Remove `T: Sized` on pointer `as_ref()` and `as_mut()`#44932

Merged

bors merged 5 commits intorust-lang:masterfrom

cuviper:unsized-ptr-is_null

Nov 7, 2017

Commits on Sep 29, 2017

Commits on Sep 30, 2017

Use unsized coercions for null ptr tests
cuviper
committed

Commits on Oct 10, 2017

Restore `T: Sized` on `ptr::is_null`
cuviper
committed