<p dir="auto">Recently, Julia 0.5 started segfaulting when precompiling PyCall (<a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="207005427" data-permission-text="Title is private" data-url="https://github.com/JuliaPy/PyCall.jl/issues/360" data-hovercard-type="issue" data-hovercard-url="/JuliaPy/PyCall.jl/issues/360/hovercard" href="https://github.com/JuliaPy/PyCall.jl/issues/360">JuliaPy/PyCall.jl#360</a>).   I've boiled it down to the following code:</p>
<div class="highlight highlight-source-julia notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="__precompile__()

module PyCall

import MacroTools: @capture

function parse_pydef_toplevel(expr)
    if @capture(expr, begin type class_name_ &lt;: base_classes_expr_
                    lines__
                end end)
    end
end

end # module PyCall"><pre class="notranslate"><span class="pl-c1">__precompile__</span>()

<span class="pl-k">module</span> PyCall

<span class="pl-k">import</span> MacroTools<span class="pl-k">:</span> <span class="pl-c1">@capture</span>

<span class="pl-k">function</span> <span class="pl-en">parse_pydef_toplevel</span>(expr)
    <span class="pl-k">if</span> <span class="pl-c1">@capture</span>(expr, <span class="pl-k">begin</span> type class_name_ <span class="pl-k">&lt;:</span> <span class="pl-c1">base_classes_expr_</span>
                    lines__
                <span class="pl-k">end</span> <span class="pl-k">end</span>)
    <span class="pl-k">end</span>
<span class="pl-k">end</span>

<span class="pl-k">end</span> <span class="pl-c"><span class="pl-c">#</span> module PyCall</span></pre></div>
<p dir="auto">This gives:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="julia&gt; versioninfo()
Julia Version 0.5.0
Commit 3c9d753 (2016-09-19 18:14 UTC)
Platform Info:
  System: Darwin (x86_64-apple-darwin13.4.0)
  CPU: Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
  WORD_SIZE: 64
  BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Haswell)
  LAPACK: libopenblas64_
  LIBM: libopenlibm
  LLVM: libLLVM-3.7.1 (ORCJIT, haswell)

julia&gt; using PyCall
INFO: Precompiling module PyCall.

signal (11): Segmentation fault: 11
while loading /Users/stevenj/.julia/v0.5/PyCall/src/PyCall.jl, in expression starting on line 7
julia_type_to_llvm at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./cgutils.cpp:318
mark_julia_const at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:641 [inlined]
emit_expr at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:3140
emit_invoke at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:2669 [inlined]
emit_expr at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:3162
emit_jlcall at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:2578
emit_call at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:2739
emit_expr at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:3172
emit_function at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:4691
jl_compile_linfo at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:809
jl_compile_for_dispatch at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1310
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:184 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
@capture at /Users/stevenj/.julia/v0.5/MacroTools/src/macro.jl:61
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
fl_invoke_julia_macro at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/ast.c:161
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1227
_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:678
fl_map1 at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:2220
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1177
_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:678
fl_map1 at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:2220
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1177
_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:678
fl_map1 at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:2220
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1177
do_trycatch at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:899
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1807
_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:678
fl_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:723
jl_call_scm_on_ast at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/ast.c:778
jl_eval_module_expr at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:195
jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:465
jl_parse_eval_all at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/ast.c:717
jl_load at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:596 [inlined]
jl_load_ at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:605
include_from_node1 at ./loading.jl:488
jlcall_include_from_node1_20125 at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
do_call at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/interpreter.c:66
eval at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/interpreter.c:190
jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:558
jl_toplevel_eval_in_warn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/builtins.c:590
macro expansion; at ./none:2 [inlined]
anonymous at ./&lt;missing&gt; (unknown line)
unknown function (ip: 0x116df16c1)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:569
jl_toplevel_eval_in_warn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/builtins.c:590
eval at ./boot.jl:234
jlcall_eval_19752 at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
process_options at ./client.jl:239
_start at ./client.jl:318
jlcall__start_21452 at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
true_main at /Applications/Julia-0.5.app/Contents/Resources/julia/bin/julia (unknown line)
main at /Applications/Julia-0.5.app/Contents/Resources/julia/bin/julia (unknown line)
Allocations: 1202188 (Pool: 1201349; Big: 839); GC: 0
ERROR: Failed to precompile PyCall to /Users/stevenj/.julia/lib/v0.5/PyCall.ji.
 in compilecache(::String) at ./loading.jl:593
 in require(::Symbol) at ./loading.jl:422
 in require(::Symbol) at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib:?"><pre class="notranslate"><code class="notranslate">julia&gt; versioninfo()
Julia Version 0.5.0
Commit 3c9d753 (2016-09-19 18:14 UTC)
Platform Info:
  System: Darwin (x86_64-apple-darwin13.4.0)
  CPU: Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
  WORD_SIZE: 64
  BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Haswell)
  LAPACK: libopenblas64_
  LIBM: libopenlibm
  LLVM: libLLVM-3.7.1 (ORCJIT, haswell)

julia&gt; using PyCall
INFO: Precompiling module PyCall.

signal (11): Segmentation fault: 11
while loading /Users/stevenj/.julia/v0.5/PyCall/src/PyCall.jl, in expression starting on line 7
julia_type_to_llvm at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./cgutils.cpp:318
mark_julia_const at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:641 [inlined]
emit_expr at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:3140
emit_invoke at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:2669 [inlined]
emit_expr at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:3162
emit_jlcall at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:2578
emit_call at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:2739
emit_expr at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:3172
emit_function at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:4691
jl_compile_linfo at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/codegen.cpp:809
jl_compile_for_dispatch at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1310
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:184 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
@capture at /Users/stevenj/.julia/v0.5/MacroTools/src/macro.jl:61
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
fl_invoke_julia_macro at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/ast.c:161
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1227
_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:678
fl_map1 at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:2220
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1177
_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:678
fl_map1 at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:2220
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1177
_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:678
fl_map1 at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:2220
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1177
do_trycatch at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:899
apply_cl at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:1807
_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:678
fl_applyn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/flisp/flisp.c:723
jl_call_scm_on_ast at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/ast.c:778
jl_eval_module_expr at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:195
jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:465
jl_parse_eval_all at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/ast.c:717
jl_load at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:596 [inlined]
jl_load_ at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:605
include_from_node1 at ./loading.jl:488
jlcall_include_from_node1_20125 at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
do_call at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/interpreter.c:66
eval at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/interpreter.c:190
jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:558
jl_toplevel_eval_in_warn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/builtins.c:590
macro expansion; at ./none:2 [inlined]
anonymous at ./&lt;missing&gt; (unknown line)
unknown function (ip: 0x116df16c1)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:569
jl_toplevel_eval_in_warn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/builtins.c:590
eval at ./boot.jl:234
jlcall_eval_19752 at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
process_options at ./client.jl:239
_start at ./client.jl:318
jlcall__start_21452 at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
true_main at /Applications/Julia-0.5.app/Contents/Resources/julia/bin/julia (unknown line)
main at /Applications/Julia-0.5.app/Contents/Resources/julia/bin/julia (unknown line)
Allocations: 1202188 (Pool: 1201349; Big: 839); GC: 0
ERROR: Failed to precompile PyCall to /Users/stevenj/.julia/lib/v0.5/PyCall.ji.
 in compilecache(::String) at ./loading.jl:593
 in require(::Symbol) at ./loading.jl:422
 in require(::Symbol) at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib:?
</code></pre></div>
<p dir="auto">This is with MacroTools 0.3.5.</p>
<p dir="auto">In one of my private repos tests pass locally on <code class="notranslate">release-0.5</code> but fail on Travis, and the failure looks consistent with a difference between what was tagged as <code class="notranslate">0.5.0</code> and what's in <code class="notranslate">release-0.5</code>. Are there plans for point-releases of 0.5, or are we going straight to 0.6? If nothing else, any chance we can "bless" what's in <code class="notranslate">release-0.5</code> now as <code class="notranslate">0.5.1</code> and call that good enough?</p>