Allow producing warnings at compile-time

[asterite]

Problem

Right now one can use assert, assert_eq and panic (which uses assert under the hood) to produce errors at compile-time. However, there's no equivalent to produce warnings.

Happy Case

There's a way to produce warnings at compile-time.

There could be this function in the stdlib:

#[builtin(warn)]
pub comptime fn warn<T, let N: u32>(message: fmtstr<N, T>) {}

Workaround

None

Workaround Description

No response

Additional Context

No response

Project Impact

None

Blocker Context

No response

Would you like to submit a PR for this Issue?

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Support Needs

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[TomAFrench]

https://doc.rust-lang.org/proc_macro/struct.Diagnostic.html

Something to consider when designing this.