Program: 45249
Project: 45249
Buggy source:
/** 
 * Creates   {@link PsiReference} for &lt;st:include page="..." /> attribute.
 */
private PsiReference[] onAttributeValue(final XmlAttributeValue xav){
  PsiElement _xa=xav.getParent();
  if (!(_xa instanceof XmlAttribute))   return PsiReference.EMPTY_ARRAY;
  XmlAttribute a=(XmlAttribute)_xa;
  if (!a.getName().equals("String_Node_Str"))   return PsiReference.EMPTY_ARRAY;
  XmlTag p=a.getParent();
  if (p == null)   return PsiReference.EMPTY_ARRAY;
  if (!p.getLocalName().equals("String_Node_Str") || !p.getNamespace().equals("String_Node_Str"))   return PsiReference.EMPTY_ARRAY;
  if (p.getAttribute("String_Node_Str") == null && p.getAttribute("String_Node_Str") == null) {
    return array(new PsiReferenceBase<XmlAttributeValue>(xav,TextRange.from(1,xav.getTextLength() - 2)){
      private final String page=xav.getValue();
      public PsiFile resolve(){
        JavaPsiFacade javaFacade=JavaPsiFacade.getInstance(xav.getProject());
        if (page.startsWith("String_Node_Str")) {
          String pkg=page.substring(1,page.lastIndexOf('/')).replace('/','.');
          PsiPackage jpkg=javaFacade.findPackage(pkg);
          if (jpkg == null)           return null;
          for (          PsiDirectory dir : jpkg.getDirectories()) {
            PsiFile f=dir.findFile(page.substring(page.lastIndexOf('/') + 1));
            if (f != null)             return f;
          }
          return null;
        }
 else {
          PsiFile f=xav.getContainingFile();
          PsiDirectory p=f.getParent();
          if (p == null)           return null;
          PsiFile target=p.findFile(page);
          if (target != null)           return target;
          JavaDirectoryService jds=JavaDirectoryService.getInstance();
          PsiPackage pkg=jds.getPackage(p);
          if (pkg == null)           return null;
          Module m=ModuleUtil.findModuleForFile(f.getVirtualFile(),f.getProject());
          PsiClass c=javaFacade.findClass(pkg.getName(),GlobalSearchScope.moduleWithDependenciesAndLibrariesScope(m));
          if (c == null)           return null;
          c=c.getSuperClass();
          for (; c != null; c=c.getSuperClass()) {
            pkg=javaFacade.findPackage(c.getQualifiedName());
            if (pkg != null) {
              for (              PsiDirectory dir : pkg.getDirectories()) {
                target=dir.findFile(page);
                if (target != null)                 return f;
              }
            }
          }
          return null;
        }
      }
      public Object[] getVariants(){
        return ArrayUtils.EMPTY_OBJECT_ARRAY;
      }
    }
);
  }
  return PsiReference.EMPTY_ARRAY;
}

Fixed version (ground truth):
/** 
 * Creates   {@link PsiReference} for &lt;st:include page="..." /> attribute.
 */
private PsiReference[] onAttributeValue(final XmlAttributeValue xav){
  PsiElement _xa=xav.getParent();
  if (!(_xa instanceof XmlAttribute))   return PsiReference.EMPTY_ARRAY;
  XmlAttribute a=(XmlAttribute)_xa;
  if (!a.getName().equals("String_Node_Str"))   return PsiReference.EMPTY_ARRAY;
  XmlTag p=a.getParent();
  if (p == null)   return PsiReference.EMPTY_ARRAY;
  if (!p.getLocalName().equals("String_Node_Str") || !p.getNamespace().equals("String_Node_Str"))   return PsiReference.EMPTY_ARRAY;
  if (p.getAttribute("String_Node_Str") == null && p.getAttribute("String_Node_Str") == null) {
    return array(new PsiReferenceBase<XmlAttributeValue>(xav,TextRange.from(1,xav.getTextLength() - 2)){
      private final String page=xav.getValue();
      public PsiFile resolve(){
        JavaPsiFacade javaFacade=JavaPsiFacade.getInstance(xav.getProject());
        if (page.startsWith("String_Node_Str")) {
          String pkg=page.substring(1,page.lastIndexOf('/')).replace('/','.');
          PsiPackage jpkg=javaFacade.findPackage(pkg);
          if (jpkg == null)           return null;
          for (          PsiDirectory dir : jpkg.getDirectories()) {
            PsiFile f=dir.findFile(page.substring(page.lastIndexOf('/') + 1));
            if (f != null)             return f;
          }
          return null;
        }
 else {
          PsiFile f=xav.getContainingFile();
          PsiDirectory p=f.getParent();
          if (p == null)           return null;
          PsiFile target=p.findFile(page);
          if (target != null)           return target;
          JavaDirectoryService jds=JavaDirectoryService.getInstance();
          PsiPackage pkg=jds.getPackage(p);
          if (pkg == null)           return null;
          Module m=ModuleUtil.findModuleForFile(f.getVirtualFile(),f.getProject());
          PsiClass c=javaFacade.findClass(pkg.getQualifiedName(),GlobalSearchScope.moduleWithDependenciesAndLibrariesScope(m));
          if (c == null)           return null;
          c=c.getSuperClass();
          for (; c != null; c=c.getSuperClass()) {
            pkg=javaFacade.findPackage(c.getQualifiedName());
            if (pkg != null) {
              for (              PsiDirectory dir : pkg.getDirectories()) {
                target=dir.findFile(page);
                if (target != null)                 return target;
              }
            }
          }
          return null;
        }
      }
      public Object[] getVariants(){
        return ArrayUtils.EMPTY_OBJECT_ARRAY;
      }
    }
);
  }
  return PsiReference.EMPTY_ARRAY;
}