ocsigen/js_of_ocaml — pull request #56 by hhugo (2013-11-09 21:56:45+00:00)
Title: COMPILER: improve approximation

check the approximation of Param

example:
```
let s = "qwer"
let r = "poiu"
let f s = print_int (String.length s)
let _ = f s;f r
```
if `f` does't escape, we know that `String.length s` will always be 4