Internal error in runtime when testing Meshing.jl

[rdeits]

This error occurs reliably for me when running Pkg.test for Meshing.jl on this branch with GeometryTypes.jl at fd82434. The tests still pass, and everything seems to work correctly, but I get a very long internal backtrace from Julia.

Here's a partial copy of that backtrace:

Internal error: encountered unexpected error in runtime:
TypeError(func=:<:, context="", expected=Type{T} where T, got=_)
rec_backtrace at /buildworker/worker/package_linux64/build/src/stackwalk.c:94
record_backtrace at /buildworker/worker/package_linux64/build/src/task.c:246
jl_throw at /buildworker/worker/package_linux64/build/src/task.c:577
jl_type_error_rt at /buildworker/worker/package_linux64/build/src/rtutils.c:118
jl_type_error at /buildworker/worker/package_linux64/build/src/rtutils.c:124
jl_f_issubtype at /buildworker/worker/package_linux64/build/src/builtins.c:414
tuplemerge at ./compiler/typelimits.jl:434
tmerge at ./compiler/typelimits.jl:375
getfield_tfunc at ./compiler/tfuncs.jl:667
jl_apply_generic at /buildworker/worker/package_linux64/build/src/gf.c:2182
jl_apply at /buildworker/worker/package_linux64/build/src/julia.h:1538 [inlined]
jl_f__apply at /buildworker/worker/package_linux64/build/src/builtins.c:563
builtin_tfunction at ./compiler/tfuncs.jl:1170
builtin_tfunction at ./compiler/tfuncs.jl:1079
abstract_call at ./compiler/abstractinterpretation.jl:551
abstract_eval_call at ./compiler/abstractinterpretation.jl:798
abstract_eval at ./compiler/abstractinterpretation.jl:883
typeinf_local at ./compiler/abstractinterpretation.jl:1107
typeinf_nocycle at ./compiler/abstractinterpretation.jl:1163
typeinf at ./compiler/typeinfer.jl:15
typeinf_edge at ./compiler/typeinfer.jl:492
abstract_call_method at ./compiler/abstractinterpretation.jl:321
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:81
abstract_call at ./compiler/abstractinterpretation.jl:769
abstract_eval_call at ./compiler/abstractinterpretation.jl:798
abstract_eval at ./compiler/abstractinterpretation.jl:883
typeinf_local at ./compiler/abstractinterpretation.jl:1107
typeinf_nocycle at ./compiler/abstractinterpretation.jl:1163
typeinf at ./compiler/typeinfer.jl:15
typeinf_edge at ./compiler/typeinfer.jl:492
abstract_call_method at ./compiler/abstractinterpretation.jl:321
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:81
abstract_call at ./compiler/abstractinterpretation.jl:769
abstract_eval_call at ./compiler/abstractinterpretation.jl:798
abstract_eval at ./compiler/abstractinterpretation.jl:883
typeinf_local at ./compiler/abstractinterpretation.jl:1107
typeinf_nocycle at ./compiler/abstractinterpretation.jl:1163
typeinf at ./compiler/typeinfer.jl:15
typeinf_ext at ./compiler/typeinfer.jl:567
typeinf_ext at ./compiler/typeinfer.jl:604
jfptr_typeinf_ext_1.clone_1 at /home/rdeits/apps/julia-0.7.0/lib/julia/sys.so (unknown line)
jl_apply_generic at /buildworker/worker/package_linux64/build/src/gf.c:2182
jl_apply at /buildworker/worker/package_linux64/build/src/julia.h:1538 [inlined]
jl_apply_with_saved_exception_state at /buildworker/worker/package_linux64/build/src/rtutils.c:257
jl_type_infer at /buildworker/worker/package_linux64/build/src/gf.c:275
jl_compile_method_internal at /buildworker/worker/package_linux64/build/src/gf.c:1784 [inlined]
jl_fptr_trampoline at /buildworker/worker/package_linux64/build/src/gf.c:1828
jl_apply_generic at /buildworker/worker/package_linux64/build/src/gf.c:2182
isosurface at /home/rdeits/.julia/dev/Meshing/src/marching_tetrahedra.jl:278 [inlined]
Type at /home/rdeits/.julia/dev/Meshing/src/marching_tetrahedra.jl:324
unknown function (ip: 0x7f688d84a2fc)

and the full backtrace is here: https://gist.github.com/rdeits/e0043a0b0d39a794ecde83651267f2cc

This occurs for me on both Julia 0.7.0 and Julia 1.0.0.

julia> versioninfo()
Julia Version 1.0.0
Commit 5d4eaca0c9 (2018-08-08 20:58 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.0 (ORCJIT, skylake)