Any idea why lint or kotlin compiler is not showin...

# getting-started

[Sangeet]

Any idea why lint or kotlin compiler is not showing error for below code

fun <T : CharSequence> doSomething(): T {
    return String() as T
}

class Something(intValue: Int)

Something(doSomething()) // Doesn't show any compile error

It seems that it is automatically casting CharSequence to Number and throwing error in runtime.

[Chris Lee]

Hmm. The generic type is missing on the method invocation (this produces a compilation error Something(doSomething<String>()) ), but would expect an implicit, unchecked cast to be flagged.

[Sangeet]

Even val value: Int = doSomething() shows error. But passing that to a parameter doesn't show an error.

[Sam]

Interesting... it is a compile error under 1.3. But not 1.4+.

[Chris Lee]

…and this is a compile error: val y = doSomething(), with not enough information to infer type. Yet the same method call as a parameter compiles…

[Chris Lee]

This article is relevant: https://blog.jooq.org/the-parameterless-generic-method-antipattern/

[ephemient]

indeed, T = CharSequence & Int here, and while the are no instances of that type at runtime, that has no effect on type checking.
Note that your original code is broken in the same way for T = other subtypes of CharSequence, for example StringBuilder or javax.lang.model.element.Name