Is it expected that Document has [LegacyOverrideBuiltIns]?

[yuki3]

I have a question. Maybe I'm just misunderstanding. Please correct me if I'm wrong.

https://html.spec.whatwg.org/multipage/dom.html#htmlorsvgscriptelement

[LegacyOverrideBuiltIns]
partial interface Document {
...(snip)...

// DOM tree accessors
getter object (DOMString name);

Document interface has [LegacyOverrideBuiltIns] in HTML spec. However, Chromium (Blink) doesn't implement [LegacyOverrideBuiltIns] on window.document nor Document nor HTMLDocument. As far as I tested with Firefox and Safari, Firefox and Safari also look not implementing [LegacyOverrideBuiltIns]. If so, is it really the consensus to have [LegacyOverrideBuiltIns]?

I ran the following JS code on Firefox and Safari JS console. The results were the same on both browsers.

document.foo = 3;
form = document.createElement('form');
form.name = 'foo';

document.foo;  // => 3
document.body.appendChild(form);
document.foo;  // => 3 (not `form`)
delete document.foo;  // => true
document.foo;  // => <form name="foo">

[annevk]

This was introduced in f355f4a. The rationale seems to start at https://krijnhoetmer.nl/irc-logs/whatwg/20090113#l-261 and gives http://software.hixie.ch/utilities/js/live-dom-viewer/?%3C!DOCTYPE%20html%3E%0D%0A...%3Ciframe%20name%3Dbody%3E%3C%2Fiframe%3E%3Cscript%3Ew(document.body)%3C%2Fscript%3E as an example.

In your test foo is not a builtin so I'm not sure why you expect it to override that?

[yuki3]

Thanks! I was misunderstanding that [LegacyOverrideBuiltIns] has priority over own properties. It's wrong.
https://webidl.spec.whatwg.org/#dfn-named-property-visibility
explicitly mentions that own properties have priority over anything else regardless of [LegacyOverrideBuiltIns].

My memory was rust. I'm sorry for taking your precious time, and really appreciate you about correcting me. :)