ICE - importing a module twice, once via glob

[shepmaster]

This only appears to occur in nightly (1.2.0-dev). The playpen has no issues for stable or beta.

Reproduction

use std::{fmt,io};
use std::fmt;

fn main() {}

Output

ice.rs:2:5: 2:13 error: a type named `fmt` has already been imported in this module [E0252]
ice.rs:2 use std::fmt;
             ^~~~~~~~
ice.rs:2:5: 2:13 help: run `rustc --explain E0252` to see a detailed explanation
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 'expected item, found unknown node (id=5)', /Users/shep/Projects/rust/src/libsyntax/ast_map/mod.rs:332

stack backtrace:
   1:        0x10589c26f - sys::backtrace::write::h2bca3a61c3b55d9872r
   2:        0x1058a4dd0 - panicking::on_panic::h3e9ef2bf8e418f81Ijw
   3:        0x10585fba5 - rt::unwind::begin_unwind_inner::he821e5a533856e07r1v
   4:        0x1058609ac - rt::unwind::begin_unwind_fmt::hed0215f4ac0fdeeax0v
   5:        0x104f96452 - ast_map::Map<'ast>::expect_item::h0e10eee0bfdfe3caiGw
   6:        0x10284d673 - resolve_imports::ImportResolver<'a, 'b, 'tcx>::check_for_conflicting_import::hfebb0cf79e3285c8G4c
   7:        0x10284cce2 - resolve_imports::ImportResolver<'a, 'b, 'tcx>::resolve_single_import::closure.15495
   8:        0x1028493e8 - resolve_imports::ImportResolver<'a, 'b, 'tcx>::resolve_import_for_module::h812ee6d1353ff329xdc
   9:        0x102845a27 - resolve_imports::ImportResolver<'a, 'b, 'tcx>::resolve_imports_for_module_subtree::hf772a7c4e28562c9c6b
  10:        0x10288d654 - resolve_crate::h73409eb0503c32dfQai
  11:        0x10231573b - driver::phase_3_run_analysis_passes::h3588a3054907dc71tGa
  12:        0x1022fbb93 - driver::compile_input::h2d12543cc8aeb021Qba
  13:        0x1023b7073 - run_compiler::h933db40d755b0670b6b
  14:        0x1023b47da - boxed::F.FnBox<A>::call_box::h5310392069810752828
  15:        0x1023b3ed7 - rt::unwind::try::try_fn::h18400641036802977081
  16:        0x10592fcc8 - rust_try_inner
  17:        0x10592fcb5 - rust_try
  18:        0x10588ef65 - rt::unwind::try::inner_try::h546a6a033a0ae675kXv
  19:        0x1023b4155 - boxed::F.FnBox<A>::call_box::h1752658228916803127
  20:        0x1058a38dd - sys::thread::Thread::new::thread_start::hc24337cebd0dd75aXlv
  21:     0x7fff93567267 - _pthread_body
  22:     0x7fff935671e4 - _pthread_start

Meta

rustc 1.2.0-dev (c3d60aba6 2015-05-21) (built 2015-05-21)
binary: rustc
commit-hash: c3d60aba6c86883c79055c1a3923d4db116b644e
commit-date: 2015-05-21
build-date: 2015-05-21
host: x86_64-apple-darwin
release: 1.2.0-dev