Call on OR type rejected without obvious reason.

[dbaeumer]

TypeScript Version: 2.0.2
Code

interface I1 {
    openEditor(input: string, options: string | number): void;
}

interface I2 {
    openEditor(input: string, options: string): void;
}

let part: I1 | I2;

part.openEditor('dirk', 'baeumer');

You get a compile error on part.openEditor. However I think the call should be accepted since the interface could be correctly merged.

[RyanCavanaugh]

Duplicate of #7294

[dbaeumer]

@RyanCavanaugh @mhegazy just wanted to point out that the code above worked in 1.8.10. So in that regard it is not a dup of #7294

[RyanCavanaugh]

There was a change in how we do subtype reduction. The type I1 | I2 is actually somehwat meaningless (I1 is strictly more general) and it was previously reduced immediately to I1, but that had other bad side effects (namely, if you narrow away I1, you'd get neverinstead of I2)