I think this check should probably be in, though I share laz's concern about breaking code.
I'm having trouble thinking of cases where someone might be relying on this whilest the code still works, short of really awful things where variables are named dynamically by making strings and evaling them.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
I think this check should probably be in, though I share laz's concern about breaking code.
I'm having trouble thinking of cases where someone might be relying on this whilest the code still works, short of really awful things where variables are named dynamically by making strings and evaling them.