Actually `main` in Haskell can be an IO action returning any type, eg this is a perfectly valid main: main :: IO Int main = print "10" >> pure 10 the

Actually `main` in Haskell can be an IO action returning any type, eg this is a perfectly valid main: main :: IO Int main = print "10" >> pure 10 the return value is just ignored when it's actually invoked as an executable (but can be used if invoked eg. in the repl, or if main is also called from somewhere deeper in the code).