Comment by kbp

It works the same way in Haskell, eg

  main = do
    let x = 2
    let x = "foo"
    y <- pure 3
    y <- pure "bar"
    putStrLn $ x ++ y

which is really the same as

  main =
    let x = 2
    in let x = "foo"
       in pure 3 >>= \y ->
                       pure "bar" >>= \y ->
                                        putStrLn $ x ++ y

So it works pretty naturally where each assignment is kind of like a new scope. If the type system is good, I don't think it really causes issues.