`rustc --print=sysroot` gives SIGSEGV on nightly

[Zeophlite]

❯ rustc --print=sysroot                                                                                                                ─╯
error: rustc interrupted by SIGSEGV, printing backtrace

0   librustc_driver-5f16f2e67e217845.dy 0x00000001086e5ecc _RNvNtCsenXWW04bcaD_17rustc_driver_impl14signal_handler17print_stack_trace + 140
1   libsystem_platform.dylib            0x000000018d231744 _sigtramp + 56
2   libLLVM.dylib                       0x00000001169aa33c _ZNK4llvm15MCSubtargetInfo13checkFeaturesENS_9StringRefE + 40
3   librustc_driver-5f16f2e67e217845.dy 0x000000010a9c614c LLVMRustHasFeature + 104
4   librustc_driver-5f16f2e67e217845.dy 0x0000000108384984 _RNvXs3_Cskq7p8hWEhoI_18rustc_codegen_llvmNtB5_18LlvmCodegenBackendNtNtNtCslJdscGbVbSf_17rustc_codegen_ssa6traits7backend14CodegenBackend13target_config + 492
5   librustc_driver-5f16f2e67e217845.dy 0x00000001086ceb90 _RNCINvNtCs332zhQV777G_15rustc_interface9interface12run_compileruNCNvCsenXWW04bcaD_17rustc_driver_impl12run_compiler0Es0_0B14_ + 1152
6   librustc_driver-5f16f2e67e217845.dy 0x00000001086c1350 _RINvNtNtCshaMuUdr4xqv_3std3sys9backtrace28___rust_begin_short_backtraceNCNCINvNtCs332zhQV777G_15rustc_interface4util26run_in_thread_with_globalsNCINvB1e_31run_in_thread_pool_with_globalsNCINvNtB1g_9interface12run_compileruNCNvCsenXWW04bcaD_17rustc_driver_impl12run_compiler0Es0_0uE0uE00uEB3C_ + 308
7   librustc_driver-5f16f2e67e217845.dy 0x00000001086d5580 _RNSNvYNCINvNtNtCshaMuUdr4xqv_3std6thread9lifecycle15spawn_uncheckedNCNCINvNtCs332zhQV777G_15rustc_interface4util26run_in_thread_with_globalsNCINvB1a_31run_in_thread_pool_with_globalsNCINvNtB1c_9interface12run_compileruNCNvCsenXWW04bcaD_17rustc_driver_impl12run_compiler0Es0_0uE0uE00uEs_0INtNtNtCsbdgPRJL8iXf_4core3ops8function6FnOnceuE9call_once6vtableB3y_ + 184
8   librustc_driver-5f16f2e67e217845.dy 0x000000010a903f34 _RNvNvMs0_NtNtNtCshaMuUdr4xqv_3std3sys6thread4unixNtB7_6Thread3new12thread_start + 384
9   libsystem_pthread.dylib             0x000000018d227c58 _pthread_start + 136
10  libsystem_pthread.dylib             0x000000018d222c1c thread_start + 8

note: we would appreciate a report at https://github.com/rust-lang/rust
[1]    63290 segmentation fault  rustc --print=sysroot

Meta

rustc --version --verbose:

rustc 1.100.0-nightly (17fd5b8a3 2026-08-28)
binary: rustc
commit-hash: 17fd5b8a37b6667b6cc137f3cc35f09759768a3b
commit-date: 2026-08-28
host: aarch64-apple-darwin
release: 1.100.0-nightly
LLVM version: 23.1.0

This is on Apple M1 Pro (26.6.2)

(Note: same issue after rustup update to fd7ed57df 2026-08-29 )

[fmease]

Can anybody else with a similar environment confirm this?

[jnkel]

That stack trace looks like an LLVM version mismatch. rustc recently updated to LLVM 23, but your compiler is running against LLVM 22 for some reason.

Can you show your environment? Perhaps you have a dyld environment variable forcing rustc to load an incorrect LLVM version; I can reproduce a similar crash if I set DYLD_LIBRARY_PATH to a copy of LLVM 22 I have installed through Homebrew.

I have an open PR to give a better error message in this situation: #161788