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| author | simonpj@microsoft.com <unknown> | 2010-12-02 12:35:47 +0000 |
|---|---|---|
| committer | simonpj@microsoft.com <unknown> | 2010-12-02 12:35:47 +0000 |
| commit | 5723262f616ac02ddf637f6ff480a599c737ea0d (patch) | |
| tree | 33b118dccc94a129b9b56d157b9e60a4a90242fa /compiler/hsSyn | |
| parent | fbb99e831a0c0510e79b2f0c91bbdffd142ea951 (diff) | |
| download | haskell-5723262f616ac02ddf637f6ff480a599c737ea0d.tar.gz | |
Re-jig simplifySuperClass (again)
This fixes the current loop in T3731, and will fix other
reported loops. The loops show up when we are generating
evidence for superclasses in an instance declaration.
The trick is to make the "self" dictionary simplifySuperClass
depend *explicitly* on the superclass we are currently trying
to build. See Note [Dependencies in self dictionaries] in TcSimplify.
That in turn means that EvDFunApp needs a dependency-list, used
when chasing dependencies in isGoodRecEv.
Diffstat (limited to 'compiler/hsSyn')
| -rw-r--r-- | compiler/hsSyn/HsBinds.lhs | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/compiler/hsSyn/HsBinds.lhs b/compiler/hsSyn/HsBinds.lhs index da247c28ed..0a4769dece 100644 --- a/compiler/hsSyn/HsBinds.lhs +++ b/compiler/hsSyn/HsBinds.lhs @@ -447,7 +447,10 @@ data EvTerm | EvCast EvVar Coercion -- d |> co | EvDFunApp DFunId -- Dictionary instance application - [Type] [EvVar] + [Type] [EvVar] + [EvVar] -- The dependencies, which is generally a bigger list than + -- the arguments of the dfun. + -- See Note [Dependencies in self dictionaries] in TcSimplify | EvSuperClass DictId Int -- n'th superclass. Used for both equalities and -- dictionaries, even though the former have no @@ -574,8 +577,7 @@ instance Outputable EvTerm where ppr (EvCast v co) = ppr v <+> (ptext (sLit "`cast`")) <+> pprParendType co ppr (EvCoercion co) = ppr co ppr (EvSuperClass d n) = ptext (sLit "sc") <> parens (ppr (d,n)) - ppr (EvDFunApp df tys ts) = ppr df <+> sep [ char '@' <> ppr tys - , ppr ts ] + ppr (EvDFunApp df tys ts deps) = ppr df <+> sep [ char '@' <> ppr tys, ppr ts, ppr deps ] \end{code} %************************************************************************ |