constcheck

Overview ¶

Package constcheck enforces Lua 5.4's local attributes at compile time: a local declared `<const>` or `<close>` may never be assigned after its declaration. The pass runs unconditionally in the compile pipeline (unlike the type checker it is not gated by `--!nocheck`), matching PUC Lua where assigning to a const local is a syntax-level error.

Only the *assignment* rule is enforced here. The `<close>` attribute's runtime behaviour (calling `__close` at scope exit) is a documented language-level non-goal for now; `<close>` locals get the same no-reassignment protection as `<const>` and are otherwise inert.