[linter] Warn about reference without assignment

[exoad]

It can be troublesome if the following syntax is produced due to functions being treated as first class:

void someFunction() {

}

void main() {
 someFunction;
}

The line someFunction is referenced without being called, which can produce bugs if it was intended to be called or assigned.

There should be a linter warning to push for the programmer to either call it with .call()/() or assign it to a variable.

[FMorschel]

CC @pq

[pq]

You could catch this case, I think, with unnecessary_statements though you won't get the advice to invoke the function or assign it to a variable.

[FMorschel]

Although I don't think it would work for getters (class fields are getters) in general since they can have an impact (although they usually wouldn't) somewhere.

Could this be a request for quick fixes for the unnecessary_statements lint @exoad?

[exoad]

Although I don't think it would work for getters (class fields are getters) in general since they can have an impact (although they usually wouldn't) somewhere.

Could this be a request for quick fixes for the unnecessary_statements lint @exoad?

Oh, I guess I was not that thorough with my readings. Thank you!

If this is covered by a pre-existing rule, quick fixes would be better.