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{-# OPTIONS_GHC -XOverloadedStrings #-}
module T where
import Data.String
newtype MyString = MyString String deriving (Eq, Show)
instance IsString MyString where
fromString = MyString
greet1 :: MyString -> MyString
greet1 "hello" = "world"
greet1 other = other
greet2 :: String -> String
greet2 "hello" = "world"
greet2 other = other
greet3 :: (Eq s, IsString s) => s -> s
greet3 "hello" = "world"
greet3 other = other
test = do
print $ greet1 "hello"
print $ greet2 "fool"
print $ greet3 ("foo" :: String)
print $ greet3 ("bar" :: MyString)
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