1681567 - Default constructors and spread operations

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task, P2)

Description

[Yulia Startsev [:yulia]]

delete Array.prototype[Symbol.iterator];
new class extends class {} {}

Running this code causes the default class constructor to be overriden by using Symbol.iterator. The change is to Stops delegating to Array.prototype[Symbol.iterator] in a default class constructor.

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1681567 - Part 1: Use IsSpreadOp() to detect spread calls. r=tcampbell!

When bug 762363 originally added this code, JOF_SPREAD didn't yet exist, so
instead we used JOF_BYTE, because the only calls using JOF_BYTE are spread
calls.

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1681567 - Part 2: No longer execute spread iteration in default derived class constructors. r=tcampbell!

Implement the spread iteration changes from https://github.com/tc39/ecma262/pull/2216.

Default derived class constructors are changed to longer use array iteration
in the spread super call super(...args). Instead the contents of the args
array are directly passed through to the super call. In our implementation we
can simply pass the args rest-array to the super call.

Depends on D104405

Comment 3

[André Bargull [:anba]]

Attachment: Bug 1681567 - Part 3: Calling class constructors throws from the callee's realm. r=tcampbell!

Second part of the changes from https://github.com/tc39/ecma262/pull/2216.

The TypeError when calling a class constructor is now spec'ed to originate from
the callee realm, so the error code had to be moved after the AutoRealm.

Depends on D104406

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9bbc123e5b38
Part 1: Use IsSpreadOp() to detect spread calls. r=tcampbell
https://hg.mozilla.org/integration/autoland/rev/e120285e8bb4
Part 2: No longer execute spread iteration in default derived class constructors. r=tcampbell
https://hg.mozilla.org/integration/autoland/rev/78e57707b124
Part 3: Calling class constructors throws from the callee's realm. r=tcampbell

Comment 5

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/9bbc123e5b38
https://hg.mozilla.org/mozilla-central/rev/e120285e8bb4
https://hg.mozilla.org/mozilla-central/rev/78e57707b124