expect {...}.throws works only when the block returns unit

        expect {}.throws<java.lang.RuntimeException>() // this works
        expect {"blah"}.throws<java.lang.RuntimeException>() // this is red in idea
        throws<RuntimeException> {"blah"} // this works

this is a really strange problem, the kotlin compiler seems to be fine with a ()-> Unit block returning something in line 3 but in line 2 it complains

[xhanin]

I think the problem is that the compiler can’t infer a ()->Unit type for the function when expect is called, while with your third example it can infer it directly for throws.

Saying that I found another workaround:

expect<()->Unit> {"blah"}.throws<java.lang.RuntimeException>()

And yet another one:

fun expecting(subject: ()->Unit): DescribeableBuilder<()->Unit> =
        expect(subject)

expecting {"blah"}.throws<java.lang.RuntimeException>()

[christophsturm]

i submitted a youtrack issue for this https://youtrack.jetbrains.com/issue/KT-26063