(plugin dts) Error: Syntax not yet supported

[cjh980402]

Checklist

• I can reproduce this issue when running this plugin on its own.
  Other plugins, such as node-resolve are known to cause issues.
• I am running this plugin on .d.ts files generated by TypeScript.
  The plugin can consume .ts and even .js files (with allowJs: true), but this is known to cause issues.
• This issue is not related to rolling up @types.
  The plugin ignores these by default, unless respectExternal is set. @types can contain hand-crafted code which is known to cause issues.

I got error when I use extends null.
egoist/tsup#500

Code Snipped

To reproduce that error, I changed ./build/src/index.ts.

// Your code that is causing problems.
import { PluginImpl } from "rollup";
import ts from "typescript";

export class MyClass extends null {
  static a = 10;
}
export interface Options {
    /**
     * The plugin will by default flag *all* external libraries as `external`,
     * and thus prevent them from be bundled.
     * If you set the `respectExternal` option to `true`, the plugin will not do
     * any default classification, but rather use the `external` option as
     * configured via rollup.
     */
    respectExternal?: boolean;
    /**
     * In case you want to use TypeScript path-mapping feature, using the
     * `baseUrl` and `paths` properties, you can pass in `compilerOptions`.
     */
    compilerOptions?: ts.CompilerOptions;
}
declare const plugin: PluginImpl<Options>;
export default plugin;

Error Message

Change the ./build/src/index.ts and run command npm run build.

// The Error Message thrown by rollup / the plugin.
./.build/src/index.js → ./dist/rollup-plugin-dts.mjs, ./dist/rollup-plugin-dts.cjs...
created ./dist/rollup-plugin-dts.mjs, ./dist/rollup-plugin-dts.cjs in 188ms

./.build/src/index.d.ts → ./dist/rollup-plugin-dts.d.ts...
[!] (plugin dts) Error: Syntax not yet supported

  2 | import ts from "typescript";
  3 |
> 4 | declare class MyClass extends null {
    |                               ^^^^
  5 |   static a = 10;
  6 | }
  7 | interface Options {
.build/src/index.d.ts
Error: Syntax not yet supported

  2 | import ts from "typescript";
  3 |
> 4 | declare class MyClass extends null {
    |                               ^^^^
  5 |   static a = 10;
  6 | }
  7 | interface Options {
    at convertExpression (/home/ubuntu/github-clone/test/rollup-plugin-dts/.build/rollup.config.js:451:15)
    at DeclarationScope.convertHeritageClauses (/home/ubuntu/github-clone/test/rollup-plugin-dts/.build/rollup.config.js:920:36)
    at Transformer.convertClassOrInterfaceDeclaration (/home/ubuntu/github-clone/test/rollup-plugin-dts/.build/rollup.config.js:1279:15)
    at Transformer.convertStatement (/home/ubuntu/github-clone/test/rollup-plugin-dts/.build/rollup.config.js:1215:25)
    at new Transformer (/home/ubuntu/github-clone/test/rollup-plugin-dts/.build/rollup.config.js:1166:18)
    at convert (/home/ubuntu/github-clone/test/rollup-plugin-dts/.build/rollup.config.js:1157:25)
    at Object.transform (/home/ubuntu/github-clone/test/rollup-plugin-dts/.build/rollup.config.js:1473:31)
    at transformFile (/home/ubuntu/github-clone/test/rollup-plugin-dts/.build/rollup.config.js:1571:50)
    at Object.transform (/home/ubuntu/github-clone/test/rollup-plugin-dts/.build/rollup.config.js:1578:33)
    at /home/ubuntu/github-clone/test/rollup-plugin-dts/node_modules/rollup/dist/shared/rollup.js:22706:25