<p dir="auto">I ran into this error while playing with Rust, it told me to make a bug report:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="src/dynamics/simple_dynamics.rs:52:17: 52:25 error: internal compiler error: debuginfo::create_local_var_metadata() - Referenced variable location is not an alloca!
src/dynamics/simple_dynamics.rs:52             let body_mut = rc::get_mut(body).unwrap();
                                                   ^~~~~~~~
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box&lt;Any&gt;', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/libsyntax/diagnostic.rs:123

stack backtrace:
   1:        0x108c99220 - sys::backtrace::write::hc95aae63c60abfc60Jt
   2:        0x108cb98e7 - failure::on_fail::hc127add6dd357cc5e0z
   3:        0x108c29fda - rt::unwind::begin_unwind_inner::hdbf43425f18437c6FHz
   4:        0x106b34307 - rt::unwind::begin_unwind::h3355969672767655914
   5:        0x106b34294 - diagnostic::SpanHandler::span_bug::hea7ee9aa261e288cr2F
   6:        0x105fbacad - session::Session::span_bug::hdfbd47445f72bab9eVn
   7:        0x10575b51e - middle::pat_util::pat_bindings::closure.49320
   8:        0x106afeb61 - ast_util::walk_pat::h7d3cad2bd4c87dbfTBC
   9:        0x10564a2d0 - trans::controlflow::trans_block::h5d0744ec09805d679Zd
  10:        0x105691c3f - trans::expr::trans_rvalue_stmt_unadjusted::h59279501085e6932y4i
  11:        0x105649b24 - trans::expr::trans_into::h44e9352c5eb030daFGh
  12:        0x10564a4c6 - trans::controlflow::trans_block::h5d0744ec09805d679Zd
  13:        0x105707697 - trans::base::trans_closure::h83ded929acc2e866deu
  14:        0x10563e976 - trans::base::trans_fn::h91abc7c09fbef750upu
  15:        0x10563abac - trans::base::trans_item::h23d355b70575f043AKu
  16:        0x105708dd9 - trans::base::trans_mod::h21384f26cbb919756Pu
  17:        0x10563ad6e - trans::base::trans_item::h23d355b70575f043AKu
  18:        0x105708dd9 - trans::base::trans_mod::h21384f26cbb919756Pu
  19:        0x10563ad6e - trans::base::trans_item::h23d355b70575f043AKu
  20:        0x10570e178 - trans::base::trans_crate::h73c2bbef83961cfeRGv
  21:        0x10540d3bf - driver::phase_4_translate_to_llvm::h50f0f13e625a634f2Ca
  22:        0x1053e5463 - driver::compile_input::h258f407dd8455477wba
  23:        0x105583e5d - thunk::F.Invoke&lt;A,$u{20}R$GT$::invoke::h8883338591471054833
  24:        0x105580770 - rt::unwind::try::try_fn::h8230218938911070377
  25:        0x108d21229 - rust_try_inner
  26:        0x108d21216 - rust_try
  27:        0x105580e6b - thunk::F.Invoke&lt;A,$u{20}R$GT$::invoke::h14505686894590603956
  28:        0x108ca8dc4 - sys::thread::thread_start::h2cb22211a4c7d938vFw
  29:     0x7fff8fb792fc - _pthread_body
  30:     0x7fff8fb79279 - _pthread_body"><pre class="notranslate"><code class="notranslate">src/dynamics/simple_dynamics.rs:52:17: 52:25 error: internal compiler error: debuginfo::create_local_var_metadata() - Referenced variable location is not an alloca!
src/dynamics/simple_dynamics.rs:52             let body_mut = rc::get_mut(body).unwrap();
                                                   ^~~~~~~~
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box&lt;Any&gt;', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/libsyntax/diagnostic.rs:123

stack backtrace:
   1:        0x108c99220 - sys::backtrace::write::hc95aae63c60abfc60Jt
   2:        0x108cb98e7 - failure::on_fail::hc127add6dd357cc5e0z
   3:        0x108c29fda - rt::unwind::begin_unwind_inner::hdbf43425f18437c6FHz
   4:        0x106b34307 - rt::unwind::begin_unwind::h3355969672767655914
   5:        0x106b34294 - diagnostic::SpanHandler::span_bug::hea7ee9aa261e288cr2F
   6:        0x105fbacad - session::Session::span_bug::hdfbd47445f72bab9eVn
   7:        0x10575b51e - middle::pat_util::pat_bindings::closure.49320
   8:        0x106afeb61 - ast_util::walk_pat::h7d3cad2bd4c87dbfTBC
   9:        0x10564a2d0 - trans::controlflow::trans_block::h5d0744ec09805d679Zd
  10:        0x105691c3f - trans::expr::trans_rvalue_stmt_unadjusted::h59279501085e6932y4i
  11:        0x105649b24 - trans::expr::trans_into::h44e9352c5eb030daFGh
  12:        0x10564a4c6 - trans::controlflow::trans_block::h5d0744ec09805d679Zd
  13:        0x105707697 - trans::base::trans_closure::h83ded929acc2e866deu
  14:        0x10563e976 - trans::base::trans_fn::h91abc7c09fbef750upu
  15:        0x10563abac - trans::base::trans_item::h23d355b70575f043AKu
  16:        0x105708dd9 - trans::base::trans_mod::h21384f26cbb919756Pu
  17:        0x10563ad6e - trans::base::trans_item::h23d355b70575f043AKu
  18:        0x105708dd9 - trans::base::trans_mod::h21384f26cbb919756Pu
  19:        0x10563ad6e - trans::base::trans_item::h23d355b70575f043AKu
  20:        0x10570e178 - trans::base::trans_crate::h73c2bbef83961cfeRGv
  21:        0x10540d3bf - driver::phase_4_translate_to_llvm::h50f0f13e625a634f2Ca
  22:        0x1053e5463 - driver::compile_input::h258f407dd8455477wba
  23:        0x105583e5d - thunk::F.Invoke&lt;A,$u{20}R$GT$::invoke::h8883338591471054833
  24:        0x105580770 - rt::unwind::try::try_fn::h8230218938911070377
  25:        0x108d21229 - rust_try_inner
  26:        0x108d21216 - rust_try
  27:        0x105580e6b - thunk::F.Invoke&lt;A,$u{20}R$GT$::invoke::h14505686894590603956
  28:        0x108ca8dc4 - sys::thread::thread_start::h2cb22211a4c7d938vFw
  29:     0x7fff8fb792fc - _pthread_body
  30:     0x7fff8fb79279 - _pthread_body
</code></pre></div>
<p dir="auto">This only happened when I added this line to help me debug:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="panic!(&quot;STRONG REF COUNT: {}&quot;, rc::strong_count(body)); // &lt;- Causes the compiler error
let body_mut = rc::get_mut(body).unwrap();"><pre class="notranslate"><code class="notranslate">panic!("STRONG REF COUNT: {}", rc::strong_count(body)); // &lt;- Causes the compiler error
let body_mut = rc::get_mut(body).unwrap();
</code></pre></div>
<p dir="auto">This is the output from <code class="notranslate">rustc --version --verbose</code>, I am currently on Mac OS X Yosemite:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="rustc 0.13.0-nightly (5ba610265 2014-12-25 18:01:36 +0000)
binary: rustc
commit-hash: 5ba6102657a892457063d2d6a7cbb9632ce282c6
commit-date: 2014-12-25 18:01:36 +0000
host: x86_64-apple-darwin
release: 0.13.0-nightly"><pre class="notranslate"><code class="notranslate">rustc 0.13.0-nightly (5ba610265 2014-12-25 18:01:36 +0000)
binary: rustc
commit-hash: 5ba6102657a892457063d2d6a7cbb9632ce282c6
commit-date: 2014-12-25 18:01:36 +0000
host: x86_64-apple-darwin
release: 0.13.0-nightly
</code></pre></div>
<p dir="auto">This little program causes a compiler panic:</p>
<div class="highlight highlight-source-rust notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="fn main() {
  return;
  let a = &quot;&quot;;
}"><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-k">return</span><span class="pl-kos">;</span>
  <span class="pl-k">let</span> a = <span class="pl-s">""</span><span class="pl-kos">;</span>
<span class="pl-kos">}</span></pre></div>
<p dir="auto">The error message is the following:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="error: internal compiler error: debuginfo::create_local_var_metadata() - Referenced variable location is not an alloca!

thread 'rustc' panicked at 'Box&lt;Any&gt;', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/libsyntax/diagnostic.rs:123

stack backtrace:
   1:        0x1110d3460 - sys::backtrace::write::hd64c72d07de40cf8tbt
   2:        0x1110f3817 - failure::on_fail::h646e1201dbb0ef3bNhz
   3:        0x11106570a - rt::unwind::begin_unwind_inner::hec294e47b94ba78aiZy
   4:        0x10ef6fc57 - rt::unwind::begin_unwind::h558350071601703502
   5:        0x10ef6fbe4 - diagnostic::SpanHandler::span_bug::he3912bc404042fc4LQF
   6:        0x10e40930d - session::Session::span_bug::h5801ed3acd26a48eY4l
   7:        0x10dbbfa8e - middle::pat_util::pat_bindings::closure.48598
   8:        0x10ef3a3f1 - ast_util::walk_pat::hbe1ce29526693031GsC
   9:        0x10daafca0 - trans::controlflow::trans_block::h956d3c669c21aa441Vd
  10:        0x10db6c487 - trans::base::trans_closure::h98002b90cdeb7941jSt
  11:        0x10daa4326 - trans::base::trans_fn::h68450a8b056829a432t
  12:        0x10da9faec - trans::base::trans_item::h8a58a6cf2c6184c8Vnu
  13:        0x10db72f18 - trans::base::trans_crate::h35254e15f256e4f14iv
  14:        0x10d870560 - driver::phase_4_translate_to_llvm::h2943144b3698b013mDa
  15:        0x10d8478b3 - driver::compile_input::hd01e9035001db87cwba
  16:        0x10d9e5d54 - thunk::F.Invoke&lt;A,$u{20}R$GT$::invoke::h356901253070274503
  17:        0x10d9e2670 - rt::unwind::try::try_fn::h13338831715023405046
  18:        0x11115b029 - rust_try_inner
  19:        0x11115b016 - rust_try
  20:        0x10d9e2d6b - thunk::F.Invoke&lt;A,$u{20}R$GT$::invoke::h15972762549593096795
  21:        0x1110e2de4 - sys::thread::thread_start::h719786e0e5fa53d4b1v
  22:     0x7fff8e9742fc - _pthread_body
  23:     0x7fff8e974279 - _pthread_body"><pre class="notranslate"><code class="notranslate">error: internal compiler error: debuginfo::create_local_var_metadata() - Referenced variable location is not an alloca!

thread 'rustc' panicked at 'Box&lt;Any&gt;', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/libsyntax/diagnostic.rs:123

stack backtrace:
   1:        0x1110d3460 - sys::backtrace::write::hd64c72d07de40cf8tbt
   2:        0x1110f3817 - failure::on_fail::h646e1201dbb0ef3bNhz
   3:        0x11106570a - rt::unwind::begin_unwind_inner::hec294e47b94ba78aiZy
   4:        0x10ef6fc57 - rt::unwind::begin_unwind::h558350071601703502
   5:        0x10ef6fbe4 - diagnostic::SpanHandler::span_bug::he3912bc404042fc4LQF
   6:        0x10e40930d - session::Session::span_bug::h5801ed3acd26a48eY4l
   7:        0x10dbbfa8e - middle::pat_util::pat_bindings::closure.48598
   8:        0x10ef3a3f1 - ast_util::walk_pat::hbe1ce29526693031GsC
   9:        0x10daafca0 - trans::controlflow::trans_block::h956d3c669c21aa441Vd
  10:        0x10db6c487 - trans::base::trans_closure::h98002b90cdeb7941jSt
  11:        0x10daa4326 - trans::base::trans_fn::h68450a8b056829a432t
  12:        0x10da9faec - trans::base::trans_item::h8a58a6cf2c6184c8Vnu
  13:        0x10db72f18 - trans::base::trans_crate::h35254e15f256e4f14iv
  14:        0x10d870560 - driver::phase_4_translate_to_llvm::h2943144b3698b013mDa
  15:        0x10d8478b3 - driver::compile_input::hd01e9035001db87cwba
  16:        0x10d9e5d54 - thunk::F.Invoke&lt;A,$u{20}R$GT$::invoke::h356901253070274503
  17:        0x10d9e2670 - rt::unwind::try::try_fn::h13338831715023405046
  18:        0x11115b029 - rust_try_inner
  19:        0x11115b016 - rust_try
  20:        0x10d9e2d6b - thunk::F.Invoke&lt;A,$u{20}R$GT$::invoke::h15972762549593096795
  21:        0x1110e2de4 - sys::thread::thread_start::h719786e0e5fa53d4b1v
  22:     0x7fff8e9742fc - _pthread_body
  23:     0x7fff8e974279 - _pthread_body
</code></pre></div>