TypeScript Version:

1.8.10

Code

export interface MyInterface {
  foo(): void;
}

export class MyImplementation extends MyInterface {
  public foo(): void {
    console.log("foo!");
  }
}

Expected behavior:
Error TSXXXX: Cannot 'extend' interface. Use 'implements' instead.
Actual behavior:
Error TS2304: Cannot find name 'MyInterface'.