Incorrect treatment of declarations named NaN/Infinity/undefined

[gibson042]

Bug Description

There are details at tc39/test262#4332 , but the summary is that Hermes incorrectly fails to reject top-level NaN/Infinity/undefined declarations and incorrectly fails to create (or at least respect) them in a deeper scope such as a block context.

• I have run gradle clean and confirmed this bug does not occur with JSC

Hermes release version: 0.11.0

Steps To Reproduce

code example 1:

print('START');
const NaN = 1;
const Infinity = 1;
const undefined = 1;
print([NaN, Infinity, undefined].some(v => v === 1) ? 'FAIL WITH EFFECTS' : 'FAIL WITHOUT EFFECTS');

code example 2:

{
  const NaN = 1;
  const Infinity = 1;
  const undefined = 1;
  print([
    NaN === 1 ? 'PASS NaN' : 'FAIL NaN',
    Infinity === 1 ? 'PASS Infinity' : 'FAIL Infinity',
    undefined === 1 ? 'PASS undefined' : 'FAIL undefined',
  ].join(', '));
}

The Expected Behavior

Example 1 should throw a SyntaxError before anything happens (but instead prints "START" and "FAIL WITHOUT EFFECTS").

Example 2 should print "PASS NaN, PASS Infinity, PASS undefined" (but instead prints "FAIL NaN, FAIL Infinity, FAIL undefined").

[tmikov]

Both examples pass with Hermes with --block-scoping. Without it, lexical declarations are simply aliases for var (for compatibility with weird internal use cases we have).

In Static Hermes, the second example passes as well, but the first fails. We will look into it (cc: @avp).

[avp]

Fixed in Static Hermes in 2897b34