Writing a Custom Lint

The authoritative, up-to-date guide for adding a new lint to soroban-cost-linter is DEVELOPING_LINTS.md at the repository root (also at DEVELOPING_LINTS.md on GitHub).

Follow that guide. It contains everything you need: where lint declarations and registration live (soroban_cost_lints/src/lib.rs, with the three coordinated registration edits), where UI fixtures go (soroban_cost_lints/ui/), how to use clippy_utils, an end-to-end walkthrough of a real lint, and the exact commands CI enforces.

The older content on this page is intentionally removed because it described a soroban_cost_lints/src/lints/ directory, a tests/ui/ fixture directory, and a `cargo test --test ui_<name> target that do not exist in this repository — none of it would work.