module Agda.TypeChecking.Warnings
( MonadWarning(..)
, genericWarning
, genericNonFatalError
, warning'_, warning_, warning', warning, warnings
, raiseWarningsOnUsage
, isUnsolvedWarning
, isMetaWarning
, isMetaTCWarning
, onlyShowIfUnsolved
, WhichWarnings(..), classifyWarning
, WarningsAndNonFatalErrors, tcWarnings, nonFatalErrors
, emptyWarningsAndNonFatalErrors, classifyWarnings
, runPM
) where
import Control.Monad ( forM, unless )
import Control.Monad.Except ( MonadError(..) )
import Control.Monad.Reader ( ReaderT )
import Control.Monad.State ( StateT )
import Control.Monad.Trans ( MonadTrans, lift )
import qualified Data.List as List
import qualified Data.Map as Map
import qualified Data.Set as Set
import Data.Maybe ( catMaybes )
import Data.Semigroup ( Semigroup, (<>) )
import Agda.TypeChecking.Monad.Base
import Agda.TypeChecking.Monad.Debug
import Agda.TypeChecking.Monad.Caching
import {-# SOURCE #-} Agda.TypeChecking.Pretty (MonadPretty, prettyTCM)
import {-# SOURCE #-} Agda.TypeChecking.Pretty.Call
import {-# SOURCE #-} Agda.TypeChecking.Pretty.Warning ( prettyWarning )
import {-# SOURCE #-} Agda.TypeChecking.Monad.Pure
import Agda.Syntax.Abstract.Name ( QName )
import Agda.Syntax.Common
import Agda.Syntax.Position
import Agda.Syntax.Parser
import Agda.Interaction.Options
import Agda.Interaction.Options.Warnings
import {-# SOURCE #-} Agda.Interaction.Highlighting.Generate (highlightWarning)
import Agda.Utils.CallStack ( CallStack, HasCallStack, withCallerCallStack )
import Agda.Utils.Lens
import qualified Agda.Utils.Pretty as P
import Agda.Utils.Impossible
class (MonadPretty m, MonadError TCErr m) => MonadWarning m where
addWarning :: TCWarning -> m ()
default addWarning
:: (MonadWarning n, MonadTrans t, t n ~ m)
=> TCWarning -> m ()
addWarning = n () -> m ()
n () -> t n ()
forall (m :: * -> *) a. Monad m => m a -> t m a
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift (n () -> m ()) -> (TCWarning -> n ()) -> TCWarning -> m ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. TCWarning -> n ()
forall (m :: * -> *). MonadWarning m => TCWarning -> m ()
addWarning
instance MonadWarning m => MonadWarning (ReaderT r m)
instance MonadWarning m => MonadWarning (StateT s m)
instance MonadWarning TCM where
addWarning :: TCWarning -> TCM ()
addWarning TCWarning
tcwarn = do
([TCWarning] -> f [TCWarning]) -> TCState -> f TCState
Lens' [TCWarning] TCState
stTCWarnings Lens' [TCWarning] TCState -> ([TCWarning] -> [TCWarning]) -> TCM ()
forall (m :: * -> *) a.
MonadTCState m =>
Lens' a TCState -> (a -> a) -> m ()
`modifyTCLens` Warning -> TCWarning -> [TCWarning] -> [TCWarning]
forall {a}. Eq a => Warning -> a -> [a] -> [a]
add Warning
w' TCWarning
tcwarn
TCWarning -> TCM ()
highlightWarning TCWarning
tcwarn
where
w' :: Warning
w' = TCWarning -> Warning
tcWarning TCWarning
tcwarn
add :: Warning -> a -> [a] -> [a]
add Warning
w a
tcwarn [a]
tcwarns
| Warning -> Bool
onlyOnce Warning
w Bool -> Bool -> Bool
&& a -> [a] -> Bool
forall a. Eq a => a -> [a] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
elem a
tcwarn [a]
tcwarns = [a]
tcwarns
| Bool
otherwise = a
tcwarn a -> [a] -> [a]
forall a. a -> [a] -> [a]
: [a]
tcwarns
{-# SPECIALIZE genericWarning :: P.Doc -> TCM () #-}
genericWarning :: MonadWarning m => P.Doc -> m ()
genericWarning :: forall (m :: * -> *). MonadWarning m => Doc -> m ()
genericWarning = Warning -> m ()
forall (m :: * -> *).
(HasCallStack, MonadWarning m) =>
Warning -> m ()
warning (Warning -> m ()) -> (Doc -> Warning) -> Doc -> m ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Doc -> Warning
GenericWarning
{-# SPECIALIZE genericNonFatalError :: P.Doc -> TCM () #-}
genericNonFatalError :: MonadWarning m => P.Doc -> m ()
genericNonFatalError :: forall (m :: * -> *). MonadWarning m => Doc -> m ()
genericNonFatalError = Warning -> m ()
forall (m :: * -> *).
(HasCallStack, MonadWarning m) =>
Warning -> m ()
warning (Warning -> m ()) -> (Doc -> Warning) -> Doc -> m ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Doc -> Warning
GenericNonFatalError
{-# SPECIALIZE warning'_ :: CallStack -> Warning -> TCM TCWarning #-}
warning'_ :: (MonadWarning m) => CallStack -> Warning -> m TCWarning
warning'_ :: forall (m :: * -> *).
MonadWarning m =>
CallStack -> Warning -> m TCWarning
warning'_ CallStack
loc Warning
w = do
Range' SrcFile
r <- Lens' (Range' SrcFile) TCEnv -> m (Range' SrcFile)
forall (m :: * -> *) a. MonadTCEnv m => Lens' a TCEnv -> m a
viewTC (Range' SrcFile -> f (Range' SrcFile)) -> TCEnv -> f TCEnv
Lens' (Range' SrcFile) TCEnv
eRange
Maybe (Closure Call)
c <- Lens' (Maybe (Closure Call)) TCEnv -> m (Maybe (Closure Call))
forall (m :: * -> *) a. MonadTCEnv m => Lens' a TCEnv -> m a
viewTC (Maybe (Closure Call) -> f (Maybe (Closure Call)))
-> TCEnv -> f TCEnv
Lens' (Maybe (Closure Call)) TCEnv
eCall
Bool
b <- m Bool
forall (m :: * -> *). ReadTCState m => m Bool
areWeCaching
let r' :: Range' SrcFile
r' = case Warning
w of { NicifierIssue{} -> Range' SrcFile
forall a. Range' a
NoRange ; Warning
_ -> Range' SrcFile
r }
Doc
p <- Range' SrcFile -> Maybe (Closure Call) -> m Doc -> m Doc
forall (m :: * -> *).
MonadPretty m =>
Range' SrcFile -> Maybe (Closure Call) -> m Doc -> m Doc
sayWhen Range' SrcFile
r' Maybe (Closure Call)
c (m Doc -> m Doc) -> m Doc -> m Doc
forall a b. (a -> b) -> a -> b
$ Warning -> m Doc
forall (m :: * -> *). MonadPretty m => Warning -> m Doc
prettyWarning Warning
w
TCWarning -> m TCWarning
forall a. a -> m a
forall (m :: * -> *) a. Monad m => a -> m a
return (TCWarning -> m TCWarning) -> TCWarning -> m TCWarning
forall a b. (a -> b) -> a -> b
$ CallStack -> Range' SrcFile -> Warning -> Doc -> Bool -> TCWarning
TCWarning CallStack
loc Range' SrcFile
r Warning
w Doc
p Bool
b
{-# SPECIALIZE warning_ :: Warning -> TCM TCWarning #-}
warning_ :: (HasCallStack, MonadWarning m) => Warning -> m TCWarning
warning_ :: forall (m :: * -> *).
(HasCallStack, MonadWarning m) =>
Warning -> m TCWarning
warning_ = (CallStack -> m TCWarning) -> m TCWarning
forall b. HasCallStack => (CallStack -> b) -> b
withCallerCallStack ((CallStack -> m TCWarning) -> m TCWarning)
-> (Warning -> CallStack -> m TCWarning) -> Warning -> m TCWarning
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (CallStack -> Warning -> m TCWarning)
-> Warning -> CallStack -> m TCWarning
forall a b c. (a -> b -> c) -> b -> a -> c
flip CallStack -> Warning -> m TCWarning
forall (m :: * -> *).
MonadWarning m =>
CallStack -> Warning -> m TCWarning
warning'_
{-# SPECIALIZE warnings' :: CallStack -> [Warning] -> TCM () #-}
warnings' :: MonadWarning m => CallStack -> [Warning] -> m ()
warnings' :: forall (m :: * -> *).
MonadWarning m =>
CallStack -> [Warning] -> m ()
warnings' CallStack
loc [Warning]
ws = do
WarningMode
wmode <- PragmaOptions -> WarningMode
optWarningMode (PragmaOptions -> WarningMode) -> m PragmaOptions -> m WarningMode
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> m PragmaOptions
forall (m :: * -> *). HasOptions m => m PragmaOptions
pragmaOptions
[Maybe TCWarning]
merrs <- [Warning]
-> (Warning -> m (Maybe TCWarning)) -> m [Maybe TCWarning]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
t a -> (a -> m b) -> m (t b)
forM [Warning]
ws ((Warning -> m (Maybe TCWarning)) -> m [Maybe TCWarning])
-> (Warning -> m (Maybe TCWarning)) -> m [Maybe TCWarning]
forall a b. (a -> b) -> a -> b
$ \ Warning
w' -> do
TCWarning
tcwarn <- CallStack -> Warning -> m TCWarning
forall (m :: * -> *).
MonadWarning m =>
CallStack -> Warning -> m TCWarning
warning'_ CallStack
loc Warning
w'
if WarningMode
wmode WarningMode -> Lens' Bool WarningMode -> Bool
forall o i. o -> Lens' i o -> i
^. (Bool -> f Bool) -> WarningMode -> f WarningMode
Lens' Bool WarningMode
warn2Error Bool -> Bool -> Bool
&& Warning -> WarningName
warningName Warning
w' WarningName -> Set WarningName -> Bool
forall a. Eq a => a -> Set a -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` WarningMode
wmode WarningMode
-> Lens' (Set WarningName) WarningMode -> Set WarningName
forall o i. o -> Lens' i o -> i
^. (Set WarningName -> f (Set WarningName))
-> WarningMode -> f WarningMode
Lens' (Set WarningName) WarningMode
warningSet
then Maybe TCWarning -> m (Maybe TCWarning)
forall a. a -> m a
forall (f :: * -> *) a. Applicative f => a -> f a
pure (TCWarning -> Maybe TCWarning
forall a. a -> Maybe a
Just TCWarning
tcwarn)
else Maybe TCWarning
forall a. Maybe a
Nothing Maybe TCWarning -> m () -> m (Maybe TCWarning)
forall a b. a -> m b -> m a
forall (f :: * -> *) a b. Functor f => a -> f b -> f a
<$ TCWarning -> m ()
forall (m :: * -> *). MonadWarning m => TCWarning -> m ()
addWarning TCWarning
tcwarn
let errs :: [TCWarning]
errs = [Maybe TCWarning] -> [TCWarning]
forall a. [Maybe a] -> [a]
catMaybes [Maybe TCWarning]
merrs
Bool -> m () -> m ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
unless ([TCWarning] -> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [TCWarning]
errs) (m () -> m ()) -> m () -> m ()
forall a b. (a -> b) -> a -> b
$ CallStack -> TypeError -> m ()
forall (m :: * -> *) a.
MonadTCError m =>
CallStack -> TypeError -> m a
typeError' CallStack
loc (TypeError -> m ()) -> TypeError -> m ()
forall a b. (a -> b) -> a -> b
$ [TCWarning] -> TypeError
NonFatalErrors [TCWarning]
errs
{-# SPECIALIZE warnings :: HasCallStack => [Warning] -> TCM () #-}
warnings :: (HasCallStack, MonadWarning m) => [Warning] -> m ()
warnings :: forall (m :: * -> *).
(HasCallStack, MonadWarning m) =>
[Warning] -> m ()
warnings = (CallStack -> m ()) -> m ()
forall b. HasCallStack => (CallStack -> b) -> b
withCallerCallStack ((CallStack -> m ()) -> m ())
-> ([Warning] -> CallStack -> m ()) -> [Warning] -> m ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (CallStack -> [Warning] -> m ()) -> [Warning] -> CallStack -> m ()
forall a b c. (a -> b -> c) -> b -> a -> c
flip CallStack -> [Warning] -> m ()
forall (m :: * -> *).
MonadWarning m =>
CallStack -> [Warning] -> m ()
warnings'
{-# SPECIALIZE warning' :: CallStack -> Warning -> TCM () #-}
warning' :: MonadWarning m => CallStack -> Warning -> m ()
warning' :: forall (m :: * -> *).
MonadWarning m =>
CallStack -> Warning -> m ()
warning' CallStack
loc = CallStack -> [Warning] -> m ()
forall (m :: * -> *).
MonadWarning m =>
CallStack -> [Warning] -> m ()
warnings' CallStack
loc ([Warning] -> m ()) -> (Warning -> [Warning]) -> Warning -> m ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Warning -> [Warning]
forall a. a -> [a]
forall (f :: * -> *) a. Applicative f => a -> f a
pure
{-# SPECIALIZE warning :: HasCallStack => Warning -> TCM () #-}
warning :: (HasCallStack, MonadWarning m) => Warning -> m ()
warning :: forall (m :: * -> *).
(HasCallStack, MonadWarning m) =>
Warning -> m ()
warning = (CallStack -> m ()) -> m ()
forall b. HasCallStack => (CallStack -> b) -> b
withCallerCallStack ((CallStack -> m ()) -> m ())
-> (Warning -> CallStack -> m ()) -> Warning -> m ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (CallStack -> Warning -> m ()) -> Warning -> CallStack -> m ()
forall a b c. (a -> b -> c) -> b -> a -> c
flip CallStack -> Warning -> m ()
forall (m :: * -> *).
MonadWarning m =>
CallStack -> Warning -> m ()
warning'
{-# SPECIALIZE raiseWarningsOnUsage :: QName -> TCM () #-}
raiseWarningsOnUsage :: (MonadWarning m, ReadTCState m) => QName -> m ()
raiseWarningsOnUsage :: forall (m :: * -> *).
(MonadWarning m, ReadTCState m) =>
QName -> m ()
raiseWarningsOnUsage QName
d = do
[Char] -> VerboseLevel -> [Char] -> m ()
forall (m :: * -> *).
MonadDebug m =>
[Char] -> VerboseLevel -> [Char] -> m ()
reportSLn [Char]
"scope.warning.usage" VerboseLevel
50 ([Char] -> m ()) -> [Char] -> m ()
forall a b. (a -> b) -> a -> b
$ [Char]
"Checking usage of " [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ QName -> [Char]
forall a. Pretty a => a -> [Char]
P.prettyShow QName
d
(Text -> m ()) -> Maybe Text -> m ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (Warning -> m ()
forall (m :: * -> *).
(HasCallStack, MonadWarning m) =>
Warning -> m ()
warning (Warning -> m ()) -> (Text -> Warning) -> Text -> m ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Text -> Warning
UserWarning) (Maybe Text -> m ()) -> m (Maybe Text) -> m ()
forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< QName -> Map QName Text -> Maybe Text
forall k a. Ord k => k -> Map k a -> Maybe a
Map.lookup QName
d (Map QName Text -> Maybe Text)
-> m (Map QName Text) -> m (Maybe Text)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> m (Map QName Text)
forall (m :: * -> *). ReadTCState m => m (Map QName Text)
getUserWarnings
isUnsolvedWarning :: Warning -> Bool
isUnsolvedWarning :: Warning -> Bool
isUnsolvedWarning Warning
w = Warning -> WarningName
warningName Warning
w WarningName -> Set WarningName -> Bool
forall a. Ord a => a -> Set a -> Bool
`Set.member` Set WarningName
unsolvedWarnings
isMetaWarning :: Warning -> Bool
isMetaWarning :: Warning -> Bool
isMetaWarning = \case
UnsolvedInteractionMetas{} -> Bool
True
UnsolvedMetaVariables{} -> Bool
True
Warning
_ -> Bool
False
isMetaTCWarning :: TCWarning -> Bool
isMetaTCWarning :: TCWarning -> Bool
isMetaTCWarning = Warning -> Bool
isMetaWarning (Warning -> Bool) -> (TCWarning -> Warning) -> TCWarning -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. TCWarning -> Warning
tcWarning
onlyOnce :: Warning -> Bool
onlyOnce :: Warning -> Bool
onlyOnce InversionDepthReached{} = Bool
True
onlyOnce Warning
_ = Bool
False
onlyShowIfUnsolved :: Warning -> Bool
onlyShowIfUnsolved :: Warning -> Bool
onlyShowIfUnsolved InversionDepthReached{} = Bool
True
onlyShowIfUnsolved Warning
_ = Bool
False
data WhichWarnings =
ErrorWarnings
| AllWarnings
deriving (WhichWarnings -> WhichWarnings -> Bool
(WhichWarnings -> WhichWarnings -> Bool)
-> (WhichWarnings -> WhichWarnings -> Bool) -> Eq WhichWarnings
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
$c== :: WhichWarnings -> WhichWarnings -> Bool
== :: WhichWarnings -> WhichWarnings -> Bool
$c/= :: WhichWarnings -> WhichWarnings -> Bool
/= :: WhichWarnings -> WhichWarnings -> Bool
Eq, Eq WhichWarnings
Eq WhichWarnings
-> (WhichWarnings -> WhichWarnings -> Ordering)
-> (WhichWarnings -> WhichWarnings -> Bool)
-> (WhichWarnings -> WhichWarnings -> Bool)
-> (WhichWarnings -> WhichWarnings -> Bool)
-> (WhichWarnings -> WhichWarnings -> Bool)
-> (WhichWarnings -> WhichWarnings -> WhichWarnings)
-> (WhichWarnings -> WhichWarnings -> WhichWarnings)
-> Ord WhichWarnings
WhichWarnings -> WhichWarnings -> Bool
WhichWarnings -> WhichWarnings -> Ordering
WhichWarnings -> WhichWarnings -> WhichWarnings
forall a.
Eq a
-> (a -> a -> Ordering)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> a)
-> (a -> a -> a)
-> Ord a
$ccompare :: WhichWarnings -> WhichWarnings -> Ordering
compare :: WhichWarnings -> WhichWarnings -> Ordering
$c< :: WhichWarnings -> WhichWarnings -> Bool
< :: WhichWarnings -> WhichWarnings -> Bool
$c<= :: WhichWarnings -> WhichWarnings -> Bool
<= :: WhichWarnings -> WhichWarnings -> Bool
$c> :: WhichWarnings -> WhichWarnings -> Bool
> :: WhichWarnings -> WhichWarnings -> Bool
$c>= :: WhichWarnings -> WhichWarnings -> Bool
>= :: WhichWarnings -> WhichWarnings -> Bool
$cmax :: WhichWarnings -> WhichWarnings -> WhichWarnings
max :: WhichWarnings -> WhichWarnings -> WhichWarnings
$cmin :: WhichWarnings -> WhichWarnings -> WhichWarnings
min :: WhichWarnings -> WhichWarnings -> WhichWarnings
Ord)
classifyWarning :: Warning -> WhichWarnings
classifyWarning :: Warning -> WhichWarnings
classifyWarning Warning
w =
if Warning -> WarningName
warningName Warning
w WarningName -> Set WarningName -> Bool
forall a. Ord a => a -> Set a -> Bool
`Set.member` Set WarningName
errorWarnings
then WhichWarnings
ErrorWarnings
else WhichWarnings
AllWarnings
data WarningsAndNonFatalErrors = WarningsAndNonFatalErrors
{ WarningsAndNonFatalErrors -> [TCWarning]
tcWarnings :: [TCWarning]
, WarningsAndNonFatalErrors -> [TCWarning]
nonFatalErrors :: [TCWarning]
}
emptyWarningsAndNonFatalErrors :: WarningsAndNonFatalErrors
emptyWarningsAndNonFatalErrors :: WarningsAndNonFatalErrors
emptyWarningsAndNonFatalErrors = [TCWarning] -> [TCWarning] -> WarningsAndNonFatalErrors
WarningsAndNonFatalErrors [] []
classifyWarnings :: [TCWarning] -> WarningsAndNonFatalErrors
classifyWarnings :: [TCWarning] -> WarningsAndNonFatalErrors
classifyWarnings [TCWarning]
ws = [TCWarning] -> [TCWarning] -> WarningsAndNonFatalErrors
WarningsAndNonFatalErrors [TCWarning]
warnings [TCWarning]
errors
where
partite :: TCWarning -> Bool
partite = (WhichWarnings -> WhichWarnings -> Bool
forall a. Ord a => a -> a -> Bool
< WhichWarnings
AllWarnings) (WhichWarnings -> Bool)
-> (TCWarning -> WhichWarnings) -> TCWarning -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Warning -> WhichWarnings
classifyWarning (Warning -> WhichWarnings)
-> (TCWarning -> Warning) -> TCWarning -> WhichWarnings
forall b c a. (b -> c) -> (a -> b) -> a -> c
. TCWarning -> Warning
tcWarning
([TCWarning]
errors, [TCWarning]
warnings) = (TCWarning -> Bool) -> [TCWarning] -> ([TCWarning], [TCWarning])
forall a. (a -> Bool) -> [a] -> ([a], [a])
List.partition TCWarning -> Bool
partite [TCWarning]
ws
runPM :: PM a -> TCM a
runPM :: forall a. PM a -> TCM a
runPM PM a
m = do
(Either ParseError a
res, [ParseWarning]
ws) <- PM a -> TCMT IO (Either ParseError a, [ParseWarning])
forall (m :: * -> *) a.
MonadIO m =>
PM a -> m (Either ParseError a, [ParseWarning])
runPMIO PM a
m
(ParseWarning -> TCM ()) -> [ParseWarning] -> TCM ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (Warning -> TCM ()
forall (m :: * -> *).
(HasCallStack, MonadWarning m) =>
Warning -> m ()
warning (Warning -> TCM ())
-> (ParseWarning -> Warning) -> ParseWarning -> TCM ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ParseWarning -> Warning
ParseWarning) [ParseWarning]
ws
case Either ParseError a
res of
Left ParseError
e -> TCErr -> TCM a
forall a. TCErr -> TCMT IO a
forall e (m :: * -> *) a. MonadError e m => e -> m a
throwError (Range' SrcFile -> Doc -> TCErr
Exception (ParseError -> Range' SrcFile
forall a. HasRange a => a -> Range' SrcFile
getRange ParseError
e) (ParseError -> Doc
forall a. Pretty a => a -> Doc
P.pretty ParseError
e))
Right a
a -> a -> TCM a
forall a. a -> TCMT IO a
forall (m :: * -> *) a. Monad m => a -> m a
return a
a