While reading a RFC for the Rust programming language, I came across this paragraph:
Given the above code, there is no way for bar to choose a return type X that could fundamentally differ between instantiations of Self -while still being instantiable with an arbitrary U.
The word instantiable caught my eye and my spell checker agreed that it wasn't a word. However, neither was the alternative I'd expected it to be: instantiatable.
Merriam-Webster defines instantiate as:
to represent (an abstraction) by a concrete instance
Which seems to match up well with the general programming concept as I understand it, so I don't believe deep programming knowledge is required to weigh-in on this formation of the English word.