statix

Lints and suggestions for Nix code. statix check highlights antipatterns, statix fix auto-corrects them. Works on AST level only — no evaluation.

Usage

# scan a directory recursively
statix check /path/to/dir
 
# ignore generated files
statix check . -i Cargo.nix .direnv
 
# disable .gitignore-based filtering
statix check . -u
 
# auto-fix in-place
statix fix /path/to/file
 
# dry run (show diff only)
statix fix --dry-run /path/to/file

Output formats

statix check . -o json    # machine-readable
statix check . -o errfmt  # single-line, vim-friendly

Configuration

Create statix.toml at the project root to disable specific lints:

# statix.toml
disabled = [
  "empty_pattern",
  "unquoted_uri",
]

statix walks up parent directories to find statix.toml, or pass it explicitly with --config.

Generate a base config: statix dump > statix.toml

Lints

Code	Name	Description
W01	bool_comparison	x == true → x
W02	empty_let_in	let in block with no bindings
W03	manual_inherit	x = x; → inherit x;
W04	manual_inherit_from	x = foo.x; → inherit (foo) x;
W05	legacy_let_syntax	old let { } form
W06	collapsible_let_in	nested let in that can be merged
W07	eta_reduction	x: f x → f
W08	useless_parens	unnecessary parentheses
W10	empty_pattern	{ }: with no args used
W11	redundant_pattern_bind	@-bind that is never used
W12	unquoted_uri	bare URI literal (deprecated syntax)
W13	deprecated_is_null	x == null → isNull x (or vice versa)
W14	empty_inherit	inherit; with nothing inherited
W15	faster_groupby	suboptimal groupBy pattern
W16	faster_zipattrswith	suboptimal zipAttrsWith pattern
W17	deprecated_to_path	use of deprecated toPath
W18	bool_simplification	redundant boolean logic
W19	useless_has_attr	? check that is always true/false
W20	repeated_keys	duplicate keys in attrset
W23	empty_list_concat	[] ++ x or x ++ []

Installation

# from nixpkgs
nix run nixpkgs#statix -- help
 
# from source (flake)
nix run git+https://git.peppe.rs/languages/statix -- --help