RFR: 8282274: Compiler implementation for Pattern Matching for switch (Third Preview) [v5]

Vicente Romero vromero at openjdk.java.net
Wed Apr 20 15:37:28 UTC 2022

On Tue, 19 Apr 2022 18:47:16 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

>> This is a (preliminary) patch for javac implementation for the third preview of pattern matching for switch (type patterns in switches).
>> Draft JLS:
>> http://cr.openjdk.java.net/~gbierman/PatternSwitchPlusRecordPatterns/PatternSwitchPlusRecordPatterns-20220407/specs/patterns-switch-jls.html
>> The changes are:
>> -there are no guarded patterns anymore, guards are not bound to the CaseElement (JLS 15.28)
>> -a new contextual keyword `when` is used to add a guard, instead of `&&`
>> -`null` selector value is handled on switch level (if a switch has `case null`, it is used, otherwise a NPE is thrown), rather than on pattern matching level.
>> -total patterns are allowed in `instanceof`
>> -`java.lang.MatchException` is added for the case where a switch is exhaustive (due to sealed types) at compile-time, but not at runtime.
>> Feedback is welcome!
>> Thanks!
> Jan Lahoda has updated the pull request incrementally with one additional commit since the last revision:
>   Cleanup - more total -> unconditional pattern renaming.

src/jdk.compiler/share/classes/com/sun/tools/javac/tree/TreeMaker.java line 2:

> 1: /*
> 2:  * Copyright (c) 1999, 20222, Oracle and/or its affiliates. All rights reserved.

typo: `20222` instead of `2022`


PR: https://git.openjdk.java.net/jdk/pull/8182

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