1907234 - Improve error message for class members called "prototype" or "constructor"

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P3)

Description

[Joshua Chen]

Steps to reproduce:

class X {
  constructor = 1;
}

class Y {
  static prototype = 1;
}

Actual results:

Bad error message: "SyntaxError: bad method definition"

There's no method definition here and I probably don't intend to write one. It's the field itself that's invalid.

Expected results:

Something similar to V8's message:

• SyntaxError: Classes may not have a field named 'constructor'
• SyntaxError: Classes may not have a static property named 'prototype'

For more context, I am working on https://github.com/mdn/mdn/issues/505 and the page titles are FF errors, so they need to be descriptive and discoverable.

Comment 1

[Joshua Chen]

I realized this same error is used for any constructor that's not a plain method, such as #constructor and async constructor. If we don't want to make a bunch of error codes for this like V8 does, we should make the message generic like "A class constructor must be declared as a plain method".

Comment 2

[Joshua Chen]

Attachment: Bug 1907234 - split "bad method definition" error into three error messages r=mgaudet

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/264cc00a5cfc
split "bad method definition" error into three error messages r=mgaudet

Comment 4

[pstanciu]

https://hg.mozilla.org/mozilla-central/rev/264cc00a5cfc