KT element: KtIsExpression
FIR element: FirTypeOperatorCallImpl
FIR source kind: KtRealSourceElementKind

FIR element rendered:
(R|<local>/x| is R|kotlin/String|)

FIR FILE:
FILE: [ResolvedTo(IMPORTS)] isExpression.kt
    public final [ResolvedTo(BODY_RESOLVE)] fun foo([ResolvedTo(BODY_RESOLVE)] x: R|kotlin/Any|): R|kotlin/Boolean| {
        ^foo (R|<local>/x| is R|kotlin/String|)
    }