diff options
Diffstat (limited to 'compiler/GHC/Tc/Validity.hs')
| -rw-r--r-- | compiler/GHC/Tc/Validity.hs | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/compiler/GHC/Tc/Validity.hs b/compiler/GHC/Tc/Validity.hs index da51f7245f..59f18e5d74 100644 --- a/compiler/GHC/Tc/Validity.hs +++ b/compiler/GHC/Tc/Validity.hs @@ -66,6 +66,7 @@ import GHC.Types.Name import GHC.Types.Var.Env import GHC.Types.Var.Set import GHC.Types.Var ( VarBndr(..), isInvisibleFunArg, mkTyVar ) +import GHC.Types.SourceFile import GHC.Types.SrcLoc import GHC.Types.Unique.Set( isEmptyUniqSet ) @@ -1436,9 +1437,8 @@ We can also have instances for functions: @instance Foo (a -> b) ...@. checkValidInstHead :: UserTypeCtxt -> Class -> [Type] -> TcM () checkValidInstHead ctxt clas cls_args = do { dflags <- getDynFlags - ; is_boot <- tcIsHsBootOrSig - ; is_sig <- tcIsHsig - ; check_special_inst_head dflags is_boot is_sig ctxt clas cls_args + ; hsc_src <- tcHscSource + ; check_special_inst_head dflags hsc_src ctxt clas cls_args ; checkValidTypePats (classTyCon clas) cls_args } @@ -1468,15 +1468,15 @@ in hsig files, where `is_sig` is True. -} -check_special_inst_head :: DynFlags -> Bool -> Bool - -> UserTypeCtxt -> Class -> [Type] -> TcM () +check_special_inst_head :: DynFlags -> HscSource -> UserTypeCtxt + -> Class -> [Type] -> TcM () -- Wow! There are a surprising number of ad-hoc special cases here. -- TODO: common up the logic for special typeclasses (see GHC ticket #20441). -check_special_inst_head dflags is_boot is_sig ctxt clas cls_args +check_special_inst_head dflags hs_src ctxt clas cls_args - -- If not in an hs-boot file, abstract classes cannot have instances + -- Abstract classes cannot have instances, except in hs-boot or signature files. | isAbstractClass clas - , not is_boot + , hs_src == HsSrcFile = failWithTc (TcRnAbstractClassInst clas) -- Complain about hand-written instances of built-in classes @@ -1486,7 +1486,7 @@ check_special_inst_head dflags is_boot is_sig ctxt clas cls_args -- allow a standalone deriving declaration: they are no-ops, -- and we warn about them in GHC.Tc.Deriv.deriveStandalone. | clas_nm == typeableClassName - , not is_sig + , not (hs_src == HsigFile) -- Note [Instances of built-in classes in signature files] , hand_written_bindings = failWithTc $ TcRnSpecialClassInst clas False @@ -1495,7 +1495,7 @@ check_special_inst_head dflags is_boot is_sig ctxt clas cls_args -- are forbidden outside of signature files (#12837). -- Derived instances are forbidden completely (#21087). | clas_nm `elem` [ knownNatClassName, knownSymbolClassName, knownCharClassName ] - , (not is_sig && hand_written_bindings) || derived_instance + , (not (hs_src == HsigFile) && hand_written_bindings) || derived_instance -- Note [Instances of built-in classes in signature files] = failWithTc $ TcRnSpecialClassInst clas False |