RFR: JDK-8189248: Jshell /open from file generate error when it tries to upcast to typed instance of other with type inferred from it

[Robert Field]

I believe you want the second argument to setWrap to be “legit” rather than “ins” (as on line 807) so that you don’t attempt to import failed snippet names.

Otherwise looks fine.

It would be good to upgrade the issue Subject so that it will make sense in the future (and include your comments, below).

-Robert

P.S. Apologies, the logic of compileAndLoad is super twisty, I/we should think about a design review.


> On Dec 5, 2017, at 6:02 AM, Jan Lahoda <jan.lahoda at oracle.com> wrote:
> 
> Hi,
> 
> Consider these snippet sent (in this order) to jshell:
> ---
> public class A<T> {
>  private class SomeClass {}
>  public Supplier<T> m() {
>    return new B<>(this);
>  }
> }
> ---
> 
> (note this depends on the future snippet declaring class B)
> 
> ---
> public class B<T> implements Supplier<T> {
>  public B(A<T> a) {}
>  public T get() {return null;}
> }
> ---
> 
> Eval.compileAndLoad will after a few rounds try to compile inputs like:
> ---
> package REPL;
> 
> import java.util.function.Supplier;
> import static REPL.$JShell$3.B;
> 
> class $JShell$2B {
> 
>    public static class A<T>
> ...
> }
> ---
> package REPL;
> 
> import java.util.function.Supplier;
> import static REPL.$JShell$2.A;
> 
> class $JShell$3 {
> 
>    public static class B<T> implements Supplier<T>
> ...
> }
> ----
> 
> Please note that "B" is using the old (pre-Unit.markForReplacement()) version of A from $JShell$2. While the new declaration is inside $JShell$2B. I think this is because the classnames are updates only as setWrap(s) run, so the wraps that run first may still see old classnames for the latter snippets.
> 
> The proposal is to ensure the proper classnames are set before trying to run:
> ins.stream().forEach(u -> u.setWrap(ins, ins));
> which creates the real wraps that are processed.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8189248
> Webrev: http://cr.openjdk.java.net/~jlahoda/8189248/webrev.00/
> 
> How does it look?
> 
> Thanks,
>   Jan