Hi everyone :slightly_smiling_face: Does anyone kn...

# getting-started

[Joshua Hannaford]

Hi everyone 🙂 Does anyone know why in intellij IDEA there is no autocomplete for readText even after the cast in the line above?

for (frame in incoming) {
                frame as? Frame.Text ?: continue
                val receivedText = frame.readText() // No autocomplete here
                send("You said: $receivedText")
            }

I'm going through the KTOR creating web socket chat tutorial and thought it was broken because it didn't give autocomplete for readText. It would only give readBytes for a general Frame.

[Joshua Hannaford]

Interestingly, it seems like it only happens when I don't bind the result to a variable. The following code works just fine and gives autocompletion as expected.

for (frame in incoming) {
                val f = frame as? Frame.Text ?: continue
                val receivedText = f.readText()
                send("You said: $receivedText")
            }

[ephemient]

https://kotlinlang.org/docs/typecasts.html#smart-casts

Note that smart casts work only when the compiler can guarantee that the variable won't change between the check and the usage.

[ephemient]

although for (frame in should count as a local val bind, so that's strange…

[Joshua Hannaford]

That's what I was thinking 😅 But apparently using the is keyword works as expected as well

for (frame in incoming) {
                if (frame !is Frame.Text) continue
                val receivedText = frame.readText()
                send("You said: $receivedText")
            }

[Klitos Kyriacou]

I presume the Kotlin compiler recognises the smart cast in your original example, since frame.readText() is not a compilation error, but just no autocomplete. Therefore it looks like an IntelliJ bug.