As a senior developer, I don’t find copilot particularly useful. Maybe it would have been more useful earlier in my career, but at this point writing a prompt to get copilot to regurgitate useful code and massaging the resulting output almost always takes as much or more time as it would for me just to write whatever it is I need to write. If I am able to give copilot a sufficiently specific prompt that it can ‘solve’ my problem for me, I already know how to solve the problem and how to write the code. So all I’m doing is using copilot as a ghost writer instead of writing it myself. And it doesn’t seem to be any faster. The autocomplete features are net helpful because they’re actually what I want often enough to offset the cost of reading the suggestion and deciding if it’s useful. But it’s not a huge difference (vs writing it myself) so that by itself is not sufficiently useful to justify paying the cost myself nor sufficient motivation to go to the effort of convincing my employer to pay for it.
I use chat the most. It’s pretty good once you understand the importance of building context, set up personas, and feed it workable prompts. The biggest mistake I see people do is presume that you can expect it to output gold when inputting garbage.
Once you build up an understanding of what personas work for your personal tastes and what context you need to have, it can output impressive results. The most success I’ve been having is with somewhat complex refactorizations. Stuff like “refactor X so that Y and Y” can save you a lot of time.
The most disappointing experience has been with writing unit tests. copilot has this infuriating tendency to remove old tests when you’re prompting it to add new ones. You need to explicitly request it to append tests to file X without overwriting existing tests for it not to mess up, and even then results are sketchy. For unit tests it’s also important to setup good contexts otherwise whatever time you save by prompting copilot to write them will be wasted refactoring code to use specific frameworks and follow specific styles.
I’ve run into that exact issue with copilot (deleting my tests). It is infuriating.
I don’t think I’d trust it to refactor code for me, not for anything important. I’d need to completely understand both the initial state and the result on a statement-by-statement level to be confident the result wasn’t secretly garbage and at that point I might as well write everything myself.