[type-annos-observers] ordering of annotated array brackets

[Markus Keller]

Alex Buckley <alex.buckley at oracle.com> wrote on 2014-03-19 19:33:43:
> I understand the a2[0]=a1 scenario. Since making it well-typed means 
> redefining the array type construction rule to consider post-identifier 
> [] first, I am happy for a2[0]=a1 to not be well typed. There is a 
> simple fix here: declare a1 and a2 in different declarations.

Wasn't it a no-go in the past to require users to rewrite existing code?
http://mail.openjdk.java.net/pipermail/type-annotations-spec-observers/2013-January/000064.html

Not adding new features to deprecated constructs would have been fine, but 
adding them in an inconsistent way is really bad.

The too simple "left-to-right" rule also makes simple refactorings a pain, 
e.g. replacing a type parameter by a concrete type:

import static java.lang.annotation.ElementType.TYPE_USE;
import java.lang.annotation.*;

@Target(TYPE_USE)
@interface NonEmpty {}

public class Test {
    public API<String @NonEmpty []> api;
    public API2 api2;

    void test() {
        api.t = api.ts[0]; // OK
        api2.t = api2.ts[0]; // Not OK?
    }
}

class API<T> {
    public T t, ts[];
    void assign() {
        t = ts[0]; // OK
    }
}

class API2 {
    public String @NonEmpty [] t, ts[];
    void assign() {
        t = ts[0]; // Not OK?
    }
}