResult(..),
tyVarsOfInst, tyVarsOfInsts,
- isDict, isClassDict, isStdClassTyVarDict,
+ isDict, isClassDict, isMethod, isStdClassTyVarDict,
isMethodFor, notFunDep,
instToId, instBindingRequired, instCanBeGeneralised,
newDictFromOld,
@@ -299,6 +299,7 @@ tcSimplifyAndCheck str local_tvs given_lie wanted_lie
try_me inst
-- Does not constrain a local tyvar
| isEmptyVarSet (tyVarsOfInst inst `intersectVarSet` local_tvs)
+ && (not (isMethod inst) || null (getIPs inst))
= Free
-- When checking against a given signature we always reduce
--
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