Inferring that what exceptions are thrown from a lambda

[Vicente-Arturo Romero-Zaldivar]

Thanks Esko and Stuart,

The bug has been fixed. The changeset can be seen here: 
http://hg.openjdk.java.net/jdk8/tl/langtools/rev/2375ce96e80d

Vicente

On 07/09/13 17:36, Esko Luontola wrote:
> I submitted the bug, but it didn't tell me any Bug ID; it just gave the
> "Thank You, We will review your report" message.
>
> The title of the bug report is "Inferring the exception thrown by a
> lamdba: sometimes fails to compile", in case you as Oracle employee can
> already see it.
>
>
>
> Stuart Marks wrote on 7.9.2013 2:53:
>> Yep, looks like a bug. I see exactly the behavior you describe.
>>
>> Could you do me a favor and file a bug report with this information at:
>>
>>       http://bugreport.sun.com/bugreport/
>>
>> If you send me or post the bug ID I can transfer it into the right
>> category.
>>
>> Thanks!
>>
>> s'marks
>>
>>
>> On 9/6/13 10:19 AM, Esko Luontola wrote:
>>> Stuart Marks wrote on 4.9.2013 23:11:
>>>> A change to support this went in fairly recently. This now compiles for
>>>> me using JDK 8 b105. It fails with the error you mention when using
>>>> older builds, e.g., JDK 8 b88, which is one I happened to have lying
>>>> around. (Note, I am referring to JDK 8 builds, not Lambda builds.)
>>> I think I found a bug related to that in 1.8.0-ea-b105: when I compile
>>> both files with the same javac command, it compiles, but if I compile
>>> them separately, it doesn't compile.
>>>
>>> Here is how to reproduce the issue. I used the
>>> jdk-8-ea-bin-b105-windows-x64-29_aug_2013.exe build.
>>>
>>> -- Foo.java:
>>> import java.io.IOException;
>>>
>>> class Foo {
>>>
>>>        public void compiles() throws IOException {
>>>            String result = Bar.tryRepeatedly(10, () -> {
>>>                throw new IOException("dummy exception");
>>>            });
>>>        }
>>>
>>>        public void doesNotCompile() {
>>>            String result = Bar.tryRepeatedly(10, () -> "result");
>>>        }
>>>
>>>        public void compilesButUndesirable() throws Throwable {
>>>            String result = Bar.tryRepeatedly(10, () -> "result");
>>>        }
>>> }
>>> --
>>>
>>> -- Bar.java:
>>> class Bar {
>>>        public static <T, E extends Throwable> T tryRepeatedly(int
>>> maxTries, Action<T, E> action) throws E {
>>>            return action.run();
>>>        }
>>> }
>>>
>>> interface Action<T, E extends Throwable> {
>>>        T run() throws E;
>>> }
>>> --
>>>
>>> This command succeeds:
>>>
>>> $ javac Foo.java Bar.java
>>>
>>> But this series of commands fails:
>>>
>>> $ javac Bar.java
>>>
>>> $ javac Foo.java
>>> Foo.java:12: error: unreported exception Throwable; must be caught or
>>> declared to be thrown
>>>            String result = Bar.tryRepeatedly(10, () -> "result");
>>>                                             ^
>>> 1 error
>>>
>>>