Bug 186191

Summary:	Consider MasqueradesAsUndefinedObjectType
Product:	WebKit	Reporter:	Yusuke Suzuki <ysuzuki>
Component:	JavaScriptCore	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	fpizlo, keith_miller, mark.lam, saam, ysuzuki
Priority:	P2
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description Yusuke Suzuki 2018-06-01 05:16:10 PDT

MasqueradesAsUndefined is crazy feature,

1. It is introduced for backward compatibility of `if (document.all)` thingy. It is unlikely that MasqueradesAsUndefined objects increases
2. MasqueradesAsUndefined is only used for HTMLAllCollection right now
3. HTMLAllCollection is ObjectType

So, what do we think of folding this information into JSType, and free up MasqueradesAsUndefined TypeInfo flag space?
We can introduce MasqueradesAsUndefinedObjectType for HTMLAllCollection.