The basic private field support in Bug 1642476 will not correctly run the following test case (as js/src/jit-test/tests/fields/private-eval-in-frame.js)

// |jit-test| --enable-private-fields;
load(libdir + 'asserts.js');
load(libdir + 'evalInFrame.js');

class B {
  #x = 12
  x = 'his'
  ef(str) {
    return evalInFrame(0, str);
  }
}
var b = new B;
assertEq(b.ef(`this.x`), 'his');
assertEq(b.ef(`this.#x`), 12); // Will throw syntax error

This code will throw a syntax error where it ought not to. This is because of the peculiar scope chain used (see this bug for some of the details).

To fix this, we need to generalize this code to allow us to compute the effective scope for these in the general case.

Note: Bug 793345 argues we ought to instead just remove the non-syntactic scope from the debugger which would be the general fix.

https://hg.mozilla.org/mozilla-central/rev/a81d7124a27b