error TS5055: Cannot write file 'b.js' because it would overwrite input file.
  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.


!!! error TS5055: Cannot write file 'b.js' because it would overwrite input file.
!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
==== a.ts (0 errors) ====
    export class A<T> {}
    
==== b.js (0 errors) ====
    import { A } from './a.js';
    
    /** @extends {A} */
    export class B1 extends A {
        constructor() {
            super();
        }
    }
    
    /** @extends {A<string>} */
    export class B2 extends A {
        constructor() {
            super();
        }
    }
    
    /** @extends {A<string, string>} */
    export class B3 extends A {
        constructor() {
            super();
        }
    }