'return' in idris effects

EffectReturn.idr

 module Main
 
 import Effects
 import Effect.StdIO
 
 FOO : Type -> EFFECT
 FOO t = ?FOO
 
 ------------- This works -----------
 
 baz : { [FOO ()] } Eff Bool
 baz = ?baz
 
 bazAndTell : { [FOO (), STDIO] } Eff Bool
 bazAndTell = do r <- baz
                 putStrLn (show r)
                 return r
 
 ------------- This doesnt' -----------
 
 data FooType : Bool -> Type where
   TrueType  : FooType True
   FalseType : FooType False
 
 bar : { [FOO ()] ==> {rslt} [FOO (FooType rslt)] } Eff Bool
 bar = ?bar
 
 barAndPrint : { [FOO (), STDIO] ==> {rslt} [FOO (FooType rslt), STDIO] } Eff Bool
 barAndPrint = do r <- bar
                  putStrLn (show r)
                  return r -- does not compile