On Wed, 4 May 2022 10:51:38 GMT, Maurizio Cimadamore <mcimadam...@openjdk.org> wrote:
>> 8262889: Compiler implementation for Record Patterns >> >> A first version of a patch that introduces record patterns into javac as a >> preview feature. For the specification, please see: >> http://cr.openjdk.java.net/~gbierman/jep427+405/jep427+405-20220426/specs/patterns-switch-record-patterns-jls.html >> >> There are two notable tricky parts: >> -in the parser, it was necessary to improve the `analyzePattern` method to >> handle nested/record patterns, while still keeping error recovery reasonable >> -in the `TransPatterns`, the desugaring of the record patterns is very >> straightforward - effectivelly the record patterns are desugared into >> guards/conditions. This will likely be improved in some future >> version/preview >> >> `MatchException` has been extended to cover additional cases related to >> record patterns. > > src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java line 824: > >> 822: } >> 823: for (Symbol currentType : nestedCovered) { >> 824: if (types.isSubtype(types.erasure(currentType.type), > > Not 100% what this test does I think this is i) from the domination relation: > A record pattern with type R and record component pattern list L dominates > another record pattern with type S and record component pattern list M if (i) > the erasure of S is a subtype of the erasure of R, and (ii) every pattern, if > any, in L dominates the corresponding pattern in M. ------------- PR: https://git.openjdk.java.net/jdk/pull/8516
