/* istanbul ignore next 
Copied from https://github.com/eslint/eslint/blob/16fad5880bb70e9dddbeab8ed0f425ae51f5841f/lib/code-path-analysis/code-path-analyzer.js#L137

@param {CodePathAnalyzer} analyzer - The instance.
@param {ASTNode} node - The current AST node.
@returns {void}
function forwardCurrentToHead(analyzer, node) {
    const codePath = analyzer.codePath
    const state = CodePath.getState(codePath)
    const currentSegments = state.currentSegments
    const headSegments = state.headSegments
    const end = Math.max(currentSegments.length, headSegments.length)
    let i = 0
    let currentSegment = null
    let headSegment = null

    // Fires leaving events.
    for (i = 0; i < end; ++i) {
        currentSegment = currentSegments[i]
        headSegment = headSegments[i]

        if (currentSegment !== headSegment && currentSegment) {
            if (currentSegment.reachable) {
                analyzer.emitter.emit(
                    "onCodePathSegmentEnd",
                    currentSegment,
                    node
                )
            }
        }
    }

    // Update state.
    state.currentSegments = headSegments

    // Fires entering events.
    for (i = 0; i < end; ++i) {
        currentSegment = currentSegments[i]
        headSegment = headSegments[i]

        if (currentSegment !== headSegment && headSegment) {
            CodePathSegment.markUsed(headSegment)
            if (headSegment.reachable) {
                analyzer.emitter.emit(
                    "onCodePathSegmentStart",
                    headSegment,
                    node
                )
            }
        }
    }
}