strict function argument types

[ccorcos]

TypeScript Version: 2.5.3

Code

interface X {
	x: number
}

interface Y {
	x: number
	y: number
}


function f(x: Y) { }

const g : (x: X) => void = f

Expected behavior:

I would expect g to have an error because f can get called without the necessary y property...

Actual behavior:

...but there isnt.

[ahejlsberg]

See #18654.

[ccorcos]

awesome! thanks. is this coming out with 2.6 or 2.7?

[ahejlsberg]

It's in the 2.6 release.

https://blogs.msdn.microsoft.com/typescript/2017/10/12/announcing-typescript-2-6-rc/