ICE: Unnamed argument in static trait methods

[japaric]

Script to reproduce:

trait Foo {
    // Good
    fn foo(&self);

    // Good
    fn bar(u8);

    // Good
    fn baz(&self) {

    }

    // ICE
    fn quux(u8) {

    }
}

fn main() {

}

Backtrace:

error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug.
note: we would appreciate a bug report: http://static.rust-lang.org/doc/master/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
task 'rustc' failed at 'index out of bounds: the len is 0 but the index is 0', /var/tmp/paludis/build/dev-lang-rust-scm/work/rust-scm/src/librustc/lib.rs:1
stack backtrace:
   1:     0x7f6efa750b10 - rt::backtrace::imp::write::h1f99132f1b25f9a8lFb::v0.10.pre
   2:     0x7f6efa6b6470 - rt::unwind::begin_unwind_inner::h28090bbbfb0f2ea0Pfb::v0.10.pre
   3:     0x7f6efa6b63e0 - <unknown>
   4:     0x7f6efa750720 - rt::unwind::begin_unwind_raw::h906c42b0deb418a2Ycb::v0.10.pre
   5:     0x7f6efa6b5710 - rt::unwind::fail_::h15821e2ce08a2f70Cab::v0.10.pre
   6:     0x7f6efa750790 - <unknown>
   7:     0x7f6efa6b7670 - rt::unwind::fail_bounds_check::h970f59b4b39b895fZab::v0.10.pre
   8:     0x7f6efb759bb0 - middle::lint::Context$LT$$x27a$GT$.Visitor$LT$$LP$$RP$$GT$::visit_pat::h29763ab81fc19be276B::v0.10.pre
   9:     0x7f6efb75c570 - <unknown>
  10:     0x7f6efb75c4f0 - <unknown>
  11:     0x7f6efb75c6a0 - <unknown>
  12:     0x7f6efb741bb0 - <unknown>
  13:     0x7f6efb759070 - middle::lint::Context$LT$$x27a$GT$.Visitor$LT$$LP$$RP$$GT$::visit_fn::h834b5aee3f3b9929Z9B::v0.10.pre
  14:     0x7f6efb751630 - <unknown>
  15:     0x7f6efb741bb0 - <unknown>
  16:     0x7f6efb759210 - <unknown>
  17:     0x7f6efb7630a0 - <unknown>
  18:     0x7f6efb741bb0 - <unknown>
  19:     0x7f6efb762840 - middle::lint::check_crate::h96b37a495c4c9217hgC::v0.10.pre
  20:     0x7f6efb714200 - <unknown>
  21:     0x7f6efba74ca0 - driver::driver::phase_3_run_analysis_passes::hf88707dd4832a5b5QQe::v0.10.pre
  22:     0x7f6efba7b6a0 - driver::driver::compile_input::h1a4650f2f4c6ec96Nff::v0.10.pre
  23:     0x7f6efba9f360 - run_compiler::h56f03ac7e633fb534Sm::v0.10.pre
  24:     0x7f6efbab2600 - <unknown>
  25:     0x7f6efbab0f30 - <unknown>
  26:     0x7f6efbaac900 - <unknown>
  27:     0x7f6efaddf760 - <unknown>
  28:     0x7f6efa74c230 - <unknown>
  29:     0x7f6efa7575f0 - rust_try
  30:     0x7f6efa74c070 - rt::task::Task::run::h4ac4ccd9ba02c478U48::v0.10.pre
  31:     0x7f6efaddf500 - <unknown>
  32:     0x7f6efa74f5d0 - <unknown>
  33:     0x7f6ef7cdfe30 - <unknown>
  34:     0x7f6efa380a99 - __clone
  35:                0x0 - <unknown>

Exit code: 101

Version:

rustc 0.10-pre (1cd0a5e 2014-03-23 06:06:54 -0700)
host: x86_64-unknown-linux-gnu

[Aatch]

nice catch, looks like a bug in the uppercase_variables lint.

[DaGenix]

I wrote that lint and didn't realize that it was legal to have unnamed function arguments. Whoops.

What is the point of an unnamed function argument? It doesn't seem like you'll be able to do anything with it.

[tomjakubowski]

I can get an ICE even for unnamed arguments in 'non-static' methods:

#![crate_type="lib"]

trait Times {
    fn times(&self, int) {

    }
}

error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug.
note: we would appreciate a bug report: http://static.rust-lang.org/doc/master/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
task 'rustc' failed at 'index out of bounds: the len is 0 but the index is 0', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/librustc/lib.rs:1
stack backtrace:
   1:        0x10fcc9654 - rt::backtrace::imp::write::hf792c9a431d98150WEa::v0.11.pre
   2:        0x10fc2b58e - rt::unwind::begin_unwind_inner::hd86b006519df9a922ea::v0.11.pre
   3:        0x10fc2ad18 - rt::unwind::begin_unwind::h10174172393206223895::v0.11.pre
   4:        0x10fcc9119 - rt::unwind::begin_unwind_raw::hca7322628e40a5b5bca::v0.11.pre
   5:        0x10fc29f8e - rt::unwind::fail_::h7f000d2154e6cd34P99::v0.11.pre
   6:        0x10fcc9162 - rt::unwind::fail_bounds_check::closure.40249
   7:        0x10fc2c09e - rt::unwind::fail_bounds_check::h2ea0b1a4f61a3302caa::v0.11.pre
   8:        0x10d41d9e3 - middle::lint::Context<'a>.Visitor<(*>::visit_pat::h1dc0d8536dedb86a98B::v0.11.pre
   9:        0x10d423f4f - visit::walk_fn::h5356099215230029470::v0.11.pre
  10:        0x10d423ed0 - middle::lint::Context<'a>.Visitor<(*>::visit_fn::closure.70610
  11:        0x10d42435e - middle::lint::Context<'a>.Visitor<(*>::visit_fn::closure.70612
  12:        0x10d403f31 - middle::lint::Context<'a>::with_lint_attrs::hef3c7739e0013001mSA::v0.11.pre
  13:        0x10d41cac0 - middle::lint::Context<'a>.Visitor<(*>::visit_fn::h43414315bc8a5a061bC::v0.11.pre
  14:        0x10d415f1b - middle::lint::Context<'a>.Visitor<(*>::visit_item::closure.70596
  15:        0x10d403f31 - middle::lint::Context<'a>::with_lint_attrs::hef3c7739e0013001mSA::v0.11.pre
  16:        0x10d41cc76 - visit::Visitor::visit_mod::h12750473236215063983::v0.11.pre
  17:        0x10d42a8b7 - middle::lint::check_crate::closure.70667
  18:        0x10d403f31 - middle::lint::Context<'a>::with_lint_attrs::hef3c7739e0013001mSA::v0.11.pre
  19:        0x10d429f05 - middle::lint::check_crate::hdeb4e388e38f57d5jiC::v0.11.pre
  20:        0x10d3d680f - util::common::time::h6685874155479263413::v0.11.pre
  21:        0x10d7f19b1 - driver::driver::phase_3_run_analysis_passes::he6c312d7dc672e1cg1e::v0.11.pre
  22:        0x10d7f6db2 - driver::driver::compile_input::h5cc16b6b358a89603qf::v0.11.pre
  23:        0x10d81cba2 - run_compiler::hfaca67788353830ezUm::v0.11.pre
  24:        0x10d830a1d - main_args::closure.91224
  25:        0x10d82edb2 - monitor::closure.91099
  26:        0x10d82a8fb - task::TaskBuilder::try::closure.90865
  27:        0x10cfd848c - task::spawn_opts::closure.7106
  28:        0x10fcc4758 - rt::task::Task::run::closure.40146
  29:        0x10fcce4cc - rust_try
  30:        0x10fcc45d7 - rt::task::Task::run::h767d3727f94ffe61C57::v0.11.pre
  31:        0x10cfd830f - task::spawn_opts::closure.7078
  32:        0x10fcc8026 - rt::thread::thread_start::h6bde74cf5aa3b556PK8::v0.11.pre
  33:     0x7fff86d8b899 - _pthread_body
  34:     0x7fff86d8b72a - _pthread_struct_init