ICE: Generics + Fn + overloaded_calls

[japaric]

STR:

#![feature(overloaded_calls)]

use std::ops::Fn;

struct G;

impl<'a, A: Add<int, int>> Fn<(A,), int> for G {
    extern "rust-call" fn call(&self, (arg,): (A,)) -> int {
        arg.add(&1)
    }
}

fn main() {
    // ICE trigger
    G(1i);
}

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/middle/subst.rs:420

stack backtrace:
   1:     0x7fcce8fb0980 - rt::backtrace::imp::write::h500c7cd49c94d6cbo1q
   2:     0x7fcce8fb3a20 - <unknown>
   3:     0x7fcced528c40 - unwind::begin_unwind_inner::h78b0bc3908c6581cM8d
   4:     0x7fcced528930 - unwind::begin_unwind_fmt::h3b08875489dd9563h6d
   5:     0x7fcced5288f0 - rust_begin_unwind
   6:     0x7fcced566480 - failure::begin_unwind::h97ffd813929e6ce8n5j
   7:     0x7fcced56a120 - failure::fail_bounds_check::h83d6c17dc7061617A3j
   8:     0x7fccedfcb9f0 - middle::trans::common::find_vtable::h3c080be41502d99dym5
   9:     0x7fccedf70e80 - middle::trans::meth::trans_method_callee::h14eb916f1e57823dBYi
  10:     0x7fccedf99fd0 - <unknown>
  11:     0x7fccedf6f2b0 - middle::trans::callee::trans_call_inner::h35fcd3dc6cf92b24QM0
  12:     0x7fccedf999a0 - middle::trans::callee::trans_method_call::hfbb10b0bb60fb1df6H0
  13:     0x7fccedfa7980 - <unknown>
  14:     0x7fccedf65970 - middle::trans::expr::trans_into::h6a75ea5632764d57WG1
  15:     0x7fccedf65f00 - middle::trans::controlflow::trans_block::h4e3ce5bcb386b47byKX
  16:     0x7fccee017fd0 - middle::trans::base::trans_closure::h97b70672122772e4Ffd
  17:     0x7fccedf56d10 - middle::trans::base::trans_fn::h427f2b74d34d9e51rsd
  18:     0x7fccedf57320 - middle::trans::monomorphize::monomorphic_fn::h458ee6f7220bf52aQ6W
  19:     0x7fccedf8eb70 - middle::trans::callee::trans_fn_ref_with_vtables::ha9be7a0f3a6494ac6k0
  20:     0x7fccedf8c3f0 - middle::trans::callee::trans_fn_ref::h04e8c8720c3a684bd6Z
  21:     0x7fccedf70e80 - middle::trans::meth::trans_method_callee::h14eb916f1e57823dBYi
  22:     0x7fccedfc36f0 - <unknown>
  23:     0x7fccedf6f2b0 - middle::trans::callee::trans_call_inner::h35fcd3dc6cf92b24QM0
  24:     0x7fccedfa7980 - <unknown>
  25:     0x7fccedf65970 - middle::trans::expr::trans_into::h6a75ea5632764d57WG1
  26:     0x7fccedf64de0 - middle::trans::controlflow::trans_stmt_semi::h4bd6143bef5cdfaaFJX
  27:     0x7fccedf64510 - middle::trans::controlflow::trans_stmt::he411548830d9db52pFX
  28:     0x7fccedf65f00 - middle::trans::controlflow::trans_block::h4e3ce5bcb386b47byKX
  29:     0x7fccee017fd0 - middle::trans::base::trans_closure::h97b70672122772e4Ffd
  30:     0x7fccedf56d10 - middle::trans::base::trans_fn::h427f2b74d34d9e51rsd
  31:     0x7fccedf51bd0 - middle::trans::base::trans_item::ha5f8c6dffd457508sLd
  32:     0x7fccee024450 - middle::trans::base::trans_crate::hc8a067c8e67c4194ZFe
  33:     0x7fccee4459b0 - driver::driver::phase_4_translate_to_llvm::h0b6bfb0e08d77749xCx
  34:     0x7fccee43cc30 - driver::driver::compile_input::h7879a63579b438beafx
  35:     0x7fccee4e8400 - <unknown>
  36:     0x7fccee4e8310 - <unknown>
  37:     0x7fccee4fac60 - <unknown>
  38:     0x7fccee4faa60 - <unknown>
  39:     0x7fcced883b30 - <unknown>
  40:     0x7fcced578970 - <unknown>
  41:     0x7fcced578960 - rust_try
  42:     0x7fcced5262a0 - unwind::try::h36697dac480a0e50hXd
  43:     0x7fcced526040 - task::Task::run::h0fb2de2c85c53b00T4c
  44:     0x7fcced8838f0 - <unknown>
  45:     0x7fcced527e80 - <unknown>
  46:     0x7fcce832b000 - start_thread
  47:     0x7fcced1f7269 - clone
  48:                0x0 - <unknown>

Version:

rustc 0.12.0-pre (a8c8e3f80 2014-08-14 19:11:18 +0000)

cc @pcwalton

This is an updated version of the snippet posted by @pczarn in #15678. Issue 15678 describes an ICE that occurs during type checking, but this snippet produces a different ICE (during the translation phase), so I have opened this issue to track the second ICE.

[pczarn]

Thanks. I had mistakenly assumed that the type checker is at fault, because I couldn't make it ICE with other combinations of type parameters.