Symbol.prototype.valueOf.call(x) gives different results than x.valueOf()

[hle0]

Describe the bug

Symbol gives different results depending on how valueOf is called, which causes various tests to fail, like this one for example.

Here's an example session from boa-cli:

>> a = Symbol('s')
Symbol(s)
>> Symbol.prototype.valueOf.call(a) == a.valueOf()
false
>> Symbol.prototype.valueOf.call(a) == a
false
>> a.valueOf() == a
false
>>

To Reproduce
See above. boa-cli was run with cd boa_cli; cargo run.

Expected behavior

The valueOf a Symbol should always == the Symbol, no matter how valueOf is called. Here's an example from Node.js:

> a = Symbol('s')
Symbol(s)
> a.valueOf() == a
true

This behavior should be made the same in Boa.

Build environment (please complete the following information):

• OS: Artix Linux
• Kernel Version: 5.13.12-artix1-1
• Target triple: e.g. x86_64-unknown-linux-gnu
• Rustc version: rustc 1.55.0 (c8dfcfe04 2021-09-06)

Additional context
Add any other context about the problem here.

[jedel1043]

@hle0 Thank you for taking this!

JsSymbol resides on https://github.com/boa-dev/boa/blob/master/boa/src/symbol.rs, and its built-in representation on https://github.com/boa-dev/boa/blob/master/boa/src/builtins/symbol/mod.rs so these should be good starting points.

You can comment here or ping us on discord if you have any questions ☺️