TypeError: Cannot destructure property `startBufferRow` of 'undefined' or 'null'

Got this error when trying to view the PR pane item "Files" tab for https://github.com/apiaryio/metamorphoses/pull/88 (pulled from list here https://github.com/github/analytics/pull/454)

<img width="837" alt="pr__apiaryio_metamorphoses_88_ _chore__decaffeinate_ ___github_github" src="https://user-images.githubusercontent.com/7910250/52306243-58d06980-2965-11e9-9d8d-b46ab854085d.png">
