let consider following snippet

package goo
package inner

class SomeTestClass {
  def foo(silent: Boolean) = {
    (new Inner1).inner.foo()
  }
  private class Inner1 {
    def inner = Inner

    object Inner {
      def foo(silent: Boolean = false): String =
        "trala".nonEmpty.toString() // <- BREAKPOINT HERE
    }
  }
}

set 'window -> preferences -> scala -> debug -> expression evaluator -> add imports from current file' to false (uncheck it)
and stop in breakpoint in line with comment 'BREAKPOINT HERE'
then in Expression Evaluator view evaluate

val a = 5

then you experience an error: "scala.reflect.runtime.ReflectError: object SomeTestClass is not a package".
The problem is in the way how inner import is constructed:

{
  import goo.inner._;
  import org.scalaide.debug.internal.expression.context._;
  import org.scalaide.debug.internal.expression.proxies._;
  import org.scalaide.debug.internal.expression.proxies.primitives._;
  {
    val __this: goo.inner.SomeTestClass.Inner1.Inner.type = JdiContext.placeholder;
    import __this._;
    {
      val a = 5;
      ()
    }
  }
}

we see:

val __this: goo.inner.SomeTestClass.Inner1.Inner.type = JdiContext.placeholder;

and probably expect:

val __this: goo.inner.SomeTestClass#Inner1#Inner.type = JdiContext.placeholder;