Undeclared dependency on babel-types

This package appears to work with Babel 7, which is cool; but unfortunately, I get this error out-of-the-box:

$ babel src --ignore '**/*.bs.js' --copy-files --out-dir lib
{ Error: Cannot find module 'babel-types'
    at Function.Module._resolveFilename (module.js:547:15)
    at Function.Module._load (module.js:474:25)
    at Module.require (module.js:596:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/Users/ec/Work/game-engine/node_modules/babel-plugin-bucklescript/dist/index.js:16:19)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
    at tryModuleLoad (module.js:505:12)
    at Function.Module._load (module.js:497:3) code: 'MODULE_NOT_FOUND' }

$ npm ls babel-types
game-engine@0.101.1 /Users/ec/Work/game-engine
└── (empty)

This appears to resolve itself if I explicitly install the Babel v6 version of babel-types alongside my Babel v7 modules, with npm i -D babel-types. Not a beautiful solution, though.

mike-engel / babel-plugin-bucklescript

Undeclared dependency on babel-types #7