[swift-evolution] try? shouldn't work on non-method-call

[Davor Jankolija]

> This is a warning right now — do you think it should be an error?
> 
> Slavas-MacBook-Pro:~ slava$ cat ttt.swift 
> func f() {}
> 
> func g() {
>  try f()
>  try? f()
> }
> 
> Slavas-MacBook-Pro:~ slava$ swiftc ttt.swift 
> ttt.swift:4:3: warning: no calls to throwing functions occur within 'try' expression
>  try f()
>  ^
> ttt.swift:5:8: warning: no calls to throwing functions occur within 'try' expression
>  try? f()
>       ^

IMHO at least, this should be an error. As a side note I do think that try should have greater precedence than as, even though this does potentially limit calls that would use only one try on a series of throwing statement that can be handled using parentheses. The benefit is that try is probably called in the vast majority of situations (that’s my experience at least) on a single throw statement and having it have higher precedance would avoid some surprises as most developers probably already assume that try wil be executed before as.

— Davor