RFR JDK14-8236597: issues inferring type annotations on records

Maurizio Cimadamore maurizio.cimadamore at oracle.com
Fri Jan 10 20:51:08 UTC 2020

On 10/01/2020 19:34, Vicente Romero wrote:
> On 1/10/20 2:23 PM, Maurizio Cimadamore wrote:
>> Looks good - but I have a question - I assume the changes in 
>> TypeEnter are to 'copy' the tree for the return type 'as is' from the 
>> record component declaration to the accessor return type. That is, is 
>> one is a qualified name, the other should be too, and viceversa.
>> Ok, my question then is: shouldn't something like this be said 
>> somewhere in the spec too? After all, since @Nullable foo.bar.Baz is 
>> invalid but @Nullable Baz is not (or should use generate code for 
>> foo.bar. at Nullable Baz ?)
> I'm not sure that we should mention this in the spec as this patch is 
> just generating verbatim the same type typed by the user and thus it 
> would be the expected outcome by the user, unless I'm missing something.
I guess my point here is that it's not sufficient to say that a record 
class has an accessor with this and that type - for type annotations it 
is also relevant which syntactic form is used to express the type (ident 
vs. qualified name). If the syntactic form should be preserved, then I 
think we should say something, otherwise it's not clear exactly which 
type annotations will be applicable to e.g. the accessor and which not.
>> And... what about parameter types? Shouldn't they need same treatment 
>> too?
> they should but I wasn't sure if I should tackle that in this same 
> patch, but I can do a: now that I was in the neighborhood...


>> Maurizio
> Vicente
>> On 10/01/2020 00:34, Vicente Romero wrote:
>>> Hi,
>>> Please review this patch [1] to fix a couple of issues regarding 
>>> inference of type annotations on records [2]. There where two cases 
>>> where type annotations were reported as missing. For compact records 
>>> whose arguments are not inheriting the type annotations from the 
>>> corresponding record component and for accessors for which the 
>>> annotation was present but just as a declaration annotation applied 
>>> to the accessor. Not as a type annotation applied to the return type 
>>> which was the expected outcome.
>>> In the case of the compact constructor, the solution was just to 
>>> copy the annotations to the parameters which were missing. In the 
>>> case of the accessor the solution was a bit more complicated. 
>>> Accessors are created but not added to the list definitions 
>>> belonging to the record tree. This is done to make them invisible to 
>>> type attribution as they are not fully fledge methods, but as a side 
>>> effect they are also invisible to the type annotations machinery. 
>>> For this reason type annotations were not recognized as such. The 
>>> solution here has been to make the type annotations machinery to 
>>> visit accessors for records and set the type annotations correctly. 
>>> In order to do that the accessor method created at TypeEnter is 
>>> stored at the record component and visited at the same time type 
>>> annotations are being classified for the rest of the code.
>>> Thanks,
>>> Vicente
>>> [1] http://cr.openjdk.java.net/~vromero/8236597/webrev.00/
>>> [2] https://bugs.openjdk.java.net/browse/JDK-8236597

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