Inconsistency in types returned by Object.assign

[bjouhier]

TypeScript Version: 2.1.5

Code

const foo = Object.assign({}, {
    f() { return 1; }
});
// next line does not give error because foo is typed as any :-(
foo.g();

const bar = {
    f() { return 1; }
}
const zoo = Object.assign({}, bar);
// but next line does give error :-)
zoo.h();

Expected behavior:
foo.ts(5,5): error TS2339: Property 'g' does not exist on type '{} & { f(): number; }'.
foo.ts(12,5): error TS2339: Property 'h' does not exist on type '{} & { f(): number; }'.

Actual behavior:
foo.ts(12,5): error TS2339: Property 'h' does not exist on type '{} & { f(): number; }'.

[mhegazy]

Though not the same issue, but should be covered by #11100

[RyanCavanaugh]

This has been fixed