Inside macros, methods don't show up in completion after a dot

[xscd]

Methods do not show up inside macros. Needs some explicit letters else no methods are shown.

https://users.rust-lang.org/t/question-about-rust-analyzer-behaviour/57302

[Veykril]

The problem here is that just println!("{}", a.) can't be expanded as it doesn't match any of the macro matchers, therefor because the macro can't be expanded we cannot show completions as the a. is just random tokens.

As soon as a char gets typed though the macro can be expanded as a.b is a proper expression unlike a..

[lnicola]

Can we use the same trick of inserting a bogus identifier after dot in a macro invocation?

[Veykril]

We are doing that in general when calculating completions but the problem is that we fetch the relevant ast nodes from the original file here it seems, which in this case then don't exist. I'm not sure if we can fix this.

[flodiebold]

We do the trick and expand the macro with that input as well. The problem is that we can't resolve anything within the 'hypothetical' expansion, so to do further recursive expansion, we have to have a similar expansion in the original case (without the fake identifier) so we can check the resolution there. To fix this, we'd need to have some way of doing more deep analysis of those hypothetical ASTs.

[flodiebold]

By the way, I think actually the problem here could and needs to be fixed by better error resilience in matchers, i.e. m. should be accepted as an expr if there's no better match.