snake_case named function arguments cause an error in CamelCase module

[kirjs]

This when trying to run fix my js on this code: function test(fix_me){} the following error is triggered:

TypeError: Cannot read property 'type' of undefined
at Object.useCamelCase [as Identifier] (/Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/lib/rules/camelCase.js:8:39)
at /Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/lib/index.js:116:25
at Object.foldl (/Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/node_modules/fu/fu.js:135:32)
at /Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/lib/index.js:114:17
at traverse (/Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/lib/index.js:75:12)
at self (/Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/lib/index.js:65:38)
at Object.concatMap (/Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/node_modules/fu/fu.js:144:11)
at traverse (/Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/lib/index.js:70:19)
at self (/Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/lib/index.js:65:38)
at Object.concatMap (/Users/kirill.cherkashin/code/temp/test-gulp-fixmyjs/node_modules/gulp-fixmyjs/node_modules/fixmyjs/node_modules/fu/fu.js:144:11)

[goatslacker]

This is working on both master and recast branch.