internal compiler error: ident only path should have been covered already

[Hansyperman]

$ cat testje.rs
fn main(){
    let mut v=std::vec::Vec::<isize>::new();
    v.push(1);
    v.push(2);
    // The next line makes rust crash.  It does not make any sense (it was just a typo) but thought i'd report it anyway.
    let v[0]=v[1];
}

$ rustc --version
rustc 1.0.0-nightly (890293655 2015-02-28) (built 2015-03-01)

$ RUST_BACKTRACE=1 rustc testje.rs
testje.rs:6:9: 6:10 error: internal compiler error: ident only path should have been covered already
testje.rs:6     let v[0]=v[1];
                    ^
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 'Box<Any>', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:129

stack backtrace:
   1:         0x577a6c4f - sys::backtrace::write::hb08af03691eab78a5kA
   2:         0x577cf782 - panicking::on_panic::h37164609ca1c02afBnJ
   3:         0x5770f63a - rt::unwind::begin_unwind_inner::h24d5e7492198457b43I
   4:         0x54a55a8d - rt::unwind::begin_unwind::h9113908695753286194
   5:         0x54a55a33 - diagnostic::SpanHandler::span_bug::hcbc27df468564853WBD
   6:         0x54a7b905 - parse::parser::Parser<'a>::parse_pat::hf7a2ebdbbed007b1d3J
   7:         0x54a8df2d - parse::parser::Parser<'a>::parse_local::h7d6c62c9c63efba1xkK
   8:         0x54a8f22f - parse::parser::Parser<'a>::parse_stmt::h622ba475055891c9inK
   9:         0x54a97e89 - parse::parser::Parser<'a>::parse_block_tail_::hb2f43cc30c93d511ryK
  10:         0x54a75dec - parse::parser::Parser<'a>::parse_inner_attrs_and_block::h554d87549b4ccdacTwK
  11:         0x54a9c465 - parse::parser::Parser<'a>::parse_item_fn::hbda705c8fc5a7ac1icL
  12:         0x54a92778 - parse::parser::Parser<'a>::parse_item_::hf9f9cf23aa0f1cd4iaM
  13:         0x54aa2985 - parse::parser::Parser<'a>::parse_mod_items::habe606a27fa5b86dSAL
  14:         0x54aacc6c - parse::parser::Parser<'a>::parse_crate_mod::h8c08698d71a0eba6PAM
  15:         0x54abf61e - parse::parse_crate_from_file::ha077e55f357e36faJNT
  16:         0x57e341b1 - driver::phase_1_parse_input::closure.15399
  17:         0x57e0e7b7 - driver::phase_1_parse_input::h21d9f24721445c1fvqa
  18:         0x57e0b181 - driver::compile_input::hee81c045ab46c74fIba
  19:         0x57ed6e6e - run_compiler::h875c1e123fe4ae2cF5b
  20:         0x57ed4a1c - thunk::F.Invoke<A, R>::invoke::h12424714292252424185
  21:         0x57ed3770 - rt::unwind::try::try_fn::h4021821266450575721
  22:         0x5783afe8 - rust_try_inner
  23:         0x5783afd5 - rust_try
  24:         0x57ed3e5c - thunk::F.Invoke<A, R>::invoke::h8199562432922027576
  25:         0x577bb2d5 - sys::thread::thread_start::h1b1bb1e7ac08d3a6yRE
  26:         0x5150db4f - start_thread
  27:         0x573a270c - <unknown>

There are a few issues with the same error message, but they seem to have been fixed before my nightly - and the way to cause it is also different

[Kimundi]

See #22426