Circularity in type lookup due to on-demand type imports

ExtendJ 8.0.1-101-gf92bc19

There is a circular dependency between attributes in the type lookup in ExtendJ causing a stack overflow exception because there is a lack of a circular attribute. The bug may be a bit difficult to understand, but the following test case exposes the problem. The test case consists of several Java files:

Test.java:

// Test a circular import-on-demand dependency.
// The implements clause in pkg/C.java causes type lookup to load the on-demand
// import pkg.D.*, this in turn leads to evaluating the member types of pkg.D,
// which requires loading the on-demand imported types for the import
// declarations in pkg/D.java.  Since the import pkg.C.* is before the import
// pkg.E.* which provides the type X we are looking for, the member type sof
// pkg.C are evaluated first, but leads back to the original on-demand import
// lookup.
// .result=COMPILE_PASS
public class Test extends pkg.C {
}

pkg/C.java:

package pkg;

import pkg.D.*;

public class C implements D.I {
}

pkg/D.java:

package pkg;

import pkg.C.*;
import pkg.E.*;

public class D implements X {
}

pkg/E.java:

package pkg;

public interface E {
  public interface X {
    public interface I {
    }
  }
}

The above test case causes a stack overflow in ExtendJ.

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