Decorator mixin intellisense working improperly

TypeScript Version: 3.8.3

Search Terms:
Intellisense
Decorator
Mixin
Interface

Code

// A *self-contained* demonstration of the problem follows...
// Test this by running `tsc` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.

class AccountSchema {
// Implementation
}

abstract class AccountLoginSchema {
username: string;
password: string;
getTokenID() {
  // Implementation
}
}

interface CustomerSchema extends AccountLoginSchema {}
@Mixin(AccountLoginSchema) class CustomerSchema extends AccountSchema {
  constructor() {
    super();
    // Intellisense showing up
    this.getTokenID();
  }

// Intellisense not showing up
 getToken

}

Expected behavior:

1. Invoking method, 2) accessing property, 3) redefining method implementation should display intellisense.

Actual behavior:
1 and 2 works, however 3 doesn't display intellisense properly.

Playground Link:

https://www.typescriptlang.org/play?ssl=25&ssc=68&pln=25&pc=8#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

Related Issues:

Start with the self-contained TypeScript example and the linked Playground reproduction, using the reported TypeScript 3.8.3 version as context. Compare IntelliSense for invoking a mixin method, accessing a property, and redefining the method; done means all three expected completion behaviors work consistently.