Babel could create non-optimizable code

Babel transpiles default parameter value into code, that could not be optimized in V8:

 {  
   findAll(src, accumulatedItems = []) {  
     // code  
   }  
 }  

is transpiled to

 {  
   findAll: function(src) {  
     var t = this, accumulatedItems = arguments.length > 1 && void 0 !== arguments[1] ? arguments[1] : [];  
     // code  
   }  
 }  

with warning "Not optimized: Bad value context for arguments value".