Compiler error

[withoutboats]

While updating some of my code to compile under the new updates to rust-nightly, I caused the compiler to panic. Here is the output of rustc -v:

src/lib.rs:420:1: 434:2 error: internal compiler error: impl VtableImpl(impl_def_id=DefId { krate: 0, node: 2045 }:Items<'a, T>.Iterator, substs=Substs[types=[[_];[];[]], regions=[['_#0r];[];[]]], nested=[[Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::kinds::Sized))),depth=1)];[];[]]) did not contain projection for Obligation(predicate=<Items<'a, T> as TraitRef(Items<'a, T>, core::iter::Iterator)>::Item,depth=0)
src/lib.rs:420 impl<'a, T> Iterator for Items<'a, T> {
src/lib.rs:421 #[inline]
src/lib.rs:422 fn next(&mut self) -> Option<&'a T> {
src/lib.rs:423 if self.tail + self.gtail - self.ghead == self.buff.len() { return None };
src/lib.rs:424 let tail = get_idx(self.tail, self.gtail - self.ghead, self.ghead);
src/lib.rs:425 self.tail += 1;
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with RUST_BACKTRACE=1 for a backtrace
thread 'rustc' panicked at 'Box', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:123

[oakes]

Possible duplicate of #20347

[huonw]

Looks like a dupe; thanks for filing!

In this case the fix is writing type Item = &'a T; in the body of the impl.