Useful Rust macros

Rust macros are a great feature that can reduce code boilerplate and be a time saver for programmers. They also offer flexibility for developers to use metaprogramming to add new features to the language and package them in a way that is easy to integrate into code.

Is it possible to use Diesel schema macros with Rust 2018?

Diesel seems to be the only real database abstraction layer that is in a real state of completion. The problem is, though, following their guide (even when using new package import style) just results in missing macro errors for the generated schema file. After adding the «public» macro use statements, I just get more missing errors for «private» macros.

Is there any practical way of using Diesel with (stable) Rust 2018, or do I just have to wait for their next major release to be able to use Diesel?

Simplifing mathematical formulas with rust macros

How to simplify mathematical formulas with rust macros?