/**
         * Not all expressions appear in the [ControlFlowGraph].
         * Still, if we find at least some of them, it's very unlikely that we will ever find a better graph.
         */
        val firCandidates = buildSet {
            fun addCandidate(firCandidate: FirElement) {
                add(firCandidate)

            // Type parameters, return types and other annotations are all contained in KtUserType,
            // and are never considered used as expressions
            is KtUserType ->
                false

            // Only top-level named declarations have KtFile/KtScript Parents, and are never considered used
            is KtFile ->
                false
            is KtScript ->
                false

        function: FirSimpleFunction,
        other: FirLiteralExpression<*>
    ): FirLiteralExpression<*>? {
        if (value == null || other.value == null) return null
        // NB: some utils accept very general types, and due to the way operation map works, we should up-cast rhs type.
        val rightType = when {
            function.symbol.callableId.isStringEquals -> CompileTimeType.ANY