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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2019-02-25 08:31:33 +0000 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2019-03-05 03:09:41 -0500 |
| commit | 80dfcee61e3bfb67f131cd674f96467e16c0f9d8 (patch) | |
| tree | 3b486a446fa687097b66b99dc22424ec929e2aaf /compiler/deSugar/DsMeta.hs | |
| parent | e6ce17433b75c6c985bffaf1f6fc18d299666ccb (diff) | |
| download | haskell-80dfcee61e3bfb67f131cd674f96467e16c0f9d8.tar.gz | |
Be more careful when naming TyCon binders
This patch fixes two rather gnarly test cases:
* Trac #16342 (mutual recursion)
See Note [Tricky scoping in generaliseTcTyCon]
* Trac #16221 (shadowing)
See Note [Unification variables need fresh Names]
The main changes are:
* Substantial reworking of TcTyClsDecls.generaliseTcTyCon
This is the big change, and involves the rather tricky
function TcHsSyn.zonkRecTyVarBndrs.
See Note [Inferring kinds for type declarations] and
Note [Tricky scoping in generaliseTcTyCon] for the details.
* bindExplicitTKBndrs_Tv and bindImplicitTKBndrs_Tv both now
allocate /freshly-named/ unification variables. Indeed, more
generally, unification variables are always fresh; see
Note [Unification variables need fresh Names] in TcMType
* Clarify the role of tcTyConScopedTyVars.
See Note [Scoped tyvars in a TcTyCon] in TyCon
As usual, this dragged in some more refactoring:
* Renamed TcMType.zonkTyCoVarBndr to zonkAndSkolemise
* I renamed checkValidTelescope to checkTyConTelescope;
it's only used on TyCons, and indeed takes a TyCon as argument.
* I folded the slightly-mysterious reportFloatingKvs into
checkTyConTelescope. (Previously all its calls immediately
followed a call to checkTyConTelescope.) It makes much more
sense there.
* I inlined some called-once functions to simplify
checkValidTyFamEqn. It's less spaghetti-like now.
* This patch also fixes Trac #16251. I'm not quite sure why #16251
went wrong in the first place, nor how this patch fixes it, but
hey, it's good, and life is short.
Diffstat (limited to 'compiler/deSugar/DsMeta.hs')
| -rw-r--r-- | compiler/deSugar/DsMeta.hs | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/compiler/deSugar/DsMeta.hs b/compiler/deSugar/DsMeta.hs index 5e0976d1a2..67a05d647d 100644 --- a/compiler/deSugar/DsMeta.hs +++ b/compiler/deSugar/DsMeta.hs @@ -208,7 +208,7 @@ get_scoped_tvs (dL->L _ signature) | HsIB { hsib_ext = implicit_vars , hsib_body = hs_ty } <- sig , (explicit_vars, _) <- splitLHsForAllTy hs_ty - = implicit_vars ++ map hsLTyVarName explicit_vars + = implicit_vars ++ hsLTyVarNames explicit_vars get_scoped_tvs_from_sig (XHsImplicitBndrs _) = panic "get_scoped_tvs_from_sig" @@ -1037,7 +1037,7 @@ addHsTyVarBinds :: [LHsTyVarBndr GhcRn] -- the binders to be added -> (Core [TH.TyVarBndrQ] -> DsM (Core (TH.Q a))) -- action in the ext env -> DsM (Core (TH.Q a)) addHsTyVarBinds exp_tvs thing_inside - = do { fresh_exp_names <- mkGenSyms (map hsLTyVarName exp_tvs) + = do { fresh_exp_names <- mkGenSyms (hsLTyVarNames exp_tvs) ; term <- addBinds fresh_exp_names $ do { kbs <- repList tyVarBndrQTyConName mk_tv_bndr (exp_tvs `zip` fresh_exp_names) |