Consider this source code (intentionally missing imports):
-----
@Retention(RetentionPolicy.SOURCE)
@interface Anno {
}
-----

Currently, javac won't attribute the "@Retention"'s attributes. As a consequence, the only compile-time error produced is:
-----
Anno.java:1: error: cannot find symbol
@Retention(RetentionPolicy.SOURCE)
 ^
  symbol: class Retention
1 error
-----

Which may be inconvenient for the user - adding an import for "java.lang.annotation.Retention" and recompiling will lead to more compile-time errors:
-----
Anno.java:2: error: cannot find symbol
@Retention(RetentionPolicy.SOURCE)
           ^
  symbol: variable RetentionPolicy
Anno.java:2: error: an enum annotation value must be an enum constant
@Retention(RetentionPolicy.SOURCE)
                          ^
2 errors
-----

It may be more convenient to mark both the Retention and RetentionPolicy as unresolvable in the first case, so that the user knows both need to be imported.

Reproducible with:
$ javac -fullversion
javac full version "1.7.0_11-b21"

and:
$ javac -fullversion
javac full version "1.8.0-ea-b117"