Reactivity Transform should respect `const` keyword

[sxzz]

Vue version

3.2.41

Link to minimal reproduction

https://sfc.vuejs.org/#eNp9kE1qw0AMha+iDgW3EHuabXAC3fUG3cxmYivxhPlDGqcL47tXtkspLXSn9/T0IWlSrzk39xHVQbXckcsFGMuYTya6kBMVmIDwAjNcKAWoJFqZaGKXIhcIfIUjPErgqXpD7xO8J/L9Q/W8ZLQGHtLoe8DgCtgISJQIBiTcAbvY4UpwDBZWoI0F7pacPXtsTNzwRu1fjDKx1duCspqIgiF7W1AUQDvsT9O0wua51aJW18U8CrAOqUd/NEr6Rkmr1d/Taqe2O+tgc3PjFOUT0zJtvhps1AFWZ/Hk/kUbNZSS+aA1X7rlfzduEl21VA2NsbiADXKoz5Q+GEnARu1+MLSYd6SaMPbyDfqP+Sv6h7tgZxNnNX8CV7ifXg==

Steps to reproduce

Open the reproduction

What is expected?

Throw an error about const keyword.

What is actually happening?

No errors.

System Info

No response

Any additional comments?

Relate issue #6989

WIP: I'll make a PR later.

[louiss0]

I can't believe people didn't see this as a problem thank goodness. Programming mechanics are important.

[shendiid]

const msg = $ref('Hello World!') === const msg ={ value : 'Hello World!' }
so...msg = '10' === msg.value = '10' // msg = { value : '10' } is allowed
but... const msg = $ref( '10' ) is not allowed.

[sxzz]

It's legal in transformed code, but illegal in the source code at the JavaScript syntax level.

[shendiid]

It's legal in transformed code, but illegal in the source code at the JavaScript syntax level.

I think there is no solution，unless use let.😥

[bbcvc]

This may be a break change. @sxzz

[bbcvc]

This may be a break change. @sxzz

If 👇 is not allowed then there will be a lot of compatibility issues for projects prior to version < 3.2.41.This can cause problems for many users.
`
const msg = $ref('Hello World!')

// should emit an error here, since msg is a constant variable.
msg = "10"
`

[sxzz]

@bbcvc It's not a valid syntax so the IDE or VSCode will emit an error. Example

Even if it's a breaking change, considering that Reactivity Transform is an experimental feature, I think this breaking change is reasonable.

[bbcvc]

@sxzz I think the developer should understand that this is a compiler macros. 👉RFC.
If such a change is to be made, a broader discussion should be obtained in the community.Or modify rfc: https://github.com/vuejs/rfcs

[sxzz]

As RFC mentioned

$() can only be used with let because it would be pointless to declare a constant ref.

[bbcvc]

Answered my doubts. 🫡