mozilla/rust — pull request #14859 by pcwalton (2014-06-12 23:31:31+00:00)
Title: librustc: Forbid `transmute` from being called on types whose size is

only known post-monomorphization, and report `transmute` errors before
the code is generated for that `transmute`.

This can break code that looked like:

unsafe fn f(x: T) {
let y: int = transmute(x);
}

Change such code to take a type parameter that has the same size as the
type being transmuted to.

Closes #12898.

[breaking-change]

r? @alexcrichton