} else if (type.isAssignableFrom(previousType)) {
jsoSingleImpls.put(intf, type);
} else if (type.isAssignableTo(previousType)) {
// Do nothing
} else {
throw new InternalCompilerException(
"Already seen an implementing JSO subtype ("
+ previousType.getName() + ") for interface ("
+ intf.getName() + ") while examining newly-added type ("
+ type.getName() + "). This is a bug in "
+ "JSORestrictionsChecker.");