A simple patch to enable the check to enforce no duplicate provides in module-info.java.extra, same checks as javac. This check was disabled in the fix for JDK-8202941 because of duplicated provides generated for jdk.internal.vm.compiler. Since JDK-8208463 is now resolved [1], we can enable this check.
Webrev: http://cr.openjdk.java.net/~mchung/jdk12/webrevs/8167314/webrev.00/ Mandy [1] http://hg.openjdk.java.net/jdk/jdk/rev/c5461fe16efb
