assertion failed: !self.has_escaping_regions()

[elinorbgr]

I was playing around and hit this:

unsafe fn init_array<A, F, T>(mut f: F) -> A
    where F: FnMut() -> T,
          T: 'static,
          for<'a> &'a mut A: ::std::ops::DerefMut<Target=[T]>,
          A: 'static
{
    let mut a: A = std::mem::uninitialized();
    for p in a.iter_mut() {
        std::ptr::write(p, f());
    }
    a
}

fn main() {
    let a: [_; 100] = unsafe { init_array(|| 0u8) };
}

causing

error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'assertion failed: !self.has_escaping_regions()', /var/tmp/portage/dev-lang/rust-9999/work/rust-9999/src/librustc/middle/ty.rs:1932

running with RUST_BACKTRACE=1 simply dies from SIGILL without outputting anything.

rustc --version
rustc 1.0.0-dev (0eb0ba38d 2015-03-01) (built 2015-03-01)

I can reproduce it on the playpen as well, which is a more recent version.

[frewsxcv]

The original code block no longer compiles in Rust 1.0 beta2

~/Downloads $ rustc test.rs
test.rs:8:16: 8:26 error: type `A` does not implement any method in scope named `iter_mut`
test.rs:8     for p in a.iter_mut() {
                         ^~~~~~~~~~
test.rs:8:16: 8:26 help: methods from traits can only be called if the trait is implemented and in scope; the following trait defines a method `iter_mut`, perhaps you need to implement it:
test.rs:8:16: 8:26 help: candidate #1: `core::slice::SliceExt`
test.rs:15:32: 15:42 error: the trait `core::marker::Sized` is not implemented for the type `[_]` [E0277]
test.rs:15     let a: [_; 100] = unsafe { init_array(|| 0u8) };
                                          ^~~~~~~~~~
test.rs:15:32: 15:42 note: `[_]` does not have a constant size known at compile-time
test.rs:15     let a: [_; 100] = unsafe { init_array(|| 0u8) };
                                          ^~~~~~~~~~
test.rs:15:32: 15:50 error: mismatched types:
 expected `[_; 100]`,
    found `[u8]`
(expected array of 100 elements,
    found slice) [E0308]
test.rs:15     let a: [_; 100] = unsafe { init_array(|| 0u8) };
                                          ^~~~~~~~~~~~~~~~~~
error: aborting due to 3 previous errors

~/Downloads $ rustc --version
rustc 1.0.0-beta.2 (e9080ec39 2015-04-16) (built 2015-04-16)