kotlin-fork/compiler/testData/diagnostics/tests/when/withSubjectVariable/unusedWhenSubjectVariable.kt

// !LANGUAGE: +VariableDeclarationInWhenSubject
// !DIAGNOSTICS: +UNUSED_VARIABLE

fun foo(): Any = 42

fun test() {
    when (val <!UNUSED_VARIABLE!>x<!> = foo()) {
    }
}