Use of private fields with noImplicitAny triggers TS7008

[RomainMuller]

TypeScript Version: 3.8.0-dev.20200205

Search Terms:

• "#private" noImplicitAny
• "#private" TS7008

Code

// tsconfig.json (in "foo" and "bar" modules)
{
  "compilerOptions": {
    "target": "ES2018",
    "noImplicitAny": true,
    "declaration": true
  }
}

// In module "foo", "index.ts"
export class Foo {
  readonly #bar: string = 'baz';

  public get bar() {
    return this.#bar;
  }
}

// in module "bar", "index.ts"
import { Foo } from 'foo';

new Foo();

Expected behavior:
I can declare private fields in classes exported by one package/module, and consume that from another package/module without issues.

Actual behavior:
The module that contains the private fields yields a #private declaration that triggers the noImplicitAny error when it's imported from the other module:

// "index.d.ts" in module "foo"
export declare class Foo {
    #private;
//  ~~~~~~~~ error TSC7008: Member '#private' implicitly has an 'any' type
    get bar(): string;
}

Related Issues: Similar to #6415, except with private-named fields.

[ajafff]

Simplified code which reproduces in the playground: http://www.typescriptlang.org/play/?ts=3.8.0-dev.20200204&ssl=1&ssc=1&pln=3&pc=2#code/CYUwxgNghgTiAEkoGdnwMLwN4Ch7-gGIAHGAe2IG4cBfIA

declare class C {
    #prop;
}

PR incoming.