Description Ben Davis 2010-07-14 13:12:06 EDT

Build Identifier: M20090211-1700

While resolving an (explicit) 'extends' or 'implements' clause (e.g. extends Object), Eclipse scans all the type names (e.g. BlackCat) made available via static import. If it finds a name that WOULD create a cycle, then it will sometimes report 'cycle detected' even though there isn't one. Whether these spurious errors appear seems to depend on compilation order.

At least, that's my conclusion from the 'steps to reproduce'. What's actually going on may be more complicated, or different entirely.

Reproducible: Sometimes

Steps to Reproduce:
1. Create a project with the following two files. It should compile.
2. Uncomment the static import. The errors should appear.
   - If you don't see the errors, try 'Project -> Clean'.
3. Remove the words "extends Object". The errors disappear.

eclipsecyclebug/BrownBox.java:

package eclipsecyclebug;
import static eclipsecyclebug.GreenBox.*;
public interface BrownBox {
    public static class BlackCat extends Cat {}
}

eclipsecyclebug/GreenBox.java:

package eclipsecyclebug;
//import static eclipsecyclebug.BrownBox.*;
public interface GreenBox {
    public static class Cat extends Object {}
}

The errors:

BrownBox.java: "Cycle detected: a cycle exists in the type hierarchy between BrownBox.BlackCat and GreenBox.Cat"
GreenBox.java: "The hierarchy of type Cat is inconsistent"