src/vs/editor/standalone/common/monarch/monarchLexer.ts/MonarchLineState/clone
class MonarchLineState:	public clone(): languages.IState {
		const embeddedlanguageDataClone = this.embeddedLanguageData ? this.embeddedLanguageData.clone() : null;
		// save an object
		if (embeddedlanguageDataClone === this.embeddedLanguageData) {
			return this;
		}
		return MonarchLineStateFactory.create(this.stack, this.embeddedLanguageData);
	}