Got error recompiling core

[kalikaruto]

nightly version

rustc 1.89.0-nightly (45acf54ee 2025-06-16)
binary: rustc
commit-hash: 45acf54eea118ed27927282b5e0bfdcd80b7987c
commit-date: 2025-06-16
host: x86_64-unknown-linux-gnu
release: 1.89.0-nightly
LLVM version: 20.1.5

my system

• os: archlinux
• de: kde

the error i got

cargo build --target x86_64-karutos.json
    Updating crates.io index
  Downloaded rustc-literal-escaper v0.0.2
  Downloaded addr2line v0.25.0
  Downloaded getopts v0.2.23
  Downloaded rustc-demangle v0.1.25
  Downloaded hashbrown v0.15.4
  Downloaded unicode-width v0.2.1
  Downloaded gimli v0.32.0
  Downloaded object v0.37.1
  Downloaded 8 crates (1.1MiB) in 0.87s
   Compiling compiler_builtins v0.1.160 (/home/karuto/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/compiler-builtins/compiler-builtins)
   Compiling core v0.0.0 (/home/karuto/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core)
error: implementation must be applied to type that has the same ABI as a pointer, or is `repr(transparent)` and whose field is `PointerLike`
    --> /home/karuto/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/marker.rs:56:26
     |
56   |           $(#[$($meta)*])* impl< $($($bounds)*)? > $Trait for $T {}
     |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
1048 | / marker_impls! {
1049 | |     #[unstable(feature = "pointer_like_trait", issue = "none")]
1050 | |     PointerLike for
1051 | |         isize,
...    |
1057 | |         {T: PointerLike} crate::pin::Pin<T>,
1058 | | }
     | |_- in this macro invocation
     |
     = note: only user-defined sized types are eligible for `impl PointerLike`
     = note: this error originates in the macro `marker_impls` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0527]: pattern requires 0 elements but array has 4
    --> /home/karuto/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/sync/atomic.rs:2760:21
     |
2760 |                   let [] = [(); align_of::<Self>() - align_of::<$int_type>()];
     |                       ^^ expected 4 elements
...
3908 | / atomic_int_ptr_sized! {
3909 | |     "16" 2
3910 | |     "32" 4
3911 | |     "64" 8
3912 | | }
     | |_- in this macro invocation
     |
     = note: this error originates in the macro `atomic_int` which comes from the expansion of the macro `atomic_int_ptr_sized` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0527]: pattern requires 0 elements but array has 4
    --> /home/karuto/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/sync/atomic.rs:2827:21
     |
2827 |                   let [] = [(); align_of::<Self>() - align_of::<$int_type>()];
     |                       ^^ expected 4 elements
...
3908 | / atomic_int_ptr_sized! {
3909 | |     "16" 2
3910 | |     "32" 4
3911 | |     "64" 8
3912 | | }
     | |_- in this macro invocation
     |
     = note: this error originates in the macro `atomic_int` which comes from the expansion of the macro `atomic_int_ptr_sized` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0527`.
error: could not compile `core` (lib) due to 6 previous errors

Is there any specific version which i should use for this (in the blog it says Note: The unstable.build-std configuration key requires at least the Rust nightly from 2020-07-15.)

[ChocolateLoverRaj]

Try using --target x86_64-unknown-none instead of your custom target.

[kalikaruto]

That worked but I want follow the post-02 exactly is there any particular version which works with the custom target File in post-02.

[ChocolateLoverRaj]

Don't worry, using x86_64-unknown-none will not cause issues with following the rest of the tutorial. When edition 2 was made, it wasn't a target so a custom target was necessary. I don't know which nightly version was used when edition 2 was made. Even if using the latest nightly has a few inconsistencies with the tutorial, it isn't that hard to make some small changes for it to work with the latest nightly compiler.

[kalikaruto]

Is there any difference then between cargo build --target thumbv7em-none-eabihf and cargo build --target x86_64-unknown-none. And i get it that --target x86_64-unknown-none will work but please can i still know how i can recompile core crate without any errors; i want to debug it for my understanding.

[ChocolateLoverRaj]

thumbv7em-none-eabihf is arm, so it won't work for this x86_64 tutorial. I think there are other issues / discussions here that show how to update the custom target json for the latest Rust. I haven't done that personally so idk.

[kalikaruto]

cargo build --target thumbv7em-none-eabihf compiled though without any errors; and i will read those discussions but would you recommend i tweak the code and debug it; would doing this break anything

ps: i am extremely new to rust;