firFunctionDeclarations.add(function)
            super.visitFunction(function)
        }

        override fun visitLoop(loop: FirLoop) {
            firLoopStatements.add(loop)
            super.visitLoop(loop)
        }

        override fun visitReturnExpression(returnExpression: FirReturnExpression) {

                parent.condition == child ||
                        ((parent.then == child ||
                                parent.`else` == child) && isUsed(parent))

            // For expressions use their loop range expression.
            is KtForExpression ->
                parent.loopRange == child

            // While, DoWhile loops use their conditions, not their bodies
            is KtWhileExpressionBase ->