babel error

$ babel --version
5.4.7
$ cat test.js
async function foo() {

}
$ babel --optional es7.asyncFunctions test.js
/Users/msikma/Projects/pksprite/node_modules/babel-core/lib/babel/transformation/file/index.js:604
      throw err;
      ^

RangeError: test.js: Maximum call stack size exceeded
    at new Boolean (native)
    at Boolean.toString (native)
    at Type.<anonymous> (/Users/msikma/Projects/pksprite/node_modules/babel-core/node_modules/regenerator/node_modules/recast/node_modules/ast-types/lib/types.js:94:25)
    at Type.Object.defineProperties.check.value (/Users/msikma/Projects/pksprite/node_modules/babel-core/node_modules/regenerator/node_modules/recast/node_modules/ast-types/lib/types.js:37:36)
    at Field.Fp.getValue (/Users/msikma/Projects/pksprite/node_modules/babel-core/node_modules/regenerator/node_modules/recast/node_modules/ast-types/lib/types.js:251:22)
    at Object.getFieldValue (/Users/msikma/Projects/pksprite/node_modules/babel-core/node_modules/regenerator/node_modules/recast/node_modules/ast-types/lib/types.js:676:26)
    at NodePath.NPp.getValueProperty (/Users/msikma/Projects/pksprite/node_modules/babel-core/node_modules/regenerator/node_modules/recast/node_modules/ast-types/lib/node-path.js:123:18)
    at getChildPath (/Users/msikma/Projects/pksprite/node_modules/babel-core/node_modules/regenerator/node_modules/recast/node_modules/ast-types/lib/path.js:50:33)
    at NodePath.get (/Users/msikma/Projects/pksprite/node_modules/babel-core/node_modules/regenerator/node_modules/recast/node_modules/ast-types/lib/path.js:74:16)
    at visitChildren (/Users/msikma/Projects/pksprite/node_modules/babel-core/node_modules/regenerator/node_modules/recast/node_modules/ast-types/lib/path-visitor.js:240:34)