[echelon]

In some sense, taking several parameters of the same type can be a code smell.

Foo(str, str, str) strikes me as somewhat suspect. I realize this isn't always avoidable, but a lot of the time it is.

[actsasbuffoon]

There are workarounds for this kind of thing. Haskell uses newtypes to wrap a value with a semantically meaningful tag. Scala has a similar concept called "value types." That means you could turn something like this:

  loginUser(String, String)

Into this:

  loginUser(Username, Password)

These aren't just type aliases. So far as the language is concerned, Username and Password are incompatible types.