statestack_set assertion in subtype resolution

[olynch]

I'm getting a segfault in the subtype resolution. I'm not sure how to track this down to its source, but you can reproduce if you clone this commit of Catlab.jl, and then run julia --project=test test/wiring_diagrams/WiringDiagrams.jl. What I get when I run this is:

signal (11): Segmentation fault
in expression starting at /home/o/g/topos/Catlab.jl/test/wiring_diagrams/Directed.jl:177
subtype_unionall at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:793
subtype at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:1257
subtype_unionall at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:805
subtype at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:1254
subtype_unionall at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:805
subtype at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:1254
subtype_unionall at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:805
subtype at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:1254
exists_subtype at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:1391 [inlined]
forall_exists_subtype at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:1419
ijl_subtype_env at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/subtype.c:1881
jl_f_issubtype at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/builtins.c:509
⊑ at ./compiler/typelattice.jl:234
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:157
abstract_call_known at ./compiler/abstractinterpretation.jl:1716
abstract_call at ./compiler/abstractinterpretation.jl:1786
abstract_call at ./compiler/abstractinterpretation.jl:1753
abstract_eval_statement at ./compiler/abstractinterpretation.jl:1910
typeinf_local at ./compiler/abstractinterpretation.jl:2386
typeinf_nocycle at ./compiler/abstractinterpretation.jl:2482
_typeinf at ./compiler/typeinfer.jl:230
typeinf at ./compiler/typeinfer.jl:213
typeinf_edge at ./compiler/typeinfer.jl:877
abstract_call_method at ./compiler/abstractinterpretation.jl:647
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:139
abstract_call_known at ./compiler/abstractinterpretation.jl:1716
abstract_call at ./compiler/abstractinterpretation.jl:1786
abstract_call at ./compiler/abstractinterpretation.jl:1753
abstract_eval_statement at ./compiler/abstractinterpretation.jl:1910
typeinf_local at ./compiler/abstractinterpretation.jl:2360
typeinf_nocycle at ./compiler/abstractinterpretation.jl:2482
_typeinf at ./compiler/typeinfer.jl:230
typeinf at ./compiler/typeinfer.jl:213
typeinf_edge at ./compiler/typeinfer.jl:877
abstract_call_method at ./compiler/abstractinterpretation.jl:647
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:139
abstract_call_known at ./compiler/abstractinterpretation.jl:1716
abstract_call at ./compiler/abstractinterpretation.jl:1786
abstract_call at ./compiler/abstractinterpretation.jl:1753
abstract_eval_statement at ./compiler/abstractinterpretation.jl:1910
typeinf_local at ./compiler/abstractinterpretation.jl:2386
typeinf_nocycle at ./compiler/abstractinterpretation.jl:2482
_typeinf at ./compiler/typeinfer.jl:230
typeinf at ./compiler/typeinfer.jl:213
typeinf_edge at ./compiler/typeinfer.jl:877
abstract_call_method at ./compiler/abstractinterpretation.jl:647
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:139
abstract_call_known at ./compiler/abstractinterpretation.jl:1716
abstract_call at ./compiler/abstractinterpretation.jl:1786
abstract_call at ./compiler/abstractinterpretation.jl:1753
abstract_eval_statement at ./compiler/abstractinterpretation.jl:1910
typeinf_local at ./compiler/abstractinterpretation.jl:2386
typeinf_nocycle at ./compiler/abstractinterpretation.jl:2482
_typeinf at ./compiler/typeinfer.jl:230
typeinf at ./compiler/typeinfer.jl:213
typeinf_edge at ./compiler/typeinfer.jl:877
abstract_call_method at ./compiler/abstractinterpretation.jl:647
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:139
abstract_call_known at ./compiler/abstractinterpretation.jl:1716
abstract_call at ./compiler/abstractinterpretation.jl:1786
abstract_call at ./compiler/abstractinterpretation.jl:1753
abstract_eval_statement at ./compiler/abstractinterpretation.jl:1910
typeinf_local at ./compiler/abstractinterpretation.jl:2386
typeinf_nocycle at ./compiler/abstractinterpretation.jl:2482
_typeinf at ./compiler/typeinfer.jl:230
typeinf at ./compiler/typeinfer.jl:213
typeinf_edge at ./compiler/typeinfer.jl:877
abstract_call_method at ./compiler/abstractinterpretation.jl:647
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:139
abstract_call_known at ./compiler/abstractinterpretation.jl:1716
abstract_call at ./compiler/abstractinterpretation.jl:1786
abstract_call at ./compiler/abstractinterpretation.jl:1753
abstract_eval_statement at ./compiler/abstractinterpretation.jl:1910
typeinf_local at ./compiler/abstractinterpretation.jl:2386
typeinf_nocycle at ./compiler/abstractinterpretation.jl:2482
_typeinf at ./compiler/typeinfer.jl:230
typeinf at ./compiler/typeinfer.jl:213
typeinf_edge at ./compiler/typeinfer.jl:877
abstract_call_method at ./compiler/abstractinterpretation.jl:647
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:139
abstract_call_known at ./compiler/abstractinterpretation.jl:1716
abstract_call at ./compiler/abstractinterpretation.jl:1786
abstract_call at ./compiler/abstractinterpretation.jl:1753
abstract_eval_statement at ./compiler/abstractinterpretation.jl:1910
typeinf_local at ./compiler/abstractinterpretation.jl:2386
typeinf_nocycle at ./compiler/abstractinterpretation.jl:2482
_typeinf at ./compiler/typeinfer.jl:230
typeinf at ./compiler/typeinfer.jl:213
typeinf_edge at ./compiler/typeinfer.jl:877
abstract_call_method at ./compiler/abstractinterpretation.jl:647
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:139
abstract_call_known at ./compiler/abstractinterpretation.jl:1716
abstract_call at ./compiler/abstractinterpretation.jl:1786
abstract_call at ./compiler/abstractinterpretation.jl:1753
abstract_eval_statement at ./compiler/abstractinterpretation.jl:1910
typeinf_local at ./compiler/abstractinterpretation.jl:2386
typeinf_nocycle at ./compiler/abstractinterpretation.jl:2482
_typeinf at ./compiler/typeinfer.jl:230
typeinf at ./compiler/typeinfer.jl:213
typeinf_ext at ./compiler/typeinfer.jl:967
typeinf_ext_toplevel at ./compiler/typeinfer.jl:1000
typeinf_ext_toplevel at ./compiler/typeinfer.jl:996
jfptr_typeinf_ext_toplevel_17736.clone_1 at /nix/store/xrjyvk8mkfxka8c72h52md040wwbz5mn-julia-1.8.3/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2365 [inlined]
ijl_apply_generic at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2547
jl_apply at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/julia.h:1839 [inlined]
jl_type_infer at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:317
jl_generate_fptr_impl at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/jitlayers.cpp:319
jl_compile_method_internal at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2079 [inlined]
jl_compile_method_internal at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2023
_jl_invoke at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2357 [inlined]
ijl_apply_generic at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2547
jl_apply at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/julia.h:1839 [inlined]
do_call at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:126
eval_value at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:215
eval_stmt_value at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:166 [inlined]
eval_body at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:612
jl_interpret_toplevel_thunk at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:750
jl_toplevel_eval_flex at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/toplevel.c:906
jl_eval_module_expr at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/toplevel.c:203 [inlined]
jl_toplevel_eval_flex at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/toplevel.c:709
jl_toplevel_eval_flex at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/toplevel.c:850
ijl_toplevel_eval_in at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/toplevel.c:965
eval at ./boot.jl:368 [inlined]
include_string at ./loading.jl:1428
_jl_invoke at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2365 [inlined]
ijl_apply_generic at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2547
_include at ./loading.jl:1488
include at ./client.jl:476
unknown function (ip: 0x7f4e0c700dc2)
_jl_invoke at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2365 [inlined]
ijl_apply_generic at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2547
jl_apply at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/julia.h:1839 [inlined]
do_call at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:126
eval_value at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:215
eval_stmt_value at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:166 [inlined]
eval_body at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:612
eval_body at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:522
eval_body at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:522
jl_interpret_toplevel_thunk at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/interpreter.c:750
jl_toplevel_eval_flex at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/toplevel.c:906
jl_toplevel_eval_flex at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/toplevel.c:850
ijl_toplevel_eval_in at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/toplevel.c:965
eval at ./boot.jl:368 [inlined]
include_string at ./loading.jl:1428
_jl_invoke at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2365 [inlined]
ijl_apply_generic at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2547
_include at ./loading.jl:1488
include at ./Base.jl:419
jfptr_include_57158.clone_1 at /nix/store/xrjyvk8mkfxka8c72h52md040wwbz5mn-julia-1.8.3/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2365 [inlined]
ijl_apply_generic at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2547
exec_options at ./client.jl:303
_start at ./client.jl:522
jfptr__start_27977.clone_1 at /nix/store/xrjyvk8mkfxka8c72h52md040wwbz5mn-julia-1.8.3/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2365 [inlined]
ijl_apply_generic at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/gf.c:2547
jl_apply at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/julia.h:1839 [inlined]
true_main at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/jlapi.c:575
jl_repl_entrypoint at /cache/build/default-amdci5-6/julialang/julia-release-1-dot-8/src/jlapi.c:719
main at julia (unknown line)
__libc_start_call_main at /usr/lib/libc.so.6 (unknown line)
__libc_start_main at /usr/lib/libc.so.6 (unknown line)
unknown function (ip: 0x401098)
Allocations: 37948610 (Pool: 37937867; Big: 10743); GC: 45

My feeling is that perhaps if the underlying logical error of #47654 is sorted out, this might be fixed as a side-effect, but then again it could be completely unrelated.

[vtjnash]

I first hit this unrelated issue, but this is a StaticArrays bug. We could fix this is Julia, but my PR was reverted. I will update again if I hit the specific bug mentioned once it finishes building.

$ ./julia --project="/home/vtjnash/.julia/packages/Catlab/4kBOe/test" "/home/vtjnash/.julia/packages/Catlab/4kBOe/test/wiring_diagrams/WiringDiagrams.jl"
ERROR: LoadError: AssertionError: precompile(Tuple{typeof((which(__broadcast, (Any, Size, Tuple{Vararg{Size}}, Vararg{Any}))).generator.gen), Any, Any, Any, Any, Any, Any})
Stacktrace:                                                                                                                                                                                            
 [1] _precompile_()                                                                                                                                                                                    
   @ StaticArrays ~/.julia/packages/StaticArrays/x7lS0/src/precompile.jl:25                        
 [2] top-level scope                                                                                                                                                                                   
   @ ~/.julia/packages/StaticArrays/x7lS0/src/StaticArrays.jl:137                                                                                                                                      
 [3] include                                                                                                                                                                                           
   @ ./Base.jl:450 [inlined]                                                                       
 [4] include_package_for_output(pkg::Base.PkgId, input::String, depot_path::Vector{String}, dl_load_path::Vector{String}, load_path::Vector{String}, concrete_deps::Vector{Pair{Base.PkgId, UInt64}}, s
ource::String)                                  
   @ Base ./loading.jl:1667                                                                                                                                                                            
 [5] top-level scope                                                                               
   @ stdin:1                                                                                                                                                                                           
in expression starting at /home/vtjnash/.julia/packages/StaticArrays/x7lS0/src/StaticArrays.jl:1   
in expression starting at stdin:1                                                                  
ERROR: LoadError: Failed to precompile StaticArrays [90137ffa-7385-5640-81b9-e52037218182] to /home/vtjnash/.julia/compiled/v1.10/StaticArrays/jl_6Fx4bc.                                              

[vtjnash]

Running this test locally, I get:

$ ./julia --project="/home/vtjnash/.julia/packages/Catlab/4kBOe/" "/home/vtjnash/.julia/packages/Catlab/4kBOe/test/wiring_diagrams/WiringDiagrams.jl"
julia: /data/vtjnash/julia/src/subtype.c:137: statestack_set: Assertion `i >= 0 && i < sizeof(st->stack) * 8' failed.

[1631390] signal (6.-6): Aborted
in expression starting at /home/vtjnash/.julia/packages/Catlab/4kBOe/test/wiring_diagrams/Directed.jl:177
gsignal at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
abort at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
unknown function (ip: 0x7f47eef71728)
__assert_fail at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
statestack_set at /data/vtjnash/julia/src/subtype.c:137
statestack_set at /data/vtjnash/julia/src/subtype.c:130 [inlined]
subtype at /data/vtjnash/julia/src/subtype.c:1185
forall_exists_equal at /data/vtjnash/julia/src/subtype.c:1372
subtype at /data/vtjnash/julia/src/subtype.c:1307
forall_exists_equal at /data/vtjnash/julia/src/subtype.c:1384
subtype at /data/vtjnash/julia/src/subtype.c:1307
subtype_tuple_tail at /data/vtjnash/julia/src/subtype.c:1079 [inlined]
subtype_tuple at /data/vtjnash/julia/src/subtype.c:1158 [inlined]
subtype at /data/vtjnash/julia/src/subtype.c:1300
forall_exists_equal at /data/vtjnash/julia/src/subtype.c:1372
subtype at /data/vtjnash/julia/src/subtype.c:1307
subtype_unionall at /data/vtjnash/julia/src/subtype.c:775
subtype at /data/vtjnash/julia/src/subtype.c:1260
subtype_unionall at /data/vtjnash/julia/src/subtype.c:775
subtype at /data/vtjnash/julia/src/subtype.c:1260
subtype_unionall at /data/vtjnash/julia/src/subtype.c:775
subtype at /data/vtjnash/julia/src/subtype.c:1260
subtype_unionall at /data/vtjnash/julia/src/subtype.c:782
subtype at /data/vtjnash/julia/src/subtype.c:1257
subtype_unionall at /data/vtjnash/julia/src/subtype.c:782
subtype at /data/vtjnash/julia/src/subtype.c:1257
subtype_unionall at /data/vtjnash/julia/src/subtype.c:782
subtype at /data/vtjnash/julia/src/subtype.c:1257
exists_subtype at /data/vtjnash/julia/src/subtype.c:1396 [inlined]
forall_exists_subtype at /data/vtjnash/julia/src/subtype.c:1432
ijl_subtype_env at /data/vtjnash/julia/src/subtype.c:1894
jl_f_issubtype at /data/vtjnash/julia/src/builtins.c:509
⊑ at ./compiler/abstractlattice.jl:142 [inlined]
⊑ at ./compiler/typelattice.jl:505
⊑ at ./compiler/typelattice.jl:483
⊑ at ./compiler/typelattice.jl:407 [inlined]
⊑ at ./compiler/typelattice.jl:377 [inlined]
#344 at ./compiler/abstractlattice.jl:190 [inlined]
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:170
...

with values

x = NamedTuple{(:src, :tgt, :in_src, :in_tgt, :out_src, :out_tgt, :pass_src, :pass_tgt, :in_port_box, :out_port_box, :in_port_type, :out_port_type, :outer_in_port_type, :outer_out_port_type, :value, :box_type, :wire_value, :in_wire_value, :out_wire_value, :pass_wire_value), Tuple{Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseColumn{PortValue, Array{Union{Nothing, PortValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{PortValue, Array{Union{Nothing, PortValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{PortValue, Array{Union{Nothing, PortValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{PortValue, Array{Union{Nothing, PortValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{Union{Catlab.WiringDiagrams.DirectedWiringDiagrams.AbstractBox, BoxValue}, Array{Union{Nothing, Catlab.WiringDiagrams.DirectedWiringDiagrams.AbstractBox, BoxValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{DataType, Array{Union{Nothing, DataType}, 1}}, Catlab.ColumnImplementations.DenseColumn{WireValue, Array{Union{Nothing, WireValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{WireValue, Array{Union{Nothing, WireValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{WireValue, Array{Union{Nothing, WireValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{WireValue, Array{Union{Nothing, WireValue}, 1}}}} where BoxValue where WireValue where PortValue

and

y = Union{Catlab.LVectors.LVector{(:Box, :InPort, :OutPort, :OuterInPort, :OuterOutPort, :Wire, :InWire, :OutWire, :PassWire), Int64}, NamedTuple{(:src, :tgt, :in_src, :in_tgt, :out_src, :out_tgt, :pass_src, :pass_tgt, :in_port_box, :out_port_box, :in_port_type, :out_port_type, :outer_in_port_type, :outer_out_port_type, :value, :box_type, :wire_value, :in_wire_value, :out_wire_value, :pass_wire_value), Tuple{Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseIndexedFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseFinColumn{Array{Union{Nothing, Int64}, 1}}, Catlab.ColumnImplementations.DenseColumn{PortValue, Array{Union{Nothing, PortValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{PortValue, Array{Union{Nothing, PortValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{PortValue, Array{Union{Nothing, PortValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{PortValue, Array{Union{Nothing, PortValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{Union{Catlab.WiringDiagrams.DirectedWiringDiagrams.AbstractBox, BoxValue}, Array{Union{Nothing, Catlab.WiringDiagrams.DirectedWiringDiagrams.AbstractBox, BoxValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{DataType, Array{Union{Nothing, DataType}, 1}}, Catlab.ColumnImplementations.DenseColumn{WireValue, Array{Union{Nothing, WireValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{WireValue, Array{Union{Nothing, WireValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{WireValue, Array{Union{Nothing, WireValue}, 1}}, Catlab.ColumnImplementations.DenseColumn{WireValue, Array{Union{Nothing, WireValue}, 1}}}} where BoxValue where WireValue where PortValue}

[JeffBezanson]

Short reproducer:

T = Ref{NTuple{8, Ref{Union{Int, P}}}} where P

S = Ref{NTuple{8, Ref{Union{Int, P}}}} where P

T <: Union{Int, S}

(Need to have two "copies" of the type so we can't cheat with pointer equality.)