Scala has been called complex with its rich feature set by many of my colleagues and some even blamed all those new features of it. While most programmers are aware of the OO-features, and at least the decent ones also know about functional programming, there is one feature in particular in Scala for which I am not aware of its historical origins.

Given that a major mantra of our profession is to not reinvent the wheel, I am rather confident, that Scala does not have any actual unheard-of-before features, but I stand to be corrected on this one if necessary.

To get to the actual question, while I am aware of the origins of most of Scala's features I have never seen something like its implicit declarations before. Are there other (older!) languages out there which also provide this feature?

Does it make sense to distinguish the different cases of implicits (as they may originate from different sources), namely implict conversions and implicit parameters?