in src/parser.ts [548:567]
isolateCoverGrammar(parseFunction) {
const previousIsBindingElement = this.context.isBindingElement;
const previousIsAssignmentTarget = this.context.isAssignmentTarget;
const previousFirstCoverInitializedNameError = this.context.firstCoverInitializedNameError;
this.context.isBindingElement = true;
this.context.isAssignmentTarget = true;
this.context.firstCoverInitializedNameError = null;
const result = parseFunction.call(this);
if (this.context.firstCoverInitializedNameError !== null) {
this.throwUnexpectedToken(this.context.firstCoverInitializedNameError);
}
this.context.isBindingElement = previousIsBindingElement;
this.context.isAssignmentTarget = previousIsAssignmentTarget;
this.context.firstCoverInitializedNameError = previousFirstCoverInitializedNameError;
return result;
}