The short answer is yes.

To add some pedantry, I wouldn’t call it “treeshaking” per se. import is more “opening up the module” to use for function resolution, not so much “importing” it as you would think about it in JS. All imported functions are being expanding to their fully qualified names during compilation.

While :only isn’t strictly necessary, it is nice for when someone comes blind to a function in your module and it may not be obvious where a particular function is coming from if import is used multiple times. With your example of Ecto.Query, though, I never both specifying from because it’s generally super obvious by the context of the file what from is. It’s context-dependent and, of course, a matter of taste!

But ya, unused functions are not compiled.