Make ToolchainInfo final to prevent future subclassing.
@@ -38,7 +38,7 @@ import net.starlark.java.syntax.Location;
* additional fields to Starlark code. Also, these are not disjoint.
*/
@Immutable
-public class ToolchainInfo extends NativeInfo implements ToolchainInfoApi {
+public final class ToolchainInfo extends NativeInfo implements ToolchainInfoApi {
/** Name used in Starlark for accessing this provider. */
public static final String STARLARK_NAME = "ToolchainInfo";
