Panic in parser.ParseFile

[mrduncan]

I came across the following panic while doing some fuzzing and figured I'd pass it along:

package main

import "github.com/dop251/goja/parser"

func main() {
	parser.ParseFile(nil, "", "let{f(", 0)
}

https://play.golang.org/p/p0Vco0YNu0z

Appreciate all the work that's gone into this project!

[dop251]

Thanks for reporting!