Error in inlining with object field access: the bound variable is not substituted in the generated code.

This progam
```ml
let foo x = int_of_string x != 3

let badInlining obj =
  if (foo obj##field)
  then  ()
```

compiles to
```js
var Caml_format = require('bs_caml_format');

function foo(x) {
  return +(Caml_format.caml_int_of_string(x) !== 3);
}

function badInlining() {
  Caml_format.caml_int_of_string(x) !== 3;
  return /* () */0;
}
```