Crate arkhe_subset_rust_check 

arkhe-subset-rust-check — Subset-Rust Purity Lint (E14.L1-Deny)

AST-level purity check for Action::compute bodies (E14.L1 — Compute Determinism Closure, L1 realisation). Detects determinism- breaking calls — clock / RNG / I/O / FFI — and bans unsafe blocks and unsafe fn signatures inside the scanned function. Returns a list of PurityViolations.

Macro arguments are scanned best-effort: each invocation’s tokens are parsed as a comma-separated expression list and visited; when that parse fails (non-expression DSLs), raw token trees are scanned for ::-joined ident sequences against the same deny rules. Ident sequences directly after . are skipped, mirroring the AST visitor’s method-call exclusion.

Crate shape

Mirrors the arkhe-trait-default-check precedent: a syn-based lib that runs on stable Rust, integrated via the #[arkhe_pure] attribute macro shipped from arkhe-forge-macros. The macro path catches violations at every cargo check. Coverage assertion (“every Action::compute has the attribute”) is delegated to a separate workspace-wide scan in arkhe-trait-default-check.

Spec anchor

• E14 Compute Determinism Closure (MC) — Runtime axiom layer.
• E14.L1-Deny — L1 Action::compute realisation (this crate + #[arkhe_pure]).

Structs

Policy

Purity policy — exact path deny, namespace prefix deny, macro-name deny, and an unsafe ban (blocks + unsafe fn signatures). The default deny_compute_impurity policy covers the 4-rule deny scope (Clock + RNG + I/O + FFI).

PurityViolation

One purity violation — a forbidden call site, prefix-matched namespace access, denied macro invocation, or unsafe block / unsafe fn signature inside the scanned function. Carries the matching deny-list entry plus a span label for diagnostic output.

Functions

check_purity

Scan a function for E14.L1-Deny purity violations under policy.

check_purity_default

Convenience wrapper — scan with the default deny_compute_impurity policy.