"bpart: Start tracking backedges for bindings" introduced UB into our CI

[vtjnash]

As mentioned in the comment during PR review, this PR is causing CI crashes due to the introduction of UB / memory corruption here: #57213 (review)

Internal error: during type inference of
2025-02-17 18:10:36 EST	var"#create_tasks##3"()
2025-02-17 18:10:36 EST	Encountered unexpected error in runtime:
2025-02-17 18:10:36 EST	UndefRefError()
2025-02-17 18:10:36 EST	getindex at ./essentials.jl:918 [inlined]
2025-02-17 18:10:36 EST	maybe_add_binding_backedge! at ./invalidation.jl:173
2025-02-17 18:10:36 EST	store_backedges at ./../usr/share/julia/Compiler/src/typeinfer.jl:561
2025-02-17 18:10:36 EST	codeinst_as_edge at ./../usr/share/julia/Compiler/src/typeinfer.jl:839
2025-02-17 18:10:36 EST	const_prop_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:1370
2025-02-17 18:10:36 EST	abstract_call_method_with_const_args at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:911
2025-02-17 18:10:36 EST	abstract_call_method_with_const_args at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:881 [inlined]
2025-02-17 18:10:36 EST	handle1 at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:178
2025-02-17 18:10:36 EST	infercalls at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:252
2025-02-17 18:10:36 EST	abstract_call_gf_by_type at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:345
2025-02-17 18:10:36 EST	abstract_call_known at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2769
2025-02-17 18:10:36 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2876
2025-02-17 18:10:36 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2869 [inlined]
2025-02-17 18:10:36 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3029
2025-02-17 18:10:36 EST	abstract_eval_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3047 [inlined]
2025-02-17 18:10:36 EST	abstract_eval_statement_expr at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3354
2025-02-17 18:10:36 EST	typeinf_local at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:4106
2025-02-17 18:10:36 EST	jfptr_typeinf_local_126997 at /cache/build/tester-amdci5-9/julialang/julia-master/julia-7c89aba267/lib/julia/sys.so (unknown line)
2025-02-17 18:10:36 EST	_jl_invoke at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3456 [inlined]
2025-02-17 18:10:36 EST	ijl_apply_generic at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3675
2025-02-17 18:10:36 EST	typeinf at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:4298
2025-02-17 18:10:36 EST	const_prop_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:1361
2025-02-17 18:10:36 EST	abstract_call_method_with_const_args at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:911
2025-02-17 18:10:36 EST	abstract_call_method_with_const_args at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:881 [inlined]
2025-02-17 18:10:36 EST	handle1 at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:178
2025-02-17 18:10:36 EST	infercalls at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:252
2025-02-17 18:10:36 EST	abstract_call_gf_by_type at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:345
2025-02-17 18:10:36 EST	abstract_call_known at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2769
2025-02-17 18:10:36 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2876
2025-02-17 18:10:37 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2869 [inlined]
2025-02-17 18:10:37 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3029
2025-02-17 18:10:37 EST	abstract_eval_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3047 [inlined]
2025-02-17 18:10:37 EST	abstract_eval_statement_expr at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3354
2025-02-17 18:10:37 EST	typeinf_local at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:4106
2025-02-17 18:10:37 EST	jfptr_typeinf_local_126997 at /cache/build/tester-amdci5-9/julialang/julia-master/julia-7c89aba267/lib/julia/sys.so (unknown line)
2025-02-17 18:10:37 EST	_jl_invoke at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3456 [inlined]
2025-02-17 18:10:37 EST	ijl_apply_generic at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3675
2025-02-17 18:10:37 EST	typeinf at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:4298
2025-02-17 18:10:37 EST	const_prop_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:1361
2025-02-17 18:10:37 EST	abstract_call_method_with_const_args at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:911
2025-02-17 18:10:37 EST	abstract_call_method_with_const_args at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:881 [inlined]
2025-02-17 18:10:37 EST	handle1 at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:178
2025-02-17 18:10:37 EST	infercalls at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:252
2025-02-17 18:10:37 EST	abstract_call_gf_by_type at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:345
2025-02-17 18:10:37 EST	abstract_call_known at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2769
2025-02-17 18:10:37 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2876
2025-02-17 18:10:37 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2869 [inlined]
2025-02-17 18:10:37 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3029
2025-02-17 18:10:37 EST	abstract_eval_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3047 [inlined]
2025-02-17 18:10:37 EST	abstract_eval_statement_expr at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3354
2025-02-17 18:10:37 EST	typeinf_local at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:4106
2025-02-17 18:10:37 EST	jfptr_typeinf_local_126997 at /cache/build/tester-amdci5-9/julialang/julia-master/julia-7c89aba267/lib/julia/sys.so (unknown line)
2025-02-17 18:10:37 EST	_jl_invoke at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3456 [inlined]
2025-02-17 18:10:37 EST	ijl_apply_generic at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3675
2025-02-17 18:10:37 EST	typeinf at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:4298
2025-02-17 18:10:37 EST	const_prop_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:1361
2025-02-17 18:10:37 EST	abstract_call_method_with_const_args at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:911
2025-02-17 18:10:37 EST	abstract_call_method_with_const_args at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:881 [inlined]
2025-02-17 18:10:37 EST	handle1 at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:178
2025-02-17 18:10:37 EST	infercalls at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:252
2025-02-17 18:10:37 EST	abstract_call_gf_by_type at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:345
2025-02-17 18:10:37 EST	abstract_call_known at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2769
2025-02-17 18:10:37 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2876
2025-02-17 18:10:37 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:2869 [inlined]
2025-02-17 18:10:37 EST	abstract_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3029
2025-02-17 18:10:37 EST	abstract_eval_call at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3047 [inlined]
2025-02-17 18:10:37 EST	abstract_eval_statement_expr at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:3354
2025-02-17 18:10:37 EST	typeinf_local at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:4106
2025-02-17 18:10:37 EST	jfptr_typeinf_local_126997 at /cache/build/tester-amdci5-9/julialang/julia-master/julia-7c89aba267/lib/julia/sys.so (unknown line)
2025-02-17 18:10:37 EST	_jl_invoke at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3456 [inlined]
2025-02-17 18:10:37 EST	ijl_apply_generic at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3675
2025-02-17 18:10:37 EST	typeinf at ./../usr/share/julia/Compiler/src/abstractinterpretation.jl:4298
2025-02-17 18:10:37 EST	typeinf_ext at ./../usr/share/julia/Compiler/src/typeinfer.jl:1166
2025-02-17 18:10:37 EST	typeinf_ext_toplevel at ./../usr/share/julia/Compiler/src/typeinfer.jl:1240
2025-02-17 18:10:37 EST	jfptr_typeinf_ext_toplevel_126802 at /cache/build/tester-amdci5-9/julialang/julia-master/julia-7c89aba267/lib/julia/sys.so (unknown line)
2025-02-17 18:10:37 EST	_jl_invoke at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3456 [inlined]
2025-02-17 18:10:37 EST	ijl_apply_generic at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3675
2025-02-17 18:10:37 EST	jl_apply at /cache/build/tester-amdci4-10/julialang/julia-master/src/julia.h:2303 [inlined]
2025-02-17 18:10:37 EST	jl_type_infer at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:453
2025-02-17 18:10:37 EST	jl_compile_method_internal at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:2972
2025-02-17 18:10:37 EST	_jl_invoke at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3467 [inlined]
2025-02-17 18:10:37 EST	ijl_apply_generic at /cache/build/tester-amdci4-10/julialang/julia-master/src/gf.c:3675
2025-02-17 18:10:37 EST	jl_apply at /cache/build/tester-amdci4-10/julialang/julia-master/src/julia.h:2303 [inlined]
2025-02-17 18:10:37 EST	start_task at /cache/build/tester-amdci4-10/julialang/julia-master/src/task.c:1249

https://buildkite.com/julialang/julia-master/builds/44900#019515d0-adde-4706-837c-2590e6b36c8b

[nsajko]

More examples:

• https://buildkite.com/julialang/julia-master/builds/45511#0195679a-de1e-4565-9590-8f8e8a331c15/893-1405
• https://buildkite.com/julialang/julia-master/builds/45540#01956c65-6f53-438d-85ad-8c566885681e/890-1409