Java Eclipse: class cannot be resolved to a type inheritance

Java Eclipse: class cannot be resolved to a type inheritance

I've run into an issue where when I open projects in Eclipse there is
something wrong with the visibility of classes across packages.
Example:
package.a
- public abstract class clazz
package.b
- public abstract class clazzy extends clazz
In the above instance clazzy would have an error, where clazz wouldn't
available. If I move clazzy into package.a, and the move it back to
package.b everything is fine, but otherwise I can't get eclipse to
recognize that clazz exists at all.
EDIT 1:
Yes, I am importing the class. I also press ctrl-shift-o (import). If I
hand type out the import, eclipse still fails to recognize that clazz
exists. I have not tried importing the entire package, as generally I
avoid doing this for a whole variety of reasons.