use of undeclared crate or module ufmt

[MLackner]

Hi!

Throughout the examples

ufmt::writeln!(&mut serial, ...);

is used. If I do that I'm not able to compile and I get the following error:

48 |     ufmt::uwriteln!(&mut serial, "Hello from Arduino!\r").void_unwrap();
   |     ^^^^ use of undeclared crate or module `ufmt`

I tried to add ufmt under [dependencies] in the Cargo.toml as ufmt = "0.1.0". Doing so gives me access to the ufmt crate with use ufmt;. The code then compiles (although rust-analyzer in VSCode complains that it could not resolve macro `ufmt::uwriteln` ).

Is this how it is intended to work? Would be great if someone could help me with that! :)

[Rahix]

Hey!

Yes, you need to add ufmt as a dependency to make this work. I guess the documentation should be more clear on that ...

Why rust-analyzier is failing, I have no idea. I'm also using it and did not see any such problems so far. Can you get a more verbose output of what it is complaining about?

[nbigaouette]

I have the same issue regarding rust-analyzer. Here's my repo: https://github.com/nbigaouette/robot-car/tree/343b89bc397dc99761de583d744ebe8d47dfd135/rust

I can cargo build and flash to my arduino uno (thanks for avr-hal!!) but rust-analyzer cannot find ufmt:

My guess is that rust-analyzer is confused with the target?

[nbigaouette]

I've reported the rust-analyzer issue upstream: rust-lang/rust-analyzer#7674

[nbigaouette]

Turns out that ufmt uses proc-macro-hack which rust-analyzer does not supports... 🤷

[Rahix]

Okay, as this is not really something related to avr-hal and there is an upstream report now, I'll close this issue here.