String#matchAll polyfill should throw on non-global regex

[teppeis]

"foo".matchAll(/foo/) should throw but current polyfill doesn't.
Previously it didn't throw, but spec was changed on Oct 2019 TC39 meeting.

• Normative: make String.prototype.matchAll throw for non-global regular expressions tc39/ecma262#1716
• Throw if searchValue is a non-global RegExp tc39/proposal-string-replaceall#24

closure-compiler/src/com/google/javascript/jscomp/js/es6/string/matchall.js

Lines 44 to 47 in 60f0812

	// The spec says it should be an error to pass a non-global RegExp to
	// matchAll, but MDN and Chrome agree that a single match should be done
	// instead.
	var matchOnlyOnce = regexp instanceof RegExp && !regexp.global;

but MDN and Chrome agree that a single match should be done instead.

MDN is not updated yet.
Chrome 80, Firefox 73, Safari TP and core-js have already implemented the new behavior.
https://kangax.github.io/compat-table/es2016plus/

I think Closure Compiler polyfill should follow the latest spec and major browsers.

[brad4d]

Thanks for pointing this out.
We noticed the discrepancy, but decided to implement what our current Chrome browser & MDN said the behavior should be while we gathered more info.

I actually got a response from the v8 team and had just filed a bug requesting we change our polyfill behavior just before I saw this GitHub issue.