Unhelpful `--strictFunctionTypes` error when first method is `self(): this;`

TypeScript Version: 2.7.0-dev.20171214

Code

declare class C<T> {
    self(): this;
    covariant(): T;
    contravariant: (t: T) => void;
    m(other: C<{}>): void;
}

new C<number>().m(new C<number>());

Expected behavior:

Error that C<number> isn't C<{}> because C<{}>'s contravariant can accept (t: {}) but C<number> can only accept (t: number).

Actual behavior:

src/a.ts(8,19): error TS2345: Argument of type 'C<number>' is not assignable to parameter of type 'C<{}>'.
  Types of property 'self' are incompatible.
    Type '() => C<number>' is not assignable to type '() => C<{}>'.
      Type 'C<number>' is not assignable to type 'C<{}>'.

Riprodurre il problema con lo snippet TypeScript nel report usando --strictFunctionTypes e confrontare la diagnostica con il comportamento previsto indicato. Tracciare il confronto dei tipi attivato dal primo metodo self(): this e considerare completato l’issue quando l’errore identifica invece l’incompatibilità della proprietà controvariante.