Repository : ssh://darcs.haskell.org//srv/darcs/ghc On branch : master
http://hackage.haskell.org/trac/ghc/changeset/7fa2ce2043e2faed2b2b545ba5c1c9958954800a >--------------------------------------------------------------- commit 7fa2ce2043e2faed2b2b545ba5c1c9958954800a Author: Simon Peyton Jones <simo...@microsoft.com> Date: Wed Jan 2 16:24:14 2013 +0000 Tidy the type in badInstSigErr (fixes Trac #7545) >--------------------------------------------------------------- compiler/typecheck/TcInstDcls.lhs | 18 +++++++++++++----- 1 files changed, 13 insertions(+), 5 deletions(-) diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs index 5cd54d3..610ec35 100644 --- a/compiler/typecheck/TcInstDcls.lhs +++ b/compiler/typecheck/TcInstDcls.lhs @@ -940,16 +940,24 @@ mkMethIds sig_fn clas tyvars dfun_ev_vars inst_tys sel_id do { sig_ty <- tcHsSigType (FunSigCtxt sel_name) hs_ty ; inst_sigs <- xoptM Opt_InstanceSigs ; if inst_sigs then - checkTc (sig_ty `eqType` local_meth_ty) - (badInstSigErr sel_name local_meth_ty) + unless (sig_ty `eqType` local_meth_ty) + (badInstSigErr sel_name local_meth_ty) else addErrTc (misplacedInstSig sel_name hs_ty) ; return sig_ty } -badInstSigErr :: Name -> Type -> SDoc +badInstSigErr :: Name -> Type -> TcM () badInstSigErr meth ty - = hang (ptext (sLit "Method signature does not match class; it should be")) - 2 (pprPrefixName meth <+> dcolon <+> ppr ty) + = do { env0 <- tcInitTidyEnv + ; let tidy_ty = tidyType env0 ty + -- Tidy the type using the ambient TidyEnv, + -- to avoid apparent name capture (Trac #7475) + -- class C a where { op :: a -> b } + -- instance C (a->b) where + -- op :: forall x. x + -- op = ...blah... + ; addErrTc (hang (ptext (sLit "Method signature does not match class; it should be")) + 2 (pprPrefixName meth <+> dcolon <+> ppr tidy_ty)) } misplacedInstSig :: Name -> LHsType Name -> SDoc misplacedInstSig name hs_ty _______________________________________________ Cvs-ghc mailing list Cvs-ghc@haskell.org http://www.haskell.org/mailman/listinfo/cvs-ghc
