match of associated_const from const_fn

[Johnson-A]

I am using an associated constant in a match pattern. The associated constant was initiated with a const function. https://play.rust-lang.org/?gist=0a3ce02daba0b2226cac&version=nightly

#![feature(associated_consts, const_fn)]
struct A(u32);

impl A {
    const fn new() -> A { A(0) }
    const TEST: A = A::new();
}

fn main() {
    match A(1) {
        A::TEST => (),
        _ => ()
    }
}

I would expect this to work but instead I get a compile error.

Version:
rustc 1.3.0-nightly (4d52d7c 2015-07-30)
binary: rustc
commit-hash: 4d52d7c
commit-date: 2015-07-30
host: x86_64-apple-darwin
release: 1.3.0-nightly

Backtrace:
thread 'rustc' panicked at 'internal error: entered unreachable code', ../src/librustc/middle/const_eval.rs:303

stack backtrace:
1: 0x11045b775 - sys::backtrace::write::h00f40a024c5fc864Ovs
2: 0x11046487e - panicking::on_panic::h0e43a2acb42d44b6wWw
3: 0x11041e342 - rt::unwind::begin_unwind_inner::ha56aa2c668bd1b81HEw
4: 0x10d1d3046 - rt::unwind::begin_unwind::h5600055422857985838
5: 0x10d34d4ec - middle::const_eval::const_expr_to_pat::hb3e6bc475d6b1549byj
6: 0x10d34474f - middle::check_match::StaticInliner<'a, 'tcx>.Folder::fold_pat::h89405171f869c1bdPWh
7: 0x10d3442e5 - iter::Map<I, F>.Iterator::next::h8976116763720396864
8: 0x10d3406c0 - middle::check_match::check_expr::h0dc9e986b4200cebTyh
9: 0x10d3400ae - middle::check_match::check_expr::h0dc9e986b4200cebTyh
10: 0x10d342deb - middle::check_match::check_fn::hb4a13b41d8a3214fUKi
11: 0x10d343da6 - visit::walk_impl_item::h16511485676432689156
12: 0x10d34345e - visit::walk_item::h16706684038497946513
13: 0x10d3431de - visit::walk_item::h16706684038497946513
14: 0x10d342f4a - middle::check_match::check_crate::h6da5404894312007xyh
15: 0x10c8de265 - driver::phase_3_run_analysis_passes::closure.16497
16: 0x10c8daf8c - middle::ty::ctxt<'tcx>::create_and_enter::h15699848509377711113
17: 0x10c8d6066 - driver::phase_3_run_analysis_passes::h8204244616204611716
18: 0x10c8bbf5c - driver::compile_input::h15546a0a04ea3d9bTba
19: 0x10c99f960 - run_compiler::hba01dad9ef72ac1bA7b
20: 0x10c99d3f0 - boxed::F.FnBox::call_box::h17305433943357537886
21: 0x10c99cc67 - rt::unwind::try::try_fn::h14437690116303608274
22: 0x11046432f - __rust_try_inner
23: 0x11046436a - __rust_try
24: 0x11044dd15 - rt::unwind::try::inner_try::h7ac3b4630cf0a4afAAw
25: 0x10c99cea9 - boxed::F.FnBox::call_box::h6665094899717926123
26: 0x11046330d - sys::thread::Thread::new::thread_start::h22fe824ce7ac562bbZv
27: 0x7fff9ad42267 - _pthread_body
28: 0x7fff9ad421e4 - _pthread_start

[apasel422]

Still an issue.

[Mark-Simulacrum]

This no longer ICEs, and I don't think that tracking the unimplemented constant evaluation makes sense--having a specific tracking issue for that won't make it get implemented, it'll come with miri's merge into rustc.