Is it possible to make a type-alias (or something equivalent) in Scala that takes two parameters and returns their common supertype? In other words, I'm trying to find something with this signature:

type CommonSupertype[A, B] // can't be more specific

where these hold true: (pseudocode)

CommonSupertype[String, Int] = Any
CommonSupertype[JButton, JPanel] = JComponent

etc.

I haven't been able to find it myself, but I can't use alternatives like adding an extra parameter, since I have to follow a pre-specified interface.

scala types
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