Generics with 'extends' for return types cause type check failure.

[na-o-ys]

TypeScript Version: 2.2.0

Code

interface I { attr: string }

type M = <T extends I>() => T
const v: M = () => ({})

v().attr

Expected behavior:

Type '() => {}' is not assignable to type 'M'. Type '{}' is not assignable to type 'I'.

Actual behavior:

The compilation is successful.

[zpdDG4gta8XKpMCd]

@RyanCavanaugh is there any chance to fix assignability checks for generic and do it properly? not sure which issue tracks it (there are way to many)

[ahejlsberg]

Fixed by #16368.