<p dir="auto">Found this while refactoring my library after the <code class="notranslate">Vector</code> -&gt; <code class="notranslate">Slice</code> rename</p>
<p dir="auto">STR:</p>
<div class="highlight highlight-source-rust notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="use std::{mem, raw};

fn main() {
    let a = &amp;[1, 2, 3i];
    let raw::Slice { data: ptr, len: len }: raw::Slice&lt;int&gt; = unsafe { mem::transmute(a) };
    let b = unsafe { mem::transmute(Slice { data: ptr, len: len }) };
    // ICE                          ^~~ forgot the `raw::` qualifier
}"><pre class="notranslate"><span class="pl-k">use</span> std<span class="pl-kos">::</span><span class="pl-kos">{</span>mem<span class="pl-kos">,</span> raw<span class="pl-kos">}</span><span class="pl-kos">;</span>

<span class="pl-k">fn</span> <span class="pl-en">main</span><span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-kos">{</span>
    <span class="pl-k">let</span> a = <span class="pl-c1">&amp;</span><span class="pl-kos">[</span><span class="pl-c1">1</span><span class="pl-kos">,</span> <span class="pl-c1">2</span><span class="pl-kos">,</span> <span class="pl-c1">3</span>i<span class="pl-kos">]</span><span class="pl-kos">;</span>
    <span class="pl-k">let</span> raw<span class="pl-kos">::</span><span class="pl-v">Slice</span> <span class="pl-kos">{</span> <span class="pl-c1">data</span><span class="pl-kos">:</span> ptr<span class="pl-kos">,</span> <span class="pl-c1">len</span><span class="pl-kos">:</span> len <span class="pl-kos">}</span><span class="pl-kos">:</span> raw<span class="pl-kos">::</span><span class="pl-smi">Slice</span><span class="pl-kos">&lt;</span><span class="pl-smi">int</span><span class="pl-kos">&gt;</span> = <span class="pl-k">unsafe</span> <span class="pl-kos">{</span> mem<span class="pl-kos">::</span><span class="pl-en">transmute</span><span class="pl-kos">(</span>a<span class="pl-kos">)</span> <span class="pl-kos">}</span><span class="pl-kos">;</span>
    <span class="pl-k">let</span> b = <span class="pl-k">unsafe</span> <span class="pl-kos">{</span> mem<span class="pl-kos">::</span><span class="pl-en">transmute</span><span class="pl-kos">(</span><span class="pl-smi">Slice</span> <span class="pl-kos">{</span> <span class="pl-c1">data</span><span class="pl-kos">:</span> ptr<span class="pl-kos">,</span> <span class="pl-c1">len</span><span class="pl-kos">:</span> len <span class="pl-kos">}</span><span class="pl-kos">)</span> <span class="pl-kos">}</span><span class="pl-kos">;</span>
    <span class="pl-c">// ICE                          ^~~ forgot the `raw::` qualifier</span>
<span class="pl-kos">}</span></pre></div>
<p dir="auto">Backtrace:</p>
<div class="highlight highlight-source-rust notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="task 'rustc' failed at 'explicit failure', /var/tmp/paludis/build/dev-lang-rust-scm/work/rust-scm/src/librbml/lib.rs:246

stack backtrace:
   1:     0x7fadbcf65980 - rt::backtrace::imp::write::h500c7cd49c94d6cbo1q
   2:     0x7fadbcf68a20 - &lt;unknown&gt;
   3:     0x7fadc14ddc40 - unwind::begin_unwind_inner::h78b0bc3908c6581cM8d
   4:     0x7fadc03d5310 - &lt;unknown&gt;
   5:     0x7fadc03d4340 - reader::get_doc::h659c9cb63ec6b27dQRa
   6:     0x7fadc23b9d40 - metadata::decoder::get_type::h8aa840f508fceb99Bis
   7:     0x7fadc1df73b0 - middle::ty::lookup_item_type::h0762f54f39bdc9b9J5G
   8:     0x7fadc2154ec0 - &lt;unknown&gt;
   9:     0x7fadc2152820 - &lt;unknown&gt;
  10:     0x7fadc2154ec0 - &lt;unknown&gt;
  11:     0x7fadc211dba0 - &lt;unknown&gt;
  12:     0x7fadc2154ec0 - &lt;unknown&gt;
  13:     0x7fadc21b39c0 - middle::typeck::check::check_decl_local::h2a1925bfb9a5b157XEW
  14:     0x7fadc21b3be0 - middle::typeck::check::check_stmt::he6d6f56b73c868b94GW
  15:     0x7fadc211dba0 - &lt;unknown&gt;
  16:     0x7fadc2119930 - &lt;unknown&gt;
  17:     0x7fadc2119650 - &lt;unknown&gt;
  18:     0x7fadc2112510 - middle::typeck::check::check_item::h9d5462bdf5870d8fxhS
  19:     0x7fadc2119450 - middle::typeck::check::check_item_types::h60cfbf824eb42ae21HR
  20:     0x7fadc1b2a150 - &lt;unknown&gt;
  21:     0x7fadc23275c0 - middle::typeck::check_crate::h322ddeef25afc167p2i
  22:     0x7fadc23f6af0 - driver::driver::phase_3_run_analysis_passes::h01e8a18355fa9e80Vsx
  23:     0x7fadc23f1c30 - driver::driver::compile_input::h7879a63579b438beafx
  24:     0x7fadc249d400 - &lt;unknown&gt;
  25:     0x7fadc249d310 - &lt;unknown&gt;
  26:     0x7fadc24afc60 - &lt;unknown&gt;
  27:     0x7fadc24afa60 - &lt;unknown&gt;
  28:     0x7fadc1838b30 - &lt;unknown&gt;
  29:     0x7fadc152d970 - &lt;unknown&gt;
  30:     0x7fadc152d960 - rust_try
  31:     0x7fadc14db2a0 - unwind::try::h36697dac480a0e50hXd
  32:     0x7fadc14db040 - task::Task::run::h0fb2de2c85c53b00T4c
  33:     0x7fadc18388f0 - &lt;unknown&gt;
  34:     0x7fadc14dce80 - &lt;unknown&gt;
  35:     0x7fadbc2e0000 - start_thread
  36:     0x7fadc11ac269 - clone
  37:                0x0 - &lt;unknown&gt;"><pre class="notranslate">task <span class="pl-c1">'</span>rustc<span class="pl-c1">'</span> failed at <span class="pl-c1">'</span>explicit failure<span class="pl-c1">'</span><span class="pl-kos">,</span> /var/tmp/paludis/build/dev-lang-rust-scm/work/rust-scm/src/librbml/lib<span class="pl-kos">.</span><span class="pl-c1">rs</span><span class="pl-kos">:</span><span class="pl-c1">246</span>

stack backtrace<span class="pl-kos">:</span>
   <span class="pl-c1">1</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadbcf65980</span> - rt<span class="pl-kos">::</span>backtrace<span class="pl-kos">::</span>imp<span class="pl-kos">::</span>write<span class="pl-kos">::</span>h500c7cd49c94d6cbo1q
   <span class="pl-c1">2</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadbcf68a20</span> - &lt;<span class="pl-smi">unknown</span>&gt;
   <span class="pl-c1">3</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc14ddc40</span> - unwind<span class="pl-kos">::</span>begin_unwind_inner<span class="pl-kos">::</span>h78b0bc3908c6581cM8d
   <span class="pl-c1">4</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc03d5310</span> - &lt;<span class="pl-smi">unknown</span>&gt;
   <span class="pl-c1">5</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc03d4340</span> - reader<span class="pl-kos">::</span>get_doc<span class="pl-kos">::</span>h659c9cb63ec6b27dQRa
   <span class="pl-c1">6</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc23b9d40</span> - metadata<span class="pl-kos">::</span>decoder<span class="pl-kos">::</span>get_type<span class="pl-kos">::</span>h8aa840f508fceb99Bis
   <span class="pl-c1">7</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc1df73b0</span> - middle<span class="pl-kos">::</span>ty<span class="pl-kos">::</span>lookup_item_type<span class="pl-kos">::</span>h0762f54f39bdc9b9J5G
   <span class="pl-c1">8</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc2154ec0</span> - &lt;<span class="pl-smi">unknown</span>&gt;
   <span class="pl-c1">9</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc2152820</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">10</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc2154ec0</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">11</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc211dba0</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">12</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc2154ec0</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">13</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc21b39c0</span> - middle<span class="pl-kos">::</span>typeck<span class="pl-kos">::</span>check<span class="pl-kos">::</span>check_decl_local<span class="pl-kos">::</span>h2a1925bfb9a5b157XEW
  <span class="pl-c1">14</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc21b3be0</span> - middle<span class="pl-kos">::</span>typeck<span class="pl-kos">::</span>check<span class="pl-kos">::</span>check_stmt<span class="pl-kos">::</span>he6d6f56b73c868b94GW
  <span class="pl-c1">15</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc211dba0</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">16</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc2119930</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">17</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc2119650</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">18</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc2112510</span> - middle<span class="pl-kos">::</span>typeck<span class="pl-kos">::</span>check<span class="pl-kos">::</span>check_item<span class="pl-kos">::</span>h9d5462bdf5870d8fxhS
  <span class="pl-c1">19</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc2119450</span> - middle<span class="pl-kos">::</span>typeck<span class="pl-kos">::</span>check<span class="pl-kos">::</span>check_item_types<span class="pl-kos">::</span>h60cfbf824eb42ae21HR
  <span class="pl-c1">20</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc1b2a150</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">21</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc23275c0</span> - middle<span class="pl-kos">::</span>typeck<span class="pl-kos">::</span>check_crate<span class="pl-kos">::</span>h322ddeef25afc167p2i
  <span class="pl-c1">22</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc23f6af0</span> - driver<span class="pl-kos">::</span>driver<span class="pl-kos">::</span>phase_3_run_analysis_passes<span class="pl-kos">::</span>h01e8a18355fa9e80Vsx
  <span class="pl-c1">23</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc23f1c30</span> - driver<span class="pl-kos">::</span>driver<span class="pl-kos">::</span>compile_input<span class="pl-kos">::</span>h7879a63579b438beafx
  <span class="pl-c1">24</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc249d400</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">25</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc249d310</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">26</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc24afc60</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">27</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc24afa60</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">28</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc1838b30</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">29</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc152d970</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">30</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc152d960</span> - rust_try
  <span class="pl-c1">31</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc14db2a0</span> - unwind<span class="pl-kos">::</span>try<span class="pl-kos">::</span>h36697dac480a0e50hXd
  <span class="pl-c1">32</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc14db040</span> - task<span class="pl-kos">::</span><span class="pl-smi">Task</span><span class="pl-kos">::</span>run<span class="pl-kos">::</span>h0fb2de2c85c53b00T4c
  <span class="pl-c1">33</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc18388f0</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">34</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc14dce80</span> - &lt;<span class="pl-smi">unknown</span>&gt;
  <span class="pl-c1">35</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadbc2e0000</span> - start_thread
  <span class="pl-c1">36</span><span class="pl-kos">:</span>     <span class="pl-c1">0x7fadc11ac269</span> - clone
  <span class="pl-c1">37</span><span class="pl-kos">:</span>                <span class="pl-c1">0x0</span> - &lt;<span class="pl-smi">unknown</span>&gt;</pre></div>
<p dir="auto">Version:</p>
<div class="highlight highlight-source-rust notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="rustc 0.12.0-pre (a8c8e3f80 2014-08-14 19:11:18 +0000)"><pre class="notranslate">rustc <span class="pl-c1">0.12</span><span class="pl-kos">.</span><span class="pl-c1">0</span>-<span class="pl-en">pre</span> <span class="pl-kos">(</span>a8c8e3f80 <span class="pl-c1">2014</span>-<span class="pl-c1">08</span>-<span class="pl-c1">14</span> <span class="pl-c1">19</span><span class="pl-kos">:</span><span class="pl-c1">11</span><span class="pl-kos">:</span><span class="pl-c1">18</span> +<span class="pl-c1">0000</span><span class="pl-kos">)</span></pre></div>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="failed to find block with tag 7
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_LOG=std::rt::backtrace` for a backtrace
task 'rustc' failed at 'explicit failure', /usr/local/git/rust/src/libserialize/ebml.rs:209"><pre class="notranslate"><code class="notranslate">failed to find block with tag 7
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_LOG=std::rt::backtrace` for a backtrace
task 'rustc' failed at 'explicit failure', /usr/local/git/rust/src/libserialize/ebml.rs:209
</code></pre></div>
<p dir="auto">The following simple code triggers this:</p>
<div class="highlight highlight-source-rust notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="fn main() {
    println!(&quot;{}&quot;, ::std::num::Float::to_radians(200));
}"><pre class="notranslate"><span class="pl-k">fn</span> <span class="pl-en">main</span><span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-kos">{</span>
    <span class="pl-en">println</span><span class="pl-en">!</span><span class="pl-kos">(</span><span class="pl-s">"{}"</span>, ::std::num::<span class="pl-v">Float</span>::to_radians<span class="pl-kos">(</span><span class="pl-c1">200</span><span class="pl-kos">)</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
<span class="pl-kos">}</span></pre></div>