[Bug]: Re-assignment to class during static field initialization

[p51lee]

Describe the bug

Mutable assignment to class name should throw TypeError during an initialization of static fields.
However, the transpiled code terminates without any error.

Input code

class x { static y = x = 0 ; }

Config

No response

Playground link

https://play.swc.rs/?version=1.3.11&code=H4sIAAAAAAAAA0vOSSwuVqhQqFYoLkksyUxWqFSwBXJtFQwUrBVqFQB8P0%2FWHwAAAA%3D%3D&config=H4sIAAAAAAAAA0WMTQrEIAxG75K1286id5hDBCctFv9IUhgR714tlu7C915ehUMsrBUyshCPS0pU%2FMMKZAOKZZcVTNf6tKEXagYUeScdiiyd%2BZSEJjUQXHRbGSWbQmYSeRHG3T9m66GQfucYKmjJdAc%2F0N7G%2FHPynaLySe0Cj9ke9LUAAAA%3D

Expected behavior

Mutable assignment to class name should throw TypeError during an initialization of static fields:

$ node input.js
input.js:1
class x { static y = x = 0 ; }
                       ^

TypeError: Assignment to constant variable.
    at <static_initializer> (/Users/p51lee/dev/esmeta-plrg/input.js:1:24)
    at Object.<anonymous> (/Users/p51lee/dev/esmeta-plrg/input.js:1:1)
    at Module._compile (node:internal/modules/cjs/loader:1159:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1213:10)
    at Module.load (node:internal/modules/cjs/loader:1037:32)
    at Module._load (node:internal/modules/cjs/loader:878:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:23:47

Node.js v18.11.0

Actual behavior

The output code terminates without any error.

$ node output.js
// terminates without error

Version

1.3.11 (default SWC playground)

Additional context

No response

[alexander-akait]

hm, babel do the same https://babeljs.io/repl#?browsers=defaults%2C%20not%20ie%2011%2C%20not%20ie_mob%2011&build=&builtIns=false&corejs=3.21&spec=false&loose=false&code_lz=MYGwhgzhAEAe0G9oQC5hQS2NAntAvHAdAAzQDc0AvtEA&debug=false&forceAllTransforms=false&shippedProposals=false&circleciRepo=&evaluate=false&fileSize=false&timeTravel=false&sourceType=module&lineWrap=true&presets=env%2Creact%2Cstage-2&prettier=false&targets=&version=7.20.1&externalPlugins=&assumptions=%7B%7D - no errors and no extra runtime

[p51lee]

I have also submitted a bug report to babel: babel/babel#15000

[Austaras]

I believe swc should report error in this case -- swc reject const reassignment, although it is valid JS. Or we could drop const reassignment lint, that would also make swc consistent.

[kdy1]

I think we should catch this too.

We should move hard errors to compile time as much as possible

[Austaras]

I'm a bit cautious about this -- const reassignment is not "hard error", it's runtime error

try {
    const a = 1
    a = 2
} catch (e) {
    console.log(e)
}

But I don't believe anyone would rely on this.

[kdy1]

Oh, you are right... But same here. I don't expect people to rely on it

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.