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kotlinlang

Hey folks, question about `.let` and nullability.

Code snippet:
```val foo : String? = "sample"
foo.let { it.toUpperCase() }```
Results in:
`Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type String?`

The definition is:
```public inline fun &lt;T, R&gt; T.let(block: (T) -&gt; R): R```
So no, there's no restriction on the nullability of `T`.

The trick you can use to filter out nulls is
```foo?.let { it.toUpperCase() }```

:man-facepalming: ... the missing `?` ...

But note that this has nothing to do with `let` specifically, it works just as well for other functions.

Thanks! I appreciate that. Forgot about leading `?` and was expecting some magic. Was about to blame Kotlin version upgrade. :simple_smile:

Just remember that your code currently does nothing. toUpperCase does not modify the underlying string, but rather returns a new string with upper case.

Also, your specific example can be shortened to `foo?.toUpperCase()`. IntelliJ or Detekt should warn about unnecessary `let`