[BUG] Compiler crash on the last use of a bytes slice

[JuniMay]

Bug description

The compiler failed to compile the code and crashed with segmentation fault.

Steps to reproduce

• Include relevant code snippet or link to code that did not work as expected.
• If applicable, add screenshots to help explain the problem.
• If using the Playground, name the pre-existing notebook that failed and the steps that led to failure.
• Include anything else that might help us debug the issue.

The code is as below:

fn main():
    var s = String("Hello, World!")
    var b_slice = s.as_bytes_slice()
    _ = b_slice

And the compiler crashed with the backtrace below:

Please submit a bug report to https://github.com/modularml/mojo/issues and include the crash backtrace along with all the relevant source codes.
Stack dump:
0.      Program arguments: mojo main.mojo
 #0 0x000000010458a198 llvm_strlcpy (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1000be198)
 #1 0x0000000104588484 llvm_strlcpy (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1000bc484)
 #2 0x000000010458a838 llvm_strlcpy (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1000be838)
 #3 0x000000018a9fb584 (/usr/lib/system/libsystem_platform.dylib+0x180477584)
 #4 0x00000001056a3b40 __MIG_check__Request__mach_notify_dead_name_t (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1011d7b40)
 #5 0x00000001056a33b8 __MIG_check__Request__mach_notify_dead_name_t (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1011d73b8)
 #6 0x000000010569d554 __MIG_check__Request__mach_notify_dead_name_t (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1011d1554)
 #7 0x0000000105693cdc __MIG_check__Request__mach_notify_dead_name_t (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1011c7cdc)
 #8 0x0000000105b05994 mbedtls_version_get_number (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x101639994)
 #9 0x0000000105b063cc mbedtls_version_get_number (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10163a3cc)
#10 0x0000000105b090a8 mbedtls_version_get_number (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10163d0a8)
#11 0x0000000104e179bc __MIG_check__Request__mach_notify_dead_name_t (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10094b9bc)
#12 0x000000010495a508 __jit_debug_register_code (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10048e508)
#13 0x0000000104e17518 __MIG_check__Request__mach_notify_dead_name_t (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10094b518)
#14 0x0000000104e17048 __MIG_check__Request__mach_notify_dead_name_t (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10094b048)
#15 0x0000000105bf9730 mbedtls_version_get_number (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10172d730)
#16 0x0000000105bf8204 mbedtls_version_get_number (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10172c204)
#17 0x000000010492158c __jit_debug_register_code (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10045558c)
#18 0x00000001044e9f64 _mh_execute_header (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10001df64)
#19 0x00000001044d316c _mh_execute_header (/Users/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x10000716c)
#20 0x000000018a6420e0 
mojo crashed!
Please file a bug report.
[27792:18069029:20240527,105333.758524:WARNING in_range_cast.h:38] value -634136515 out of range
[27792:18069029:20240527,105333.855050:WARNING crash_report_exception_handler.cc:257] UniversalExceptionRaise: (os/kern) failure (5)
[1]    27790 segmentation fault  mojo main.mojo

Also tried the snippet on Ubuntu 23.10 VM with OrbStack, the backtrace is as below:

Please submit a bug report to https://github.com/modularml/mojo/issues and include the crash backtrace along with all the relevant source codes.
 #0 0x0000aaaae5f57c7c (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1247c7c)
 #1 0x0000aaaae5f55d18 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1245d18)
 #2 0x0000aaaae5f58380 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1248380)
 #3 0x0000ffff91559860 (linux-vdso.so.1+0x860)
 #4 0x0000aaaae6400a8c (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x16f0a8c)
 #5 0x0000aaaae707e18c (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x236e18c)
 #6 0x0000aaaae707d6d0 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x236d6d0)
 #7 0x0000aaaae7077894 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x2367894)
 #8 0x0000aaaae706e558 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x235e558)
 #9 0x0000aaaae745ac84 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x274ac84)
#10 0x0000aaaae745e400 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x274e400)
#11 0x0000aaaae67e664c (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1ad664c)
#12 0x0000aaaae630ff24 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x15fff24)
#13 0x0000aaaae67e6254 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1ad6254)
#14 0x0000aaaae67e5e64 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x1ad5e64)
#15 0x0000aaaae752982c (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x281982c)
#16 0x0000aaaae7529714 (/home/juni/.modular/pkg/packages.modular.com_nightly_mojo/bin/mojo+0x2819714)
#17 0x0000ffff910db1cc (/lib/aarch64-linux-gnu/libstdc++.so.6+0xdb1cc)
#18 0x0000ffff90ec37d0 (/lib/aarch64-linux-gnu/libc.so.6+0x837d0)
#19 0x0000ffff90f2f5cc (/lib/aarch64-linux-gnu/libc.so.6+0xef5cc)
mojo crashed!
Please file a bug report.
Segmentation fault

However, the two snippets below compiles:

fn main():
    var s = String("Hello, World!")
    var b_slice = s.as_bytes_slice()
    _ = b_slice^

fn main():
    var s = String("Hello, World!")
    var b_slice = s.as_bytes_slice()
    _ = b_slice

    var b = b_slice[0]
    _ = b

System information

- What OS did you do install Mojo on ?

macOS Sonoma 14.5 on a MacBook Pro M2 Max (Silicon)

Also tried on Ubuntu 23.10 arm64 (with OrbStack)

- Provide version information for Mojo by pasting the output of `mojo -v`

mojo 2024.5.2605 (9c328b12)

- Provide Modular CLI version by pasting the output of `modular -v`

modular 0.8.0 (39a426b5)
modular 0.7.4 (df7a9e8b) on Ubuntu 23.10 VM

[ematejska]

@ConnorGray I think you added this recently. Anything you can think of here?