Completions: Tension between autocomplete on backspace and viewing function sources

[DavisVaughan]

Say I want to look at the source of slide_index_sum(), typically I:

• Type enough to let the completions figure out what I want and hit Tab to accept the completion
• Hit backspace to remove the () that get inserted
• Hit Enter to just submit slide_index_sum and see the source

#1502 has added some tension to this workflow. It is now quite hard to do this because of the very aggressive 10ms delay before completions pop up. I basically have to Esc out of the quick suggestion window

Screen.Recording.2023-10-11.at.2.53.13.PM.mov

Turning the delay up to 250ms does basically fix the problem, but I also want to note that RStudio has some smarts around this, and while it does use backspace as a "trigger" character to provide suggestions, it does not try to provide suggestions after removing the (), so this is never a problem there:

Screen.Recording.2023-10-11.at.3.01.43.PM.mov

I wonder if we can find a way to not kill the intellisense session when the user typos their way off the quick suggestion menu. Maybe that would be better than using the backspace key as a "trigger" character for a new intellisense session?

[jgutman]

Note that I also have this same issue if I want to see the help for a function. If I do ?filter, parentheses get added. Help still works if I call ?filter() instead of ?filter, but it would be nice to have the smarts not to add the parentheses after a ? as the first character (I don't know if this should be considered a separate issue)

[juliasilge]

In build 1453 this now works really nicely for viewing function source:

function-source.mov