RFR: 8267578: Remove unnecessary preview checks

[Guoxiong Li]

On Sun, 23 May 2021 17:43:45 GMT, Jim Laskey <jlaskey at openjdk.org> wrote:

>> Hi all,
>> 
>> The following preview checks are unnecessary because they are standard features now.
>> 
>> Attr.java
>> 
>>         allowReifiableTypesInInstanceof =
>>                 Feature.REIFIABLE_TYPES_INSTANCEOF.allowedInSource(source) &&
>>                 (!preview.isPreview(Feature.REIFIABLE_TYPES_INSTANCEOF) || preview.isEnabled());
>> 
>> 
>> JavacParser.java
>> 
>>         this.allowYieldStatement = (!preview.isPreview(Feature.SWITCH_EXPRESSION) || preview.isEnabled()) &&
>>                 Feature.SWITCH_EXPRESSION.allowedInSource(source);
>> 
>> 
>> Resolve.java
>> 
>>         allowYieldStatement = (!preview.isPreview(Feature.SWITCH_EXPRESSION) || preview.isEnabled()) &&
>>                 Feature.SWITCH_EXPRESSION.allowedInSource(source);
>> 
>> 
>> It is good to remove them.
>> Thanks for review.
>> 
>> Best Regards,
>> -- Guoxiong
>
> These checks need to remain to allow the Javac compiler to generate code for earlier releases. Please close.

@JimLaskey @jonathan-gibbons @lahodaj Thanks for your comments and reviews.

This patch only cleans up the preview checks instead of something about releases.

The similar cleanup codes are common when we implement the standard feature. Please see the following two cases.

1. [8260517: implement Sealed Classes as a standard feature in Java](https://github.com/openjdk/jdk/commit/0fa9223)


-        this.allowSealedTypes = (!preview.isPreview(Feature.SEALED_CLASSES) || preview.isEnabled()) &&
-                Feature.SEALED_CLASSES.allowedInSource(source);
+        this.allowSealedTypes = Feature.SEALED_CLASSES.allowedInSource(source);


2. [8255013: implement Record Classes as a standard feature in Java, follow-up](https://github.com/openjdk/jdk/commit/8bde2f4)


-        this.allowRecords = (!preview.isPreview(Feature.RECORDS) || preview.isEnabled()) &&
-                Feature.RECORDS.allowedInSource(source);
+        this.allowRecords = Feature.RECORDS.allowedInSource(source);


We can consider that the codes of this patch were forgotten to cleanup during previous standard features.

-------------

PR: https://git.openjdk.java.net/jdk/pull/4157