Partial not properly inferred from generic types

[fongandrew]

TypeScript Version: 2.1.4

function test1<O>(): Partial<O> {
  return {};
}

function test2<O extends Object>(): Partial<O> {
  return {};
}

function test3<O extends {}>(): Partial<O> {
  return {};
}

Expected behavior:

No errors.

Actual behavior:

Type '{}' is not assignable to type 'Partial<O>'.

---

Since Partial makes every property optional, we should expect {} to be assignable to every Partial<O>, regardless of what the generic type O is.

Random speculation: Is this intended behavior because O could include required properties on its prototype that aren't on {}, even if all of the properties on O itself are optional? If that's the case, is there a way to specify that we don't care about the prototype's properties?

[TomerKr]

I think this should be changed to a bug rather than a suggestion, as you could expect this work in cases such as the above linked issues.

[RyanCavanaugh]

These work as expected now