Unable to use validation in no-std crate

[TheBestTvarynka]

Hi,
I'm trying to write a small new type struct with a simple validation in the no-std crate. My current code looks like this:

#[nutype(
    validate(less = 13),
    derive(Debug, Clone, PartialEq, Eq)
)]
pub struct Month(u8);

But unfortunately, I got the following error:

error[E0433]: failed to resolve: could not find `std` in the list of imported crates
  --> src/lib.rs:7:1
   |
7  | / #[nutype(
8  | |     validate(less = 100),
9  | |     derive(Debug, Clone, PartialEq, Eq)
10 | | )]
   | |__^ could not find `std` in the list of imported crates
   |
   = help: consider importing one of these items:
           crate::__nutype_private_Year__::core::error
           core::error
   = note: this error originates in the attribute macro `nutype` (in Nightly builds, run with -Z macro-backtrace for more info)

Is it a bug or just expected behavior?

Thanks in advance

[greyblake]

@TheBestTvarynka Thanks for the report.

Generally I tried to use ::core as much as possible instead of ::std but I did not test it for real with no-std.
I think supporting no-std should be possible with a bit of work / tuning.

[greyblake]

@TheBestTvarynka I just published 0.4.1-beta.1, please give it a try.
Note:

• String type is still not supported in no_std environment.
• Use default-features = false for nutype dependency

[TheBestTvarynka]

@greyblake yes, it works now. thank you