Missing symbols with `optimize = "false"` and `panic = "abort"`

Summary

Having optimize = "false" in bootstrap.toml causes

 = note: Undefined symbols for architecture arm64:
            "core::ptr::drop_in_place$LT$alloc..boxed..Box$LT$dyn$u20$core..any..Any$u2b$core..marker..Send$GT$$GT$::hcc3526ae516987a1", referenced from:
                std::panicking::try::cleanup::h73ac583610235009 in libstd-2e13ee922e5a6504.rlib[7](std-2e13ee922e5a6504.std.de67259d40fecdda-cgu.04.rcgu.o)
                std::rt::lang_start_internal::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::hedd318147b7d845a in libstd-2e13ee922e5a6504.rlib[18](std-2e13ee922e5a6504.std.de67259d40fecdda-cgu.15.rcgu.o)
            "alloc::boxed::Box$LT$T$C$A$GT$::from_raw_in::he9e618f702525f8b", referenced from:
                std::panicking::try::cleanup::h73ac583610235009 in libstd-2e13ee922e5a6504.rlib[7](std-2e13ee922e5a6504.std.de67259d40fecdda-cgu.04.rcgu.o)
            "alloc::boxed::Box$LT$T$C$A$GT$::into_raw::h79583d854b3b1b93", referenced from:
                _$LT$std..panicking..begin_panic_handler..FormatStringPayload$u20$as$u20$core..panic..PanicPayload$GT$::take_box::h14da0fd70b068231 in libstd-2e13ee922e5a6504.rlib[7](std-2e13ee922e5a6504.std.de67259d40fecdda-cgu.04.rcgu.o)
                _$LT$std..panicking..begin_panic_handler..StaticStrPayload$u20$as$u20$core..panic..PanicPayload$GT$::take_box::hfd105107c2b4e561 in libstd-2e13ee922e5a6504.rlib[7](std-2e13ee922e5a6504.std.de67259d40fecdda-cgu.04.rcgu.o)
          ld: symbol(s) not found for architecture arm64
          clang: error: linker command failed with exit code 1 (use -v to see invocation)

when compiling a crate with

[profile.release]
panic = 'abort'

[profile.dev]
panic = 'abort'

Command used

cargo build

Expected behaviour

No errors from the linker.

Actual behaviour

Some symbols are undefined.

Bootstrap configuration (bootstrap.toml)

[rust]
codegen-backends = ["llvm"]
debug = true
debuginfo-level = 2
optimize = false

Operating system

macOS 15.5, aarch64

HEAD

6b00bc38 (1.88.0)

Additional context

I came across this problem while using an explicitly unsupported configuration in bootstrap.toml: optimize = "false".
As such, this is not a problem, in the sense that I got what I asked for: non-obvious errors using an unsupported configuration.
As mentioned in this discussion on Zulip, however, it could be useful to see if this error indicates a deeper issue that might be worth investigating.

Start by reproducing the reported cargo build failure on macOS 15.5 aarch64 using the shown bootstrap.toml with optimize = false, codegen-backends = ["llvm"], and panic = "abort". Compare the result with a supported optimization setting and determine whether the undefined symbols indicate a deeper compiler or bootstrap issue; done means a confirmed diagnosis and a clearly scoped follow-up.