Unexpected Error. How would I dig deeper?

Internal error: encountered unexpected error in runtime:
BoundsError(a=Array{Core.Compiler.BasicBlock, (47,)}[Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=1, stop=9), preds=Array{Int64, (1,)}[27], succs=Array{Int64, (2,)}[3, 2]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=10, stop=11), preds=Array{Int64, (1,)}[1], succs=Array{Int64, (1,)}[4]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=12, stop=12), preds=Array{Int64, (1,)}[1], succs=Array{Int64, (1,)}[4]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=13, stop=14), preds=Array{Int64, (2,)}[2, 3], succs=Array{Int64, (2,)}[6, 5]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=15, stop=16), preds=Array{Int64, (1,)}[4], succs=Array{Int64, (0,)}[]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=17, stop=17), preds=Array{Int64, (1,)}[4], succs=Array{Int64, (1,)}[7]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=18, stop=18), preds=Array{Int64, (1,)}[6], succs=Array{Int64, (1,)}[8]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=19, stop=19), preds=Array{Int64, (1,)}[7], succs=Array{Int64, (1,)}[9]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=20, stop=20), preds=Array{Int64, (1,)}[8], succs=Array{Int64, (1,)}[10]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=21, stop=22), preds=Array{Int64, (1,)}[9], succs=Array{Int64, (1,)}[11]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=23, stop=23), preds=Array{Int64, (1,)}[10], succs=Array{Int64, (1,)}[12]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=24, stop=24), preds=Array{Int64, (1,)}[11], succs=Array{Int64, (1,)}[13]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=25, stop=35), preds=Array{Int64, (1,)}[12], succs=Array{Int64, (2,)}[30, 14]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtRange(start=36, stop=36), preds=Array{Int64, (1,)}[13], succs=Array{Int64, (1,)}[15]), Core.Compiler.BasicBlock(stmts=Core.Compiler.StmtR
jl_bounds_error_ints at /cygdrive/c/buildbot/worker/package_win64/build/src\rtutils.c:186
getindex at .\array.jl:805 [inlined]
getindex at .\abstractarray.jl:1173 [inlined]
replace_code_newstyle! at .\compiler/ssair\legacy.jl:62
finish at .\compiler\optimize.jl:228
optimize at .\compiler\optimize.jl:273 [inlined]
_typeinf at .\compiler\typeinfer.jl:244
typeinf at .\compiler\typeinfer.jl:209
typeinf_edge at .\compiler\typeinfer.jl:806
abstract_call_method at .\compiler\abstractinterpretation.jl:490
abstract_call_gf_by_type at .\compiler\abstractinterpretation.jl:143
abstract_call_known at .\compiler\abstractinterpretation.jl:1048
abstract_call at .\compiler\abstractinterpretation.jl:1071
abstract_call at .\compiler\abstractinterpretation.jl:1055
abstract_eval_statement at .\compiler\abstractinterpretation.jl:1182
typeinf_local at .\compiler\abstractinterpretation.jl:1470
typeinf_nocycle at .\compiler\abstractinterpretation.jl:1534
_typeinf at .\compiler\typeinfer.jl:214
typeinf at .\compiler\typeinfer.jl:209
typeinf_ext at .\compiler\typeinfer.jl:892
typeinf_ext_toplevel at .\compiler\typeinfer.jl:925
typeinf_ext_toplevel at .\compiler\typeinfer.jl:921
jfptr_typeinf_ext_toplevel_14355.clone_1 at C:\Users\<user>\AppData\Local\Programs\Julia-1.6.3\lib\julia\sys.dll (unknown line)
_jl_invoke at /cygdrive/c/buildbot/worker/package_win64/build/src\gf.c:2237 [inlined]
jl_apply_generic at /cygdrive/c/buildbot/worker/package_win64/build/src\gf.c:2419 [inlined]
jl_apply at /cygdrive/c/buildbot/worker/package_win64/build/src\julia.h:1703 [inlined]
jl_type_infer at /cygdrive/c/buildbot/worker/package_win64/build/src\gf.c:298
jl_generate_fptr at /cygdrive/c/buildbot/worker/package_win64/build/src\jitlayers.cpp:340
jl_compile_method_internal at /cygdrive/c/buildbot/worker/package_win64/build/src\gf.c:1970
jl_compile_method_internal at /cygdrive/c/buildbot/worker/package_win64/build/src\gf.c:1924 [inlined]
_jl_invoke at /cygdrive/c/buildbot/worker/package_win64/build/src\gf.c:2229 [inlined]
jl_apply_generic at /cygdrive/c/buildbot/worker/package_win64/build/src\gf.c:2419
jl_apply at /cygdrive/c/buildbot/worker/package_win64/build/src\julia.h:1703 [inlined]
start_task at /cygdrive/c/buildbot/worker/package_win64/build/src\task.c:833