Incorrect reference flags for `x++` and `x--` about oxc HOT 3 CLOSED

This seems to be intentional

Same behavior in no_unused_private_class_members rule

But I think x += 1 should be flagged as Write because x is never used for reading. I believe this variable can be safely removed by the Minifier/Compressor.

Does this make sense?

from oxc.

Hmm. I'm not clear what these flags are meant to represent now!

These are all (broadly) equivalent:

x = x + 1; // Read + Write
x += 1; // Read | Write
x++; // Write
++x; // Write

NB: Also depends on what x is. If it's an object with a valueOf method, the any of the above can have side effects.

This also seems to be inconsistent - it flags x as Read | Write where it could be just Write:

let x = 1;
let y = x = 2;

playground

And something strange going on here - the addition of console.log makes x Read | Write:

console.log;
let x = 1;
x++;

playground

from oxc.

Hmm. I'm not clear what these flags are meant to represent now!
These are all (broadly) equivalent:

x = x + 1; // Read + Write
x += 1; // Read | Write
x++; // Write
++x; // Write

The x = x + 1 is not equivalent. This assignment expression has two references. x + 1 will be flagged Read and x = will be flagged Write

NB: Also depends on what x is. If it's an object with a valueOf method, the any of the above can have side effects.

Yes! I forgot the valueOf method.

This also seems to be inconsistent - it flags x as Read | Write where it could be just Write:

let x = 1;
let y = x = 2;

playground

This case is correct. x = 2 should be flagged as Write and y = x should be flagged as Read

And something strange going on here - the addition of console.log makes x Read | Write:

console.log;
let x = 1;
x++;

playground

This is a bug! I will fix it.

from oxc.