[julienfr112]

it means that the fact that the monad is looping or checking for null or awaiting a future is coded in the function itself, and hidden when reading the for loop. When types are heavily overloaded, it can take minutes to know if we are looping a iterable, awaiting a futurable or checking for null a maybeable. And what about a Maybe(List) ? a Future of list ? Common, how is this not Hell ?

[igorbark]

Haskell's type inference is optional: if you felt the above code is difficult to understand, you could manually specify the type of each statement.

In a language with a less powerful type system, you could write the same information in comments, but then the compiler wouldn't warn you if you accidentally changed the side effects of a statement.