can't find crate for core

[kacper-cholewinski]

I get this error when trying to compile:
error[E0463]: can't find crate for core
|
= note: the avr-atmega328p target may not be installed
= help: consider downloading the target with rustup target add avr-atmega328p

Working with freshly generated project, using cargo-generate and provided template.

Any help would be appreciated.

[stappersg]

On Wed, Apr 17, 2024 at 11:41:33AM -0700, Kacper Cholewiński wrote: I get this error when trying to compile: error[E0463]: can't find crate for `core` | = note: the `avr-atmega328p` target may not be installed = help: consider downloading the target with `rustup target add avr-atmega328p` Working with freshly generated project, using cargo-generate and provided template.

`rustup target add avr-atmega328p`

Any help would be appreciated.

Provide feedback

[kacper-cholewinski]

Well, every avr target is custom made json, so it doesn't work with rustup target add

[Rahix]

Hm, not finding core sounds like build-std is not active. There should be a configuration file .cargo/config.toml with the following lines:

avr-hal/examples/arduino-uno/.cargo/config.toml

Lines 9 to 10 in 7f7d0a5

	[unstable]
	build-std = ["core"]

This tells cargo to build core for your specific target.

What version of cargo and rustc are you using?

[stappersg]

What version of cargo and rustc are you using?

And I would like to known additional information how to reproduce the error. Not for the error, but for solving the error.

[kacper-cholewinski]

What version of cargo and rustc are you using?

cargo --version: cargo 1.77.2 (e52e36006 2024-03-26)
rustc --version: rustc 1.77.2 (25ef9e3d8 2024-04-09)
rustup --version:

rustup 1.27.0 (bbb9276d2 2024-03-08)
info: This is the version for the rustup toolchain manager, not the rustc compiler.
info: The currently active `rustc` version is `rustc 1.79.0-nightly (0ad927c0c 2024-03-21)`

rustup toolchain list:

stable-x86_64-pc-windows-msvc
nightly-2023-08-08-x86_64-pc-windows-msvc
nightly-2024-03-22-x86_64-pc-windows-msvc (override)
nightly-x86_64-pc-windows-msvc (default)

There is build-std = ["core"] present in my config.toml.

And I would like to known additional information how to reproduce the error.

There is not much to reproduce - I generated new project from template, for Arduino Uno, and used cargo run inside.

There is one thing that could be significant - I recently cleared my PATH env variable by accident, but I added .../.cargo/bin back, and it still doesn't work. Maybe there is some other path that I should add there again?

[Rahix]

Hmm, can these numbers don't quite add up... Did you run all the .. --version commands inside the project directory? What are the contents of your rust-toolchain.toml?

[kacper-cholewinski]

Did you run all the .. --version commands inside the project directory?

Yep.

Hmm, can these numbers don't quite add up...

Well, it looks like rustc and cargo show latest stable release version, but below you can see that rust-toolchain.toml override works.

What are the contents of your rust-toolchain.toml?

Here you go:

[toolchain]
channel = "nightly-2024-03-22"
components = ["rust-src"]
profile = "minimal"

[Rahix]

I'd expect to see this:

rustc 1.79.0-nightly (0ad927c0c 2024-03-21)
cargo 1.79.0-nightly (d438c80c4 2024-03-19)

Are you sure your rustc/cargo binaries are managed by rustup? Does

rustc +nightly-2024-03-22 --version

work or do you get an error?

[kacper-cholewinski]

Well, this is weird...
rustc +nightly-2024-03-22 --version: rustc 1.77.2 (25ef9e3d8 2024-04-09)

[Rahix]

My best guess is that your rustup installation is broken in some way... Maybe delete all toolchains, reinstall rustup, and see if the problem persists. Or ask rustup upstream about it...

[kacper-cholewinski]

Maybe delete all toolchains, reinstall rustup, and see if the problem persists.

Well, I did it, and everything works now.
Weird thing is, this was actually second time I reinstalled everything, after problem occured for the first time. Only difference is, I've chosen "complete" installation instead of "default" (in rustup installer for Windows). I also noticed that now rustup installed all of the components for given nightly version, not only "rust-src" like before. This way all my rustc, cargo, etc. versions are synchronized now.

Thanks for all your help, I appreciate it.

[stappersg]

Thanks for all your help, I appreciate it.

And thank you for the provided feedback.

What about closing this issue? If it should remain open, express for which reason.

Karma bonus points for "comment and close" with a text like:

On Microsoft windows version 9 installed Rust as advised for windows, cargo install cargo-generate, more notes, cargo generate URL-to-template projectname, cd projectname and cargo run worked for me on 2024-04-21.