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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2015-08-05 14:24:54 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2015-08-05 16:50:41 +0100 |
| commit | 953648127cea2836ec134b03a966695ac0b36434 (patch) | |
| tree | 6b5721dc6f0133b54af97c60f396e9207ef223ae /compiler/typecheck/TcExpr.hs | |
| parent | ab98860871cfac17417d5b55e590445064d21111 (diff) | |
| download | haskell-953648127cea2836ec134b03a966695ac0b36434.tar.gz | |
Tidy up and refactor wildcard handling
When examining #10615, I found the wildcard handling hard
to understand. This patch refactors quite a bit, but with
no real change in behaviour.
* Split out TcIdSigInfo from TcSigInfo, as a separate type,
like TcPatSynInfo.
* Make TcIdSigInfo express more invariants by pushing the
wildard info into TcIdSigBndr
* Remove all special treatment of unification variables that arise
from wildcards; so the TauTv of TcType.MetaInfo loses its Bool
argument.
A ton of konck on changes. The result is significantly simpler, I think.
Diffstat (limited to 'compiler/typecheck/TcExpr.hs')
| -rw-r--r-- | compiler/typecheck/TcExpr.hs | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/compiler/typecheck/TcExpr.hs b/compiler/typecheck/TcExpr.hs index 605ba57089..d2b0c59244 100644 --- a/compiler/typecheck/TcExpr.hs +++ b/compiler/typecheck/TcExpr.hs @@ -218,9 +218,10 @@ tcExpr e@(HsLamCase _ matches) res_ty match_ctxt = MC { mc_what = CaseAlt, mc_body = tcBody } tcExpr (ExprWithTySig expr sig_ty wcs) res_ty - = do { nwc_tvs <- mapM newWildcardVarMetaKind wcs - ; tcExtendTyVarEnv nwc_tvs $ do { - sig_tc_ty <- tcHsSigType ExprSigCtxt sig_ty + = tcWildcardBinders wcs $ \ wc_prs -> + do { addErrCtxt (pprSigCtxt ExprSigCtxt empty (ppr sig_ty)) $ + emitWildcardHoleConstraints wc_prs + ; sig_tc_ty <- tcHsSigType ExprSigCtxt sig_ty ; (gen_fn, expr') <- tcGen ExprSigCtxt sig_tc_ty $ \ skol_tvs res_ty -> @@ -234,9 +235,7 @@ tcExpr (ExprWithTySig expr sig_ty wcs) res_ty ; let inner_expr = ExprWithTySigOut (mkLHsWrap gen_fn expr') sig_ty ; (inst_wrap, rho) <- deeplyInstantiate ExprSigOrigin sig_tc_ty - ; addErrCtxt (pprSigCtxt ExprSigCtxt empty (ppr sig_ty)) $ - emitWildcardHoleConstraints (zip wcs nwc_tvs) - ; tcWrapResult (mkHsWrap inst_wrap inner_expr) rho res_ty } } + ; tcWrapResult (mkHsWrap inst_wrap inner_expr) rho res_ty } tcExpr (HsType ty) _ = failWithTc (text "Can't handle type argument:" <+> ppr ty) |