in javac-ast-extension/src/org/jetbrains/jps/javac/ast/JavacTreeRefScanner.java [285:295]
private static Element getClassOrPackageParent(Element element) {
element = element.getEnclosingElement();
while (element != null) {
ElementKind kind = element.getKind();
if (kind.isClass() || kind.isInterface() || kind == ElementKind.PACKAGE) {
return element;
}
element = element.getEnclosingElement();
}
return null;
}