[Bug] when ThisExpression marked as Purish, deadcode plugin will remove arrowy function plugin build result

[SoloJiang]

Bug Report

@babel/types @7.12.5:
This pr marked ThisExpression as Purish, it will cause babel-plugin-minify-dead-code-elimination removes @babel/plugin-transform-arrow-functions compiled result.
For example:

<div onClick={() => {
  this.a = 1;
} }></div>

It will be transformed by @babel/plugin-transform-arrow-functions:

var _this = this
<div onClick={function() {
  _this.a = 1;
} }></div>

After this pr, it will be transformed as:

<div onClick={function() {
  this.a = 1;
} }></div>

So, the this will be undefined.

[babel-bot]

Hey @SoloJiang! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite."

[divcris]

so, @babel/types version I go back to 7.12.1 to temp solve this problem

[xqin]

Please revoke this version!!!!

[salvoravida]

please fix it!!

you are breaking CI builds!!!!!

[xqin]

can we publish new version v7.12.6 as soon as possible?

[nicolo-ribaudo]

I'll release once CI on main finishes

[nicolo-ribaudo]

Published as @babel/types@7.12.6!