<p dir="auto">When trying to compile the following code snippet from the project rust-efl:</p>
<div class="highlight highlight-source-rust notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="impl&lt;'r, T&gt; Iterator for EinaList&lt;'r, T&gt; {
    fn next(&amp;mut self) -&gt; Option&lt;&amp;'r T&gt; {
        let v = list_data_get(self._eo);
        *self = match list_next(self._eo) {
            None =&gt; EinaList { _eo: ptr::null_mut() },
            Some(l) =&gt; EinaList { _eo: l }
        };
        return v
    }
}"><pre class="notranslate"><span class="pl-k">impl</span><span class="pl-kos">&lt;</span><span class="pl-c1">'</span><span class="pl-ent">r</span><span class="pl-kos">,</span> <span class="pl-smi">T</span><span class="pl-kos">&gt;</span> <span class="pl-smi">Iterator</span> <span class="pl-k">for</span> <span class="pl-smi">EinaList</span><span class="pl-kos">&lt;</span><span class="pl-c1">'</span><span class="pl-ent">r</span><span class="pl-kos">,</span> <span class="pl-smi">T</span><span class="pl-kos">&gt;</span> <span class="pl-kos">{</span>
    <span class="pl-k">fn</span> <span class="pl-en">next</span><span class="pl-kos">(</span><span class="pl-c1">&amp;</span><span class="pl-k">mut</span> <span class="pl-smi">self</span><span class="pl-kos">)</span> -&gt; <span class="pl-smi">Option</span><span class="pl-kos">&lt;</span><span class="pl-c1">&amp;</span><span class="pl-c1">'</span><span class="pl-ent">r</span> <span class="pl-smi">T</span><span class="pl-kos">&gt;</span> <span class="pl-kos">{</span>
        <span class="pl-k">let</span> v = <span class="pl-en">list_data_get</span><span class="pl-kos">(</span><span class="pl-smi">self</span><span class="pl-kos">.</span><span class="pl-c1">_eo</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
        <span class="pl-c1">*</span><span class="pl-smi">self</span> = <span class="pl-k">match</span> <span class="pl-en">list_next</span><span class="pl-kos">(</span><span class="pl-smi">self</span><span class="pl-kos">.</span><span class="pl-c1">_eo</span><span class="pl-kos">)</span> <span class="pl-kos">{</span>
            <span class="pl-v">None</span> =&gt; <span class="pl-smi">EinaList</span> <span class="pl-kos">{</span> <span class="pl-c1">_eo</span><span class="pl-kos">:</span> ptr<span class="pl-kos">::</span><span class="pl-en">null_mut</span><span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-kos">}</span><span class="pl-kos">,</span>
            <span class="pl-v">Some</span><span class="pl-kos">(</span>l<span class="pl-kos">)</span> =&gt; <span class="pl-smi">EinaList</span> <span class="pl-kos">{</span> <span class="pl-c1">_eo</span><span class="pl-kos">:</span> l <span class="pl-kos">}</span>
        <span class="pl-kos">}</span><span class="pl-kos">;</span>
        <span class="pl-k">return</span> v
    <span class="pl-kos">}</span>
<span class="pl-kos">}</span></pre></div>
<p dir="auto">The compiler throws the following error (backtrace included):</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="src/eio.rs:27:3: 27:18 warning: `deriving` is deprecated; use `derive`
src/eio.rs:27 #[deriving(Show)]
                ^~~~~~~~~~~~~~~
src/eet.rs:69:3: 69:33 warning: `deriving` is deprecated; use `derive`
src/eet.rs:69 #[deriving(Show, FromPrimitive)]
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/eina.rs:196:1: 207:2 error: internal compiler error: impl `VtableImpl(impl_def_id=DefId { krate: 0, node: 2766 }:eina::EinaList&lt;'r, T&gt;.Iterator, substs=Substs[types=[[_];[];[]], regions=[['_#0r];[];[]]], nested=[[Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::kinds::Sized))),depth=1)];[];[]])` did not contain projection for `Obligation(predicate=&lt;eina::EinaList&lt;'r, T&gt; as TraitRef(eina::EinaList&lt;'r, T&gt;, core::iter::Iterator)&gt;::Item,depth=0)`
src/eina.rs:196 impl&lt;'r, T&gt; Iterator for EinaList&lt;'r, T&gt; {
src/eina.rs:197 
src/eina.rs:198     fn next(&amp;mut self) -&gt; Option&lt;&amp;'r T&gt; {
src/eina.rs:199         let v = list_data_get(self._eo);
src/eina.rs:200         *self = match list_next(self._eo) {
src/eina.rs:201             None =&gt; EinaList { _eo: ptr::null_mut() },
                ...
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;', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:123

stack backtrace:
   1: 0x40233e30 - sys::backtrace::write::hd07b456e2fb2edc64it
   2: 0x40258680 - failure::on_fail::hc26c935da551c95azvz
   3: 0x401c0c10 - rt::unwind::begin_unwind_inner::he25945c8d3f9a8c2eaz
   4: 0x43c32c60 - rt::unwind::begin_unwind::h5827585231859819369
   5: 0x43c32bd0 - diagnostic::SpanHandler::span_bug::h9f9dede6a55a96f0DFF
   6: 0x4133ad30 - middle::traits::project::project_type::h2397f2bdf09c070052P
   7: 0x41337e20 - middle::traits::project::opt_normalize_projection_type::h9840021934a72d668UP
   8: 0x41326640 - middle::traits::project::normalize_projection_type::h784de1d4a68f87bfJTP
   9: 0x413391c0 - middle::traits::project::AssociatedTypeNormalizer&lt;'a, 'b, 'tcx&gt;.TypeFolder&lt;'tcx&gt;::fold_ty::h93dc24df4c299e53kSP
  10: 0x4078b870 - middle::ty_fold::Rc&lt;T&gt;.TypeFoldable&lt;'tcx&gt;::fold_with::h14798399643135356730
  11: 0x4078c460 - middle::ty_fold::VecPerParamSpace&lt;T&gt;.TypeFoldable&lt;'tcx&gt;::fold_with::h9678217035264924423
  12: 0x407a85c0 - check::FnCtxt&lt;'a, 'tcx&gt;::instantiate_bounds::h965cba437f15b636Oll
  13: 0x407c1050 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;::check_impl::closure.29994
  14: 0x407bd180 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;::with_fcx::h551410613b5bc2f0Gfi
  15: 0x407c3d40 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;.Visitor&lt;'v&gt;::visit_item::h42e9f9bd2e45c68esoi
  16: 0x407c58c0 - visit::walk_mod::h8273770565610179432
  17: 0x407c3d40 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;.Visitor&lt;'v&gt;::visit_item::h42e9f9bd2e45c68esoi
  18: 0x409cad20 - check_crate::unboxed_closure.40159
  19: 0x409c5560 - check_crate::h1a6ec5dffa2bd3a7jsx
  20: 0x40060dc0 - driver::phase_3_run_analysis_passes::hdf5c0700c25562beTva
  21: 0x4004ee90 - driver::compile_input::hc6337ba6b18bc0dewba
  22: 0x40121170 - thunk::F.Invoke&lt;A, R&gt;::invoke::h8973449830402138319
  23: 0x4011ff80 - rt::unwind::try::try_fn::h4951350354602804749
  24: 0x402c8ba0 - rust_try_inner
  25: 0x402c8b70 - rust_try
  26: 0x401202c0 - thunk::F.Invoke&lt;A, R&gt;::invoke::h9098173034894979218
  27: 0x402455d0 - sys::thread::thread_start::h92aa6f5030fe4b1ca9v
  28: 0x443d1ea0 - start_thread
  29: 0x4063c472 - clone
  30:        0x0 - &lt;unknown&gt;

make: *** [libefl.rlib] Error 101"><pre class="notranslate"><code class="notranslate">src/eio.rs:27:3: 27:18 warning: `deriving` is deprecated; use `derive`
src/eio.rs:27 #[deriving(Show)]
                ^~~~~~~~~~~~~~~
src/eet.rs:69:3: 69:33 warning: `deriving` is deprecated; use `derive`
src/eet.rs:69 #[deriving(Show, FromPrimitive)]
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/eina.rs:196:1: 207:2 error: internal compiler error: impl `VtableImpl(impl_def_id=DefId { krate: 0, node: 2766 }:eina::EinaList&lt;'r, T&gt;.Iterator, substs=Substs[types=[[_];[];[]], regions=[['_#0r];[];[]]], nested=[[Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::kinds::Sized))),depth=1)];[];[]])` did not contain projection for `Obligation(predicate=&lt;eina::EinaList&lt;'r, T&gt; as TraitRef(eina::EinaList&lt;'r, T&gt;, core::iter::Iterator)&gt;::Item,depth=0)`
src/eina.rs:196 impl&lt;'r, T&gt; Iterator for EinaList&lt;'r, T&gt; {
src/eina.rs:197 
src/eina.rs:198     fn next(&amp;mut self) -&gt; Option&lt;&amp;'r T&gt; {
src/eina.rs:199         let v = list_data_get(self._eo);
src/eina.rs:200         *self = match list_next(self._eo) {
src/eina.rs:201             None =&gt; EinaList { _eo: ptr::null_mut() },
                ...
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;', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:123

stack backtrace:
   1: 0x40233e30 - sys::backtrace::write::hd07b456e2fb2edc64it
   2: 0x40258680 - failure::on_fail::hc26c935da551c95azvz
   3: 0x401c0c10 - rt::unwind::begin_unwind_inner::he25945c8d3f9a8c2eaz
   4: 0x43c32c60 - rt::unwind::begin_unwind::h5827585231859819369
   5: 0x43c32bd0 - diagnostic::SpanHandler::span_bug::h9f9dede6a55a96f0DFF
   6: 0x4133ad30 - middle::traits::project::project_type::h2397f2bdf09c070052P
   7: 0x41337e20 - middle::traits::project::opt_normalize_projection_type::h9840021934a72d668UP
   8: 0x41326640 - middle::traits::project::normalize_projection_type::h784de1d4a68f87bfJTP
   9: 0x413391c0 - middle::traits::project::AssociatedTypeNormalizer&lt;'a, 'b, 'tcx&gt;.TypeFolder&lt;'tcx&gt;::fold_ty::h93dc24df4c299e53kSP
  10: 0x4078b870 - middle::ty_fold::Rc&lt;T&gt;.TypeFoldable&lt;'tcx&gt;::fold_with::h14798399643135356730
  11: 0x4078c460 - middle::ty_fold::VecPerParamSpace&lt;T&gt;.TypeFoldable&lt;'tcx&gt;::fold_with::h9678217035264924423
  12: 0x407a85c0 - check::FnCtxt&lt;'a, 'tcx&gt;::instantiate_bounds::h965cba437f15b636Oll
  13: 0x407c1050 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;::check_impl::closure.29994
  14: 0x407bd180 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;::with_fcx::h551410613b5bc2f0Gfi
  15: 0x407c3d40 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;.Visitor&lt;'v&gt;::visit_item::h42e9f9bd2e45c68esoi
  16: 0x407c58c0 - visit::walk_mod::h8273770565610179432
  17: 0x407c3d40 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;.Visitor&lt;'v&gt;::visit_item::h42e9f9bd2e45c68esoi
  18: 0x409cad20 - check_crate::unboxed_closure.40159
  19: 0x409c5560 - check_crate::h1a6ec5dffa2bd3a7jsx
  20: 0x40060dc0 - driver::phase_3_run_analysis_passes::hdf5c0700c25562beTva
  21: 0x4004ee90 - driver::compile_input::hc6337ba6b18bc0dewba
  22: 0x40121170 - thunk::F.Invoke&lt;A, R&gt;::invoke::h8973449830402138319
  23: 0x4011ff80 - rt::unwind::try::try_fn::h4951350354602804749
  24: 0x402c8ba0 - rust_try_inner
  25: 0x402c8b70 - rust_try
  26: 0x401202c0 - thunk::F.Invoke&lt;A, R&gt;::invoke::h9098173034894979218
  27: 0x402455d0 - sys::thread::thread_start::h92aa6f5030fe4b1ca9v
  28: 0x443d1ea0 - start_thread
  29: 0x4063c472 - clone
  30:        0x0 - &lt;unknown&gt;

make: *** [libefl.rlib] Error 101
</code></pre></div>
<p dir="auto">rustc version:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="rustc 0.13.0-nightly (c6c786671 2015-01-04 00:50:59 +0000)
binary: rustc
commit-hash: c6c786671d692d7b13c2e5c68a53001327b4b125
commit-date: 2015-01-04 00:50:59 +0000
host: i686-unknown-linux-gnu
release: 0.13.0-nightly"><pre class="notranslate"><code class="notranslate">rustc 0.13.0-nightly (c6c786671 2015-01-04 00:50:59 +0000)
binary: rustc
commit-hash: c6c786671d692d7b13c2e5c68a53001327b4b125
commit-date: 2015-01-04 00:50:59 +0000
host: i686-unknown-linux-gnu
release: 0.13.0-nightly
</code></pre></div>
<p dir="auto">When trying to use this feature in <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="53342892" data-permission-text="Title is private" data-url="https://github.com/japaric-archived/complex.rs/issues/9" data-hovercard-type="pull_request" data-hovercard-url="/japaric-archived/complex.rs/pull/9/hovercard" href="https://github.com/japaric-archived/complex.rs/pull/9">japaric-archived/complex.rs#9</a>, the following happened:</p>
<div class="highlight highlight-text-python-traceback notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="   Compiling complex v0.0.0 (file:///home/phil/Dev/rust/_foreign_projects/complex.rs)
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:149:1: 156:2 error: internal compiler error: impl `VtableImpl(impl_def_id=DefId { krate: 0, node: 1681 }:Complex&lt;T&gt;.Neg, substs=Substs[types=[[_];[];[]], regions=[[];[];[]]], nested=[[Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::kinds::Sized))),depth=1), Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::ops::Neg))),depth=1)];[];[]])` did not contain projection for `Obligation(predicate=&lt;Complex&lt;T&gt; as TraitRef(Complex&lt;T&gt;, core::ops::Neg)&gt;::Output,depth=0)`
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:149 impl&lt;T&gt; Neg for Complex&lt;T&gt; where T: Neg {
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:150     fn neg(self) -&gt; Complex&lt;T&gt; {
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:151         Complex {
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:152             re: -self.re,
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:153             im: -self.im,
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:154         }
                                                                ...
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;', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:123

stack backtrace:
   1:     0x7f6d403552d0 - sys::backtrace::write::h8532e701ef86014f4it
   2:     0x7f6d4037ab00 - failure::on_fail::h7532e1f79d134d5dzvz
   3:     0x7f6d402e01c0 - rt::unwind::begin_unwind_inner::h97b151606151d62deaz
   4:     0x7f6d3b1b4c60 - rt::unwind::begin_unwind::h15809447133099964284
   5:     0x7f6d3b1b4bf0 - diagnostic::SpanHandler::span_bug::he8142ababcc30c39DFF
   6:     0x7f6d3e6b3e70 - middle::traits::project::project_type::h947eece142ef049d52P
   7:     0x7f6d3e6b0fd0 - middle::traits::project::opt_normalize_projection_type::hb3defb9cc9365d1e8UP
   8:     0x7f6d3e69eba0 - middle::traits::project::normalize_projection_type::hdc293893275ee559JTP
   9:     0x7f6d3e6b2470 - middle::traits::project::AssociatedTypeNormalizer&lt;'a, 'b, 'tcx&gt;.TypeFolder&lt;'tcx&gt;::fold_ty::h801cbd2cdff2eff1kSP
  10:     0x7f6d3f96f2e0 - middle::ty_fold::Rc&lt;T&gt;.TypeFoldable&lt;'tcx&gt;::fold_with::h6325524173844043840
  11:     0x7f6d3f96fe90 - middle::ty_fold::VecPerParamSpace&lt;T&gt;.TypeFoldable&lt;'tcx&gt;::fold_with::h13884369302522804796
  12:     0x7f6d3f98b280 - check::FnCtxt&lt;'a, 'tcx&gt;::instantiate_bounds::hed550a9659b70335Oll
  13:     0x7f6d3f9a3fc0 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;::check_impl::closure.29997
  14:     0x7f6d3f9a0430 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;::with_fcx::hb1283961ed8977b7Gfi
  15:     0x7f6d3f9a6d70 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;.Visitor&lt;'v&gt;::visit_item::h001ababd87597e37soi
  16:     0x7f6d3fb93fe0 - check_crate::unboxed_closure.40162
  17:     0x7f6d3fb8ec30 - check_crate::h19fb6dea5733566ajsx
  18:     0x7f6d408a6640 - driver::phase_3_run_analysis_passes::h46b1604d9f9f5633Tva
  19:     0x7f6d40894ae0 - driver::compile_input::h68b8602933aad8d7wba
  20:     0x7f6d4095feb0 - thunk::F.Invoke&lt;A, R&gt;::invoke::h18029802347644288836
  21:     0x7f6d4095ec60 - rt::unwind::try::try_fn::h6518866316425934196
  22:     0x7f6d403e1400 - rust_try_inner
  23:     0x7f6d403e13f0 - rust_try
  24:     0x7f6d4095efb0 - thunk::F.Invoke&lt;A, R&gt;::invoke::h15513809553472565307
  25:     0x7f6d40366e40 - sys::thread::thread_start::h5ea7ba97235331d5a9v
  26:     0x7f6d3a9d9250 - start_thread
  27:     0x7f6d3ff97219 - clone
  28:                0x0 - &lt;unknown&gt;

Could not compile `complex`.

To learn more, run the command again with --verbose."><pre class="notranslate">   Compiling complex v0.0.0 (file:///home/phil/Dev/rust/_foreign_projects/complex.rs)
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:149:1: 156:2 error: internal compiler error: impl `VtableImpl(impl_def_id=DefId { krate: 0, node: 1681 }:Complex&lt;T&gt;.Neg, substs=Substs[types=[[_];[];[]], regions=[[];[];[]]], nested=[[Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::kinds::Sized))),depth=1), Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::ops::Neg))),depth=1)];[];[]])` did not contain projection for `Obligation(predicate=&lt;Complex&lt;T&gt; as TraitRef(Complex&lt;T&gt;, core::ops::Neg)&gt;::Output,depth=0)`
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:149 impl&lt;T&gt; Neg for Complex&lt;T&gt; where T: Neg {
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:150     fn neg(self) -&gt; Complex&lt;T&gt; {
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:151         Complex {
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:152             re: -self.re,
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:153             im: -self.im,
/home/phil/Dev/rust/_foreign_projects/complex.rs/src/lib.rs:154         }
                                                                <span class="pl-c1">...</span>
<span class="pl-en">note</span>: <span class="pl-s">the compiler unexpectedly panicked. this is a bug.</span>
<span class="pl-en">note</span>: <span class="pl-s">we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html</span>
<span class="pl-en">note</span>: <span class="pl-s">run with `RUST_BACKTRACE=1` for a backtrace</span>
thread 'rustc' panicked at 'Box&lt;Any&gt;', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:123

stack backtrace:
   1:     0x7f6d403552d0 - sys::backtrace::write::h8532e701ef86014f4it
   2:     0x7f6d4037ab00 - failure::on_fail::h7532e1f79d134d5dzvz
   3:     0x7f6d402e01c0 - rt::unwind::begin_unwind_inner::h97b151606151d62deaz
   4:     0x7f6d3b1b4c60 - rt::unwind::begin_unwind::h15809447133099964284
   5:     0x7f6d3b1b4bf0 - diagnostic::SpanHandler::span_bug::he8142ababcc30c39DFF
   6:     0x7f6d3e6b3e70 - middle::traits::project::project_type::h947eece142ef049d52P
   7:     0x7f6d3e6b0fd0 - middle::traits::project::opt_normalize_projection_type::hb3defb9cc9365d1e8UP
   8:     0x7f6d3e69eba0 - middle::traits::project::normalize_projection_type::hdc293893275ee559JTP
   9:     0x7f6d3e6b2470 - middle::traits::project::AssociatedTypeNormalizer&lt;'a, 'b, 'tcx&gt;.TypeFolder&lt;'tcx&gt;::fold_ty::h801cbd2cdff2eff1kSP
  10:     0x7f6d3f96f2e0 - middle::ty_fold::Rc&lt;T&gt;.TypeFoldable&lt;'tcx&gt;::fold_with::h6325524173844043840
  11:     0x7f6d3f96fe90 - middle::ty_fold::VecPerParamSpace&lt;T&gt;.TypeFoldable&lt;'tcx&gt;::fold_with::h13884369302522804796
  12:     0x7f6d3f98b280 - check::FnCtxt&lt;'a, 'tcx&gt;::instantiate_bounds::hed550a9659b70335Oll
  13:     0x7f6d3f9a3fc0 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;::check_impl::closure.29997
  14:     0x7f6d3f9a0430 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;::with_fcx::hb1283961ed8977b7Gfi
  15:     0x7f6d3f9a6d70 - check::wf::CheckTypeWellFormedVisitor&lt;'ccx, 'tcx&gt;.Visitor&lt;'v&gt;::visit_item::h001ababd87597e37soi
  16:     0x7f6d3fb93fe0 - check_crate::unboxed_closure.40162
  17:     0x7f6d3fb8ec30 - check_crate::h19fb6dea5733566ajsx
  18:     0x7f6d408a6640 - driver::phase_3_run_analysis_passes::h46b1604d9f9f5633Tva
  19:     0x7f6d40894ae0 - driver::compile_input::h68b8602933aad8d7wba
  20:     0x7f6d4095feb0 - thunk::F.Invoke&lt;A, R&gt;::invoke::h18029802347644288836
  21:     0x7f6d4095ec60 - rt::unwind::try::try_fn::h6518866316425934196
  22:     0x7f6d403e1400 - rust_try_inner
  23:     0x7f6d403e13f0 - rust_try
  24:     0x7f6d4095efb0 - thunk::F.Invoke&lt;A, R&gt;::invoke::h15513809553472565307
  25:     0x7f6d40366e40 - sys::thread::thread_start::h5ea7ba97235331d5a9v
  26:     0x7f6d3a9d9250 - start_thread
  27:     0x7f6d3ff97219 - clone
  28:                0x0 - &lt;unknown&gt;

Could not compile `complex`.

To learn more, run the command again with --verbose.</pre></div>