RFR: JDK-8214529: Exception while using Anonymous class in switch expression

[Maurizio Cimadamore]

Looks good - I agree the program should compile.

Maurizio

On 03/12/2018 12:37, Jan Lahoda wrote:
> Hi,
>
> In:
> https://bugs.openjdk.java.net/browse/JDK-8214529
>
> This is a report that anonymous class' bodies are lost if the 
> anonymous class is the break value. This was due to a mistake in 
> desugaring, and has been fixed alongside with JDK-8214031, which 
> removes the desugaring. But when writing a test for this case, it 
> turned out that "return" statements inside the anonymous class are 
> reported as errors:
>
> ---
> interface TestIntf {
>     default int fun() {
>         return 1;
>     }
> }
>
> public class SwitchTest {
>
>         public static void main(String[] args) {
>                 int x = 10;
>                 var y = switch(x) {
>             case 0 -> new TestIntf(){ public int fun() { return 0; }};
>             default -> new TestIntf(){};
>                         };
>
>                 System.out.println(y.fun());
>         }
> }
> ---
> ---
> $ javac --enable-preview --source 12 /tmp/SwitchTest.java
> /tmp/SwitchTest.java:12: error: return outside of enclosing switch 
> expression
>             case 0 -> new TestIntf(){ public int fun() { return 0; }};
>                                                          ^
> Note: /tmp/SwitchTest.java uses preview language features.
> Note: Recompile with -Xlint:preview for details.
> 1 error
> ---
>
> This is not appropriate, to my knowledge. The proposed fix is to clear 
> the breakResult when creating methodEnv, as is already done for 
> lambdaEnv. The breakResult is (also) used to detect inappropriate 
> returns nested inside the switch expression, so clearing it eliminates 
> the error.
>
> Webrev:
> http://cr.openjdk.java.net/~jlahoda/8214529/webrev.00/
>
> How does this look?
>
> Thanks,
>     Jan
>