RFR: JDK-8235778: No compilation error reported when a record is declared in a local class

[Remi Forax]

yes, this code should not compile, a local record should not be able to capture local variables. 
An "inner" record is implicitly static for the same reason. 

Rémi 

> De: "Maurizio Cimadamore" <maurizio.cimadamore at oracle.com>
> À: "Vicente Romero" <vicente.romero at oracle.com>, "compiler-dev"
> <compiler-dev at openjdk.java.net>
> Envoyé: Jeudi 12 Décembre 2019 13:34:38
> Objet: Re: RFR: JDK-8235778: No compilation error reported when a record is
> declared in a local class

> The patch is ok, but I'm still not super convinced about treatment of local
> records; example:

> $ cat TestLocalRecord.java

> class TestLocalRecord {
> void m() {
> String s = "Hello!";
> record A() {
> void m() { System.out.println(s); }
> }
> new A().m();
> }
> }

> $ javap -s TestLocalRecord\$1A.class Compiled from "TestLocalRecord.java"

> final class TestLocalRecord$1A extends java.lang.Record {
> final java.lang.String val$s;
> descriptor: Ljava/lang/String;
> public TestLocalRecord$1A();
> descriptor: (Ljava/lang/String;)V

> void m();
> descriptor: ()V

> public java.lang.String toString();
> descriptor: ()Ljava/lang/String;

> public final int hashCode();
> descriptor: ()I

> public final boolean equals(java.lang.Object);
> descriptor: (Ljava/lang/Object;)Z
> }

> Note the mismatch between the descriptor of the canonical constructor and the
> source signature of the same. This record seems not to be "the whole state and
> nothing but the state" because of the presence of captured fields in there.

> Maurizio

> On 12/12/2019 00:40, Vicente Romero wrote:

>> I have uploaded a new iteration at [1],

>> Thanks for your comments,
>> Vicente

>> [1] [ http://cr.openjdk.java.net/~vromero/8235778/webrev.01/ |
>> http://cr.openjdk.java.net/~vromero/8235778/webrev.01/ ]

>> On 12/11/19 7:08 PM, Maurizio Cimadamore wrote:

>>> If sym.isLocal() returns true, is this check
>>> && (sym.owner.flags_field & STATIC) == 0)
>>> Needed? Aren't we inside a record declaration that is contained in some local
>>> context (e.g. within a method body), whose immediate enclosing type is a type
>>> T? If so, isn't T always non-static? I guess yes, unless T is a record itself,
>>> like:

>>> void m() {
>>> record A() {
>>> record B() { }
>>> }
>>> }

>>> The patch seems to be biased in favor of this - is it deliberate? (also there's
>>> no test around that). Should the spec say something?

>>> Maurizio

>>> On 11/12/2019 23:39, Vicente Romero wrote:

>>>> Hi,

>>>> Please review the fix for [1] at [2]. Records are not allowed to be defined
>>>> inside inner classes. This patch extends the check to local inner classes which
>>>> was missing.

>>>> Thanks,
>>>> Vicente

>>>> [ https://bugs.openjdk.java.net/browse/JDK-8235778 |
>>>> https://bugs.openjdk.java.net/browse/JDK-8235778 ]
>>>> [ http://cr.openjdk.java.net/~vromero/8235778/webrev.00/ |
>>>> http://cr.openjdk.java.net/~vromero/8235778/webrev.00/ ]
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