Internal compiler error for summation of different numerical types.

[sparrisable]

Got an internal compiler error for a small simple program.

I tried this code:

fn minutes_to_hours(minutes:isize) -> (f32) {
let mut hours = minutes/60;
let mut decimal_hours = 0.0;
hours = hours +1;
hours + decimal_hours
}

fn main() {}

I expected to see this happen:
To get a compiler error message or a resulting compiled binary from the compiler.

Instead, this happened:

rustc internal_compiler_error.rs
error: internal compiler error: Impl DefId { krate: 2, node: 21469 } was matchable against Obligation(predicate=Binder(TraitPredicate(core::ops::Add<_>)),depth=1) but now is not
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', C:/bot/slave/beta-dist-rustc-win-64/build/src/libsyntax\diagnostic.rs:209

rustc --version --verbose
rustc 1.0.0-beta.5 (7b4ef47 2015-05-11) (built 2015-05-11)
binary: rustc
commit-hash: 7b4ef47
commit-date: 2015-05-11
build-date: 2015-05-11
host: x86_64-pc-windows-gnu
release: 1.0.0-beta.5

Backtrace:
This was on a windows pc and I did not manage to get a backtrace.

[econoplas]

Contributing a backtrace using the OP's code in case it proves useful:

Meta

rustc --version --verbose:
rustc 1.0.0-dev (built 2015-05-13)
binary: rustc
commit-hash: unknown
commit-date: unknown
build-date: 2015-05-13
host: x86_64-unknown-linux-gnu
release: 1.0.0-dev

Backtrace:
thread 'rustc' panicked at 'Box', /tmp/build/rustc-1.0.0-beta.5/src/libsyntax/diagnostic.rs:209

stack backtrace:
1: 0x7fdcb8c10109 - sys::backtrace::write::he573c8167e01081cd4r
2: 0x7fdcb8c17e16 - panicking::on_panic::had2e9609e9ec19cdjrw
3: 0x7fdcb8bdb122 - rt::unwind::begin_unwind_inner::h2b37885f8310bdebt6v
4: 0x7fdcb61a9a9d - rt::unwind::begin_unwind::h9513671965667180055
5: 0x7fdcb61aa15b - diagnostic::Handler::bug::h17f6338c5abd9ad8gwB
6: 0x7fdcb6d41e19 - middle::traits::select::SelectionContext<'cx, 'tcx>::rematch_impl::h0fe197b1312ddfc5QXT
7: 0x7fdcb6d418a8 - middle::infer::InferCtxt<'a, 'tcx>::commit_if_ok::h12728828371683694127
8: 0x7fdcb6d2bee1 - middle::traits::select::SelectionContext<'cx, 'tcx>::confirm_candidate::h1a91ee65f37b548cSfT
9: 0x7fdcb6d0b224 - middle::traits::select::SelectionContext<'cx, 'tcx>::select::h3318be58b29b06ecvhR
10: 0x7fdcb6d16085 - middle::traits::project::project_type::h2299b95043dc8d51CYP
11: 0x7fdcb6d14c68 - middle::traits::project::opt_normalize_projection_type::h0aba98dabe25d81feRP
12: 0x7fdcb6d11980 - middle::traits::project::project_and_unify_type::h71f271abe450dd5b8zP
13: 0x7fdcb6d0fd8c - middle::infer::InferCtxt<'a, 'tcx>::commit_if_ok::h14704270297610222976
14: 0x7fdcb6d083ad - middle::traits::fulfill::FulfillmentContext<'tcx>::select::h4ea72577c16ace0bG9O
15: 0x7fdcb6d07ddb - middle::traits::fulfill::FulfillmentContext<'tcx>::select_where_possible::hcaa2f53ce1ed4358U8O
16: 0x7fdcb79d88e8 - check::vtable::select_fcx_obligations_where_possible::h4a3bbd0f0b1109dar5b
17: 0x7fdcb79f695a - check::FnCtxt<'a, 'tcx>::resolve_type_vars_if_possible::h1d2300a64a85ceaaVwo
18: 0x7fdcb7a57ede - check::op::check_binop::hc37315610f504162XMm
19: 0x7fdcb7a955ed - check::check_expr_with_unifier::h1788505187362938359
20: 0x7fdcb7a65bcc - check::check_block_with_expected::h9b5df56861210b9dnUr
21: 0x7fdcb7a483b6 - check::check_fn::ha41cad12b3ab8b73UGn
22: 0x7fdcb7a61284 - check::check_bare_fn::hf00f4144cb54e3b8twn
23: 0x7fdcb7a5f3e2 - check::CheckItemBodiesVisitor<'a, 'tcx>.Visitor<'tcx>::visit_item::h97632d2c1e4ecd72wtn
24: 0x7fdcb7b2338a - check_crate::closure.38021
25: 0x7fdcb7b1e720 - check_crate::h4a34989eac58b4d7XcC
26: 0x7fdcb9153a38 - driver::phase_3_run_analysis_passes::he8a5e6db549c1a9fnGa
27: 0x7fdcb9134b35 - driver::compile_input::h0028b8480dd1e160Qba
28: 0x7fdcb91f6041 - run_compiler::h3ecadef83df8b674z4b
29: 0x7fdcb91f3c92 - boxed::F.FnBox::call_box::h796248444002942158
30: 0x7fdcb91f31c9 - rt::unwind::try::try_fn::h1722916880066884737
31: 0x7fdcb8c8ac08 - rust_try_inner
32: 0x7fdcb8c8abf5 - rust_try
33: 0x7fdcb91f3478 - boxed::F.FnBox::call_box::h17871347209311949743
34: 0x7fdcb8c16d01 - sys::thread::create::thread_start::h775b7ea1b9caf098aqv
35: 0x7fdcb371edf4 - start_thread
36: 0x7fdcb88601ac - __clone
37: 0x0 -

[arielb1]

Fixed by #25344.

[alexcrichton]

Thanks @arielb1!