impSpecErr :: Name -> SDoc
impSpecErr name
= hang (ptext (sLit "You cannot SPECIALISE") <+> quotes (ppr name))
- 2 (ptext (sLit "because its definition has no INLINE/INLINABLE pragma"))
-
+ 2 (vcat [ ptext (sLit "because its definition has no INLINE/INLINABLE pragma")
+ , ptext (sLit "(or you compiled its definining module without -O)")])
--------------
-- If typechecking the binds fails, then return with each
-- signature-less binder given type (forall a.a), to minimise
decideGeneralisationPlan
:: DynFlags -> TopLevelFlag -> [Name] -> [LHsBind Name] -> TcSigFun -> GeneralisationPlan
decideGeneralisationPlan dflags top_lvl _bndrs binds sig_fn
+ | bang_pat_binds = NoGen
| mono_pat_binds = NoGen
| Just sig <- one_funbind_with_sig binds = if null (sig_tvs sig) && null (sig_theta sig)
then NoGen -- Optimise common case
| otherwise = InferGen mono_restriction
where
- mono_pat_binds = xopt Opt_MonoPatBinds dflags
+ bang_pat_binds = any (isBangHsBind . unLoc) binds
+ -- Bang patterns must not be polymorphic,
+ -- because we are going to force them
+ -- See Trac #4498
+
+ mono_pat_binds = xopt Opt_MonoPatBinds dflags
&& any (is_pat_bind . unLoc) binds
mono_restriction = xopt Opt_MonomorphismRestriction dflags
; checkTc (isNonRec rec_group)
(strictBindErr "Recursive" unlifted binds)
; checkTc (isSingleton binds)
- (strictBindErr "Multiple" unlifted binds)
+ (strictBindErr "Multiple" unlifted binds)
-- This should be a checkTc, not a warnTc, but as of GHC 6.11
-- the versions of alex and happy available have non-conforming
-- templates, so the GHC build fails if it's an error:
; warnUnlifted <- doptM Opt_WarnLazyUnliftedBindings
- ; warnTc (warnUnlifted && not bang_pat)
+ ; warnTc (warnUnlifted && not bang_pat && lifted_pat)
+ -- No outer bang, but it's a compound pattern
+ -- E.g (I# x#) = blah
+ -- Warn about this, but not about
+ -- x# = 4# +# 1#
+ -- (# a, b #) = ...
(unliftedMustBeBang binds) }
| otherwise
= return ()
where
- unlifted = any is_unlifted poly_ids
- bang_pat = any (isBangHsBind . unLoc) binds
+ unlifted = any is_unlifted poly_ids
+ bang_pat = any (isBangHsBind . unLoc) binds
+ lifted_pat = any (isLiftedPatBind . unLoc) binds
is_unlifted id = case tcSplitForAllTys (idType id) of
(_, rho) -> isUnLiftedType rho
unliftedMustBeBang :: [LHsBind Name] -> SDoc
unliftedMustBeBang binds
- = hang (text "Bindings containing unlifted types should use an outermost bang pattern:")
+ = hang (text "Pattern bindings containing unlifted types should use an outermost bang pattern:")
2 (pprBindList binds)
strictBindErr :: String -> Bool -> [LHsBind Name] -> SDoc