Illegal instruction on 1.8.5 with varargs

[ericphanson]

               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
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   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.8.5 (2023-01-08)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
|__/                   |

julia> function f(xs...=["a", "b", "c"]...; debug=false)
           return xs[1]
       end
f (generic function with 2 methods)

julia> f()
"a"

julia> f(; debug=false)
Unreachable reached at 0x7fd84373a5b6

signal (4): Illegal instruction
in expression starting at REPL[3]:1
f##kw at ./REPL[1]:1
unknown function (ip: 0x7fd84373a60d)
_jl_invoke at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/gf.c:2377 [inlined]
ijl_apply_generic at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/gf.c:2559
jl_apply at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/julia.h:1843 [inlined]
do_call at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/interpreter.c:126
eval_value at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/interpreter.c:215
eval_stmt_value at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/interpreter.c:166 [inlined]
eval_body at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/interpreter.c:612
jl_interpret_toplevel_thunk at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/interpreter.c:750
jl_toplevel_eval_flex at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/toplevel.c:906
jl_toplevel_eval_flex at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/toplevel.c:850
jl_toplevel_eval_flex at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/toplevel.c:850
ijl_toplevel_eval_in at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/toplevel.c:965
eval at ./boot.jl:368 [inlined]
eval_user_input at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/usr/share/julia/stdlib/v1.8/REPL/src/REPL.jl:151
repl_backend_loop at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/usr/share/julia/stdlib/v1.8/REPL/src/REPL.jl:247
start_repl_backend at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/usr/share/julia/stdlib/v1.8/REPL/src/REPL.jl:232
#run_repl#47 at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/usr/share/julia/stdlib/v1.8/REPL/src/REPL.jl:369
run_repl at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/usr/share/julia/stdlib/v1.8/REPL/src/REPL.jl:355
jfptr_run_repl_65104.clone_1 at /home/ubuntu/.julia/juliaup/julia-1.8.5+0.x64.linux.gnu/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/gf.c:2377 [inlined]
ijl_apply_generic at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/gf.c:2559
#967 at ./client.jl:419
jfptr_YY.967_33139.clone_1 at /home/ubuntu/.julia/juliaup/julia-1.8.5+0.x64.linux.gnu/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/gf.c:2377 [inlined]
ijl_apply_generic at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/gf.c:2559
jl_apply at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/julia.h:1843 [inlined]
jl_f__call_latest at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/builtins.c:774
#invokelatest#2 at ./essentials.jl:729 [inlined]
invokelatest at ./essentials.jl:726 [inlined]
run_main_repl at ./client.jl:404
exec_options at ./client.jl:318
_start at ./client.jl:522
jfptr__start_38041.clone_1 at /home/ubuntu/.julia/juliaup/julia-1.8.5+0.x64.linux.gnu/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/gf.c:2377 [inlined]
ijl_apply_generic at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/gf.c:2559
jl_apply at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/julia.h:1843 [inlined]
true_main at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/jlapi.c:575
jl_repl_entrypoint at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/src/jlapi.c:719
main at /cache/build/default-amdci4-2/julialang/julia-release-1-dot-8/cli/loader_exe.c:59
__libc_start_main at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
unknown function (ip: 0x401098)
Allocations: 2043817 (Pool: 2042285; Big: 1532); GC: 2
[1]    1759237 illegal hardware instruction (core dumped)  julia

on

Julia Version 1.8.5
Commit 17cfb8e65ea (2023-01-08 06:45 UTC)
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 8 × AMD EPYC 7R13 Processor
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-13.0.1 (ORCJIT, znver3)
  Threads: 1 on 8 virtual cores
Environment:
  JULIA_PKG_USE_CLI_GIT = true

[ericphanson]

On apple silicon, w/ Julia 1.8 and 1.9, this just seems to hang rather than crash.

[inkydragon]

Also confirmed in

• Version 1.6.7, test on Win10 and Ubuntu 22.04.2
• Version 1.10.0-alpha1, DEBUG build with assert
  Printed a similar stack trace.

[Keno]

There's a couple of separate issues here:

1. The xs...=["a", "b", "c"]... was never really supposed to work and only works by accident. @JeffBezanson thinks the syntax is reasonable for what is intended, but we need to decide where the boundaries of the syntax are.

1a. For example, what should the following do?

julia> function g(a=(1,2)..., b...=3)
           b
       end
g (generic function with 3 methods)

julia> g()
(2,)

2. The lowering for that syntax in the keyword case is bad and uses an argument marked #unused#

3. Even though we're using #unused#, we should be robust to that elsewhere (in particular lowering and codegen) to avoid a segfault.

[Keno]

#50556 for issue 3.

[Keno]

#50559 for issue 2.

[Keno]

#50563 for issue 1.