Implement WebIDL sequence arguments correctly

[Ms2ger]

We do something silly right now with arrays rather than with Symbol.iterator, as the spec says.

See servo/rust-mozjs#226, #544, #9056.

[frewsxcv]

cc @ecoal95

[nox]

@emilio @frewsxcv Was this fixed in the end?

[jdm]

I don't believe so: https://github.com/servo/rust-mozjs/blob/3de4ff3d52361a47a17e3b4fcb02c779b99d93d4/src/conversions.rs#L611-L625 vs. https://heycam.github.io/webidl/#es-sequence

[saschanaz]

I don't believe so: https://github.com/servo/rust-mozjs/blob/3de4ff3d52361a47a17e3b4fcb02c779b99d93d4/src/conversions.rs#L611-L625 vs. https://heycam.github.io/webidl/#es-sequence

That code seems to internally use Symbole.iterator and also match the corresponding Gecko code.

Edit: And it in fact supports Symbol.iterator.

const params = new URLSearchParams({
  *[Symbol.iterator]() {
    yield {
      *[Symbol.iterator]() {
        yield "ABC";
        yield "BCD";
      }
    };
  }
}).toString();
// returns "ABC=BCD" as expected

[jdm]

I guess we're done here!