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kotlinlang

```fun foo() {
	val a = ..
	val b = ..
	val c = ..
	a ?: b ?: c ?: return null

	...
}```
does this code make sense? i.e. using elvis without using the result?

it makes sense, but I am not sure if it is better to use `if` for readability tho

that only `return null` if *all* of `a`, `b`, `c` are null. if that's what you want, great.

if what you actually want is to `return null` unless all of `a`, `b`, `c` are non-null (which I believe is a more common check to make), then you should either
```val a = .. ?: return null
val b = .. ?: return null
val c = .. ?: return null```
or
```if (a == null || b == null || c == null) return null```
after which all of `a`, `b`, `c` can be smart-cast to non-null

`a ?: b ?: c ?: return null` is same as `if (a == null && b == null && c == null)`

it's to check if atleast one is not null

so, yes the question is

```if (a == null && b == null && c == null) return null```
vs
```a ?: b ?: c ?: return null```
I'm not sure about the latter, why use expression and then not use the result..

abuse?

In Kotlin, _many_ expressions have their results ignored. Take, for instance, `if (cond) doSomething() else return null`. That's an expression (even if `doSomething()` returns `Unit`) but we have no qualms about ignoring its return value. Given this, I have no problem with `a ?: return null` as a succinct alternative to `if (a == null) return null`. However, I do have a problem with `a ?: b ?: c ?: return null` because it's not immediately obvious whether it's checking for _all_ or _any_ null value. It only takes me a couple of seconds to realize which one it is, but a couple of seconds is enough to interrupt my train of thought. Furthermore, if you're checking if _any_ value is non-null, then in most cases you'd want to make use of at least one such non-null value, so why not assign that non-null value to a variable anyway? So I'd use `val firstNonNull = a ?: b ?: c ?: return null`.

I'm not sure why would I use an expression an then ignore the value, when there is if statement