The duplicate annotated package-info declaration in the following program crashes javac 9-ea+149:

=== anno/Anno.java ===
package anno;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.PACKAGE)
@Retention(RetentionPolicy.CLASS)
public @interface Anno {}
=== one/package-info.java ===
@anno.Anno
package test;
=== two/package-info.java ===
@anno.Anno
package test;
===

$ javac anno/Anno.java one/package-info.java two/package-info.
java
...
java.lang.AssertionError
        at jdk.compiler/com.sun.tools.javac.util.Assert.error(Assert.java:155)
        at jdk.compiler/com.sun.tools.javac.util.Assert.check(Assert.java:46)
        at jdk.compiler/com.sun.tools.javac.comp.Annotate.lambda$annotateLater$0(Annotate.java:231)
        at jdk.compiler/com.sun.tools.javac.comp.Annotate.flush(Annotate.java:177)
        at jdk.compiler/com.sun.tools.javac.comp.Annotate.unblockAnnotations(Annotate.java:134)
        at jdk.compiler/com.sun.tools.javac.comp.Enter.complete(Enter.java:591)
        at jdk.compiler/com.sun.tools.javac.comp.Enter.main(Enter.java:546)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.enterTrees(JavaCompiler.java:1069)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:940)
        at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:307)
        at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:160)
        at jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:55)
        at jdk.compiler/com.sun.tools.javac.Main.main(Main.java:41)