Updated error message for TS2539

[hailin-zhang]

Fixes #39751

There were a number of different cases using this error code outside of the one reported so I used a more generic error message. Please let me know if a more descriptive message should be used 👍

Thanks!

[ghost]

All CLA requirements met.

[DanielRosenwasser]

Maybe "because it is not a writable binding" or something - immutable really does imply the entire structure is frozen. Maybe @sandersn has a suggestion.

[orta]

because it is not a writable binding

is real jargon-y, perhaps we could narrow down the error handling and explicitly check that it's an import, then offer something like:

Cannot assign to '{0}' because it is imported value which cannot be changed?

[sandersn]

I agree, the baselines show that the error happens on, at least, enum, class, function, namespace, import.

If the error distinguishes those cases, you could probably get away with a very simple error, something like:

Cannot assign to '{0}' because it is an import.

It might even be parametrisable:

Cannot assign to '{0}' because it is a(n) {1}.

Edit: But that assumes you can retrieve the keyword fairly easily. Probably 5 different messages is still the right way to go so that it's easier to localise.

[DanielRosenwasser]

'{0}' declarations like '{1}' cannot be assigned to.

[vuvuzella]

'{0}' declarations like '{1}' cannot be assigned to.

I agree with the word declaration. Another variation can be
Cannot assign to '{0}': Previous '{1}' declaration of the same name exists

[sandersn]

@hailin-zhang do you want to keep working on this?

[hailin-zhang]

@sandersn sorry for the lack of an update, I am OK if somebody wants to take this ticket, if not then I can circle back once I have more time

[sandersn]

I switched to multiple errors, and, since undefined was the only one I didn't cover, switched back to the original message for that, since the original covers undefined nicely.