Lua checker on mlua — undefined variable / global / field detection with LuaCats support.

Designed to run before Lua execution, providing a safety net for AI-driven and programmatic Lua code generation.

Backed by emmylua_code_analysis for accurate Lua 5.4 diagnostics.

• Undefined variable — reference to a variable not defined in any enclosing scope
• Undefined global — reference to a global name not in the known symbol table
• Undefined field — access to a field not declared in a ---@class definition
• Unused variable — a local variable that is declared but never referenced
• VM introspection — automatically builds symbol table from live mlua globals

// third argument: optional search paths prepended to Lua's package.path
let result = mlua_check::run_lint("print('hello')", "@main.lua", &[]).unwrap();
assert_eq!(result.diagnostics.len(), 0);

See examples/ for runnable demos (basic_lint, with_vm, luacats). Run any with cargo run --example <name>.

use mlua::prelude::*;
use mlua_check::register;

let lua = Lua::new();

let alc = lua.create_table().unwrap();
alc.set("llm", lua.create_function(|_, ()| Ok(())).unwrap()).unwrap();
lua.globals().set("alc", alc).unwrap();

// register() introspects the VM and builds a symbol table automatically
let engine = register(&lua).unwrap();
let result = engine.lint("alc.llm('hello')", "@main.lua");
assert_eq!(result.diagnostics.len(), 0);

let result = engine.lint("alc.unknown('hello')", "@main.lua");
assert!(result.warning_count > 0);

use mlua_check::{LintConfig, LintPolicy};

let config = LintConfig::default().with_policy(LintPolicy::Strict);

RuleId covers the four common categories (UndefinedVariable, UndefinedGlobal, UndefinedField, UnusedVariable) plus Other(String) for any additional codes reported by the analyser. RuleId is #[non_exhaustive], so match expressions require a wildcard arm.

The following issues from the previous walker-based implementation are resolved:

• for-in loop variables no longer produce false-positive undefined-global diagnostics.
• The Lua 5.4 standard global arg is now recognised without manual declaration.
• Custom globals registered on the mlua VM via register(&lua) are injected into the analyser as a ---@meta virtual stub, eliminating false positives for host-defined names.

Licensed under either of

• MIT license
• Apache License, Version 2.0

at your option.