rust-1.77_beta bootstrap is broken with: error[E0658]: `c".."` literals are experimental in library/std/src/sys/pal/unix/

[stefson]

hello everyone,

I got this error when I bootstrap the current rust-beta branch:

error[E0658]: `c".."` literals are experimental
  --> library/std/src/sys/pal/unix/mod.rs:74:35
   |
74 |         thread::Thread::set_name(&c"main");
   |                                   ^^^^^^^
   |
   = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
   = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
   --> library/std/src/sys/pal/unix/mod.rs:126:27
    |
126 |                 if open64(c"/dev/null".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
    |                           ^^^^^^^^^^^^
    |
    = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
    = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
   --> library/std/src/sys/pal/unix/mod.rs:156:31
    |
156 |                     if open64(c"/dev/null".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
    |                               ^^^^^^^^^^^^
    |
    = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
    = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
   --> library/std/src/sys/pal/unix/args.rs:249:53
    |
249 |             let process_info_sel = sel_registerName(c"processInfo".as_ptr());
    |                                                     ^^^^^^^^^^^^^^
    |
    = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
    = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
   --> library/std/src/sys/pal/unix/args.rs:250:50
    |
250 |             let arguments_sel = sel_registerName(c"arguments".as_ptr());
    |                                                  ^^^^^^^^^^^^
    |
    = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
    = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
   --> library/std/src/sys/pal/unix/args.rs:251:46
    |
251 |             let count_sel = sel_registerName(c"count".as_ptr());
    |                                              ^^^^^^^^
    |
    = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
    = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
   --> library/std/src/sys/pal/unix/args.rs:252:56
    |
252 |             let object_at_index_sel = sel_registerName(c"objectAtIndex:".as_ptr());
    |                                                        ^^^^^^^^^^^^^^^^^
    |
    = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
    = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
   --> library/std/src/sys/pal/unix/args.rs:253:51
    |
253 |             let utf8string_sel = sel_registerName(c"UTF8String".as_ptr());
    |                                                   ^^^^^^^^^^^^^
    |
    = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
    = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
   --> library/std/src/sys/pal/unix/args.rs:255:39
    |
255 |             let klass = objc_getClass(c"NSProcessInfo".as_ptr());
    |                                       ^^^^^^^^^^^^^^^^
    |
    = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
    = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
    --> library/std/src/sys/pal/unix/fs.rs:1143:17
     |
1143 |                 c"".as_ptr() as *const c_char,
     |                 ^^^
     |
     = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
     = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
  --> library/std/src/sys/pal/unix/process/process_common.rs:27:33
   |
27 |         const DEV_NULL: &CStr = c"null:";
   |                                 ^^^^^^^^
   |
   = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
   = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
  --> library/std/src/sys/pal/unix/process/process_common.rs:29:33
   |
29 |         const DEV_NULL: &CStr = c"/null";
   |                                 ^^^^^^^^
   |
   = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
   = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
  --> library/std/src/sys/pal/unix/process/process_common.rs:31:33
   |
31 |         const DEV_NULL: &CStr = c"/dev/null";
   |                                 ^^^^^^^^^^^^
   |
   = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
   = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

error[E0658]: `c".."` literals are experimental
   --> library/std/src/sys/pal/unix/thread.rs:168:17
    |
168 |                 c"%s".as_ptr(),
    |                 ^^^^^
    |
    = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
    = help: add `#![feature(c_str_literals)]` to the crate attributes to enable

For more information about this error, try `rustc --explain E0658`.

Did not run successfully: exit status: 1

There was a lot of pushing and reverting changesets relevant to the c literals stabilization, I tried to get an overview of what backport might be missing here, but I failed and am at a loss.

I am on linux x86_64, with musl as my libc, I doubt the later is causing the issues.

[Noratrieb]

What are you using as your bootstrap compiler? We only support using the previous release.

[ehuss]

I think I understand what is going on. If you try to bootstrap 1.77 from 1.76, it will fail. We were intending to have c-string literals stabilized in 1.76, but that got reverted. However, the revert did not include the appropriate parts of #119211. I can probably put something together to fix it.

[ehuss]

Posted #120821 with a fix.