BUG: local type inference -> symbol not found

[Maurizio Cimadamore]

It would be interesting to know what is the inferred type for `someDao` 
- here's a dirty trick that you can use to let the compiler cough that up:

final var someDao = ...
String s = (String)someDao;

This should hopefully cause a type mismatch and the compiler should tell 
you which type it tried to convert to String.

I'm suspecting that this type might be a non-denotable type (e.g. 
anonymous class type, or intersection type) - which might be something 
that might trip javac up  when used as a method reference receivers?

Maurizio

On 08/06/2020 20:34, Sietse Au wrote:
>
> Hi,
>
> I've run into a compilation error on OpenJDK 11.06 (see attachment) 
> where there is some interaction between local type inference and 
> method reference.
>
> Haven't been able to create a clean project to reproduce the problem.
>
> Inside a larger code-base it is reproducible:
>
> final var someDao = ...
> someRequest.map(item -> SomeBuilder.builder()
>    ...
>    .build()
> ).forEach(someDao::create);
>
> the combination of the local type inference `final var` and the 
> `someDao::create` method reference lead to the stacktrace in the 
> attachment.
>
> When we rewrite the above to not use type inference and declare the 
> type explicitly:
> final SomeDao someDao = ...
>
> OR
>
> rewrite the forEach not using the method reference:
> forEach(x -> someDao.create(x))
>
> the code compiles.
>
> As the stack trace itself was kind of unhelpful, hooking up to a 
> debugger found that when the code hits `someDao::create` a 
> SymbolNotFound error is thrown.
>
>
> Best regards,
> -- 
> Sietse Au
>
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