ICE with assert! misusage

[youknowone]

rust version: edae0bdabf75b6acf4f0f0eb5bc2bd3b29d58b81

minimal case:

#![feature(macro_rules)]










pub fn main() {
    assert!('a', 'x');
}

error session:

$ RUST_BACKTRACE=1 rustc bug.rs
<std macros>:8:12: 13:16 error: cannot apply unary operator `!` to type `char`
<std macros>:8         if !$cond {
<std macros>:9             fail!($($arg),+)
<std macros>:10         }
<std macros>:11     );
<std macros>:12 )
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 12 but the index is 12', /Users/youknowone/Projects/rust/src/libsyntax/lib.rs:1
stack backtrace:
   1:        0x10fcd66d5 - rt::backtrace::imp::write::h323721627b2b1225X7F::v0.11.pre
   2:        0x10fc4288d - rt::unwind::begin_unwind_inner::h60760c64743357011HF::v0.11.pre
   3:        0x10fcd6180 - rt::unwind::begin_unwind::h6020163020384298928::v0.11.pre
   4:        0x10fcd60cd - rust_fail_bounds_check
   5:        0x10fce82de - failure::fail_bounds_check::h7f0a2bd1d0f5f720IuF::v0.11.pre
   6:        0x10f311589 - codemap::FileMap::get_line::h9336c90a9f16f513Crd::v0.11.pre
   7:        0x10f30e7b6 - diagnostic::emit::h959dada577311038Igc::v0.11.pre
   8:        0x10f306348 - diagnostic::EmitterWriter.Emitter::emit::h3237aef84ed976e5Pcc::v0.11.pre
   9:        0x10f3032b4 - diagnostic::Handler::emit::h8571242cc72ee46cU0b::v0.11.pre
  10:        0x10f3021e1 - diagnostic::SpanHandler::span_err::h5d7dc5dae491f8232Sb::v0.11.pre
  11:        0x10d18f720 - middle::typeck::infer::InferCtxt<'a>::type_error_message_str_with_expected::hb3ac5fd44a2425f9HJq::v0.11.pre
  12:        0x10d22ce5a - middle::typeck::infer::InferCtxt<'a>::type_error_message::hb39509a45c2ca49dpRq::v0.11.pre
  13:        0x10d23b06a - middle::typeck::check::check_expr_with_unifier::check_user_unop::closure.69252
  14:        0x10d238b91 - middle::typeck::check::check_expr_with_unifier::lookup_op_method::hda7bc63cc77f2cb5Yhb::v0.11.pre
  15:        0x10d23ae30 - middle::typeck::check::check_expr_with_unifier::check_user_unop::h2c5b8ba19a387c68Qwb::v0.11.pre
  16:        0x10d234e0d - middle::typeck::check::check_expr_with_unifier::hda4aceb5d627d37dDIa::v0.11.pre
  17:        0x10d22f7b2 - middle::typeck::check::check_expr_with_unifier::hda4aceb5d627d37dDIa::v0.11.pre
  18:        0x10d24a6f3 - middle::typeck::check::check_stmt::h3ef4296b6235d3a5F3c::v0.11.pre
  19:        0x10d20e98a - middle::typeck::check::check_block_with_expected::h38d53dd50936aaf9C7c::v0.11.pre
  20:        0x10d20a17a - middle::typeck::check::check_fn::h6e445ad5ae361babHv8::v0.11.pre
  21:        0x10d20999a - middle::typeck::check::check_bare_fn::h04b771654cb10f90el8::v0.11.pre
  22:        0x10d2018cf - middle::typeck::check::check_item::he9ac829b3c2e5150iS8::v0.11.pre
  23:        0x10d20971d - middle::typeck::check::check_item_types::h10914accf6220219wk8::v0.11.pre
  24:        0x10d3490e6 - util::common::time::h16118557760602876446::v0.11.pre
  25:        0x10d34811d - middle::typeck::check_crate::h2ec4c444fa31334a8gw::v0.11.pre
  26:        0x10d70a36d - driver::driver::phase_3_run_analysis_passes::h921ebf4905d02d63Wci::v0.11.pre
  27:        0x10d703b33 - driver::driver::compile_input::hea625012341a5a6dt2h::v0.11.pre
  28:        0x10d7a12dd - driver::main_args::closure.92564
  29:        0x10d7b52a7 - driver::monitor::closure.93739
  30:        0x10d7afaab - task::TaskBuilder::try::closure.93506
  31:        0x10cf0178c - task::spawn_opts::closure.7440
  32:        0x10fccd3e8 - rt::task::Task::run::closure.28473
  33:        0x10fceefec - rust_try
  34:        0x10fccd267 - rt::task::Task::run::h5ae656a629cc94b6gxD::v0.11.pre
  35:        0x10cf015ef - task::spawn_opts::closure.7412
  36:        0x10fcd4f06 - rt::thread::thread_start::hea60fb28b6673887rfE::v0.11.pre
  37:     0x7fff870d6899 - _pthread_body
  38:     0x7fff870d672a - _pthread_struct_init

required condition:

• mistyped usage in assert! - any 2 char type arguments make this error
• specific lines before assert! code - if you remove blank lines, it start working correctly

I have no idea to reduce this code anymore.

[huonw]

Thanks for filing but this is a dupe of #14091. (These whitespace bugs are weird!)