2.1.48 [ECMA-262/9:2018] Section 21.2.6.1 lastIndex

V0082: The [[Writable]] attribute of the lastIndex property cannot be changed from true to false

The specification states:

 21.2.6.1 lastIndex
  
     The value of the lastIndex property specifies the String index at which to start the 
     next match. It is coerced to an integer when used (see 21.2.5.2.2). This property 
     shall have the attributes { [[Writable]]: true, [[Enumerable]]: false, 
     [[Configurable]]: false }.

EdgeHTML Mode

For lastIndex, [[Writable]] cannot be changed from true to false. This operation should be allowed, even though [[Configurable]] is false (see 6.1.7.1).