Elvis operator (AKA Optional chaining)

[emil14]

In TS and Kotlin we can use ?. to access nullable fields on objects safely, and we can infinitely chain them

foo?.bar?.baz?.bax

We already have "error-guard" operator ? for ergonomic error handling, and there're some ideas for #746 where expressions like d[k] or l[i] return maybe (or Option, if we will go full rust-like in #751), also we have struct selectors syntax foo -> .bar -> .baz but what we don't have is ergonomic syntax for safe access to struct fields that are maybe/option if there's some nesting

type Foo struct {
  bar maybe<struct {
    baz maybe<struct{
      bax maybe<int>
    }>
  }>
}

...

foo -> ?.bar?.baz?.bax -> match {
  some -> println
  none -> panic
}