kztk-m

open import Relation.Binary.PropositionalEquality
open import Data.Unit
open import Data.Product 

open ≡-Reasoning

variable 
  A : Set
  B : Set 

kztk-m

{-# LANGUAGE RecursiveDo #-}

f = do rec a <- do a <- b
                   putStrLn "Hello"
                   return a
           b <- do return $ return a :: IO (IO ())
       return a

f' = do rec b <- do return $ return a :: IO (IO ())
            a <- do a <- b

kztk-m

{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE Strict              #-}

import           Debug.Trace

h :: forall a. a -> ()
h a =
  let f :: Show a => ()
      f = trace "Hi" $ traceShow a ()
  in ()