Best of 2025

The blog posts Hacker News loved most in 2025. 1,747 posts.

Software Engineering
844

Test, don't just verify

AI-assisted mechnical proving companies are raising funds on billion dollar valuations , new people are trying proof assistants, overwhelmingly Lean, at unprecedented rates. Models achieve fascinating results in competitions previously considered to contain some of the hardest problems in the world, such as IMO, ICPC…

857

Writing memory efficient C structs

A struct in C is the best way to organize your data so that you can easily use the data later in your program. However, there are a few caveats to C structures, mainly how their memory works. Note that I’m making a lot of assumptions about type sizes and standards. These can differ between systems and ABI’s, so for…

870

Weird Expressions in Rust

Rust has a very powerful type system, but as a result it has some quirks, some would say cursed expressions. There’s a test file, weird-expr.rs , in the rust repository that tests for some of these and makes sure there consistent between updates. So I wanted to go over each of these and explain how it’s valid rust.