6.4. lint — Paranoid, Performance, and Style

The lint utility runs daslang’s three lint passes — paranoid (daslib/lint), performance (daslib/perf_lint), and style (daslib/style_lint) — over one or more files and reports every issue. It is the same machinery the MCP lint tool drives and the same machinery a future CI gate will use to enforce a warning-free daslib/.

6.4.1. Quick start

Lint a single file:

daslang utils/lint/main.das -- path/to/script.das

Lint a directory tree (every reachable .das file):

daslang utils/lint/main.das -- path/to/dir

Lint the whole stdlib:

daslang utils/lint/main.das -- daslib

The runner skips files that declare expect <code>:<count> directives (used by dastest to assert intentional compile errors) since the lint passes need a successfully-compiled AST. Their rule coverage comes from dedicated tests under utils/lint/tests/.

6.4.2. Flags

  • -q / --quiet — suppress per-file PASS lines and progress messages; only WARN and the summary are printed.

  • --comment-hygiene — enable the opt-in comment-length checks STYLE014 (multi-line // / //! blocks at module/public scope) and STYLE015 (multi-line comments inside def private). Off by default.

  • --paranoid-only — run only the paranoid pass.

  • --perf-only — run only the performance pass.

  • --style-only — run only the style pass.

  • -? / --help — show usage and exit.

6.4.3. Compile policies

The runner compiles each file with a CodeOfPolicies tuned for lint:

  • lint_check = true — marks the program as lint-only, skipping some passes that would normally enforce production-only invariants.

  • no_optimizations = true — disables the optimizer.

  • no_infer_time_folding = true — disables infer-time constant folding.

These flags matter for rules that inspect the source-level shape of an expression. PERF019 (int(T.a) | int(T.b) cast collapse), STYLE022 (bitfield |= BfT.m → field assignment), and STYLE023 (bitfield int_cast(bf & BfT.m) != 0 → bf.m) all depend on the un-folded AST being available; without these policies the optimizer collapses the very patterns they look for.

6.4.4. Rule list

The full rule catalogue lives in Lint Tools. Each rule has its own section there with bad/good examples and detection notes.

6.4.5. Suppression

Add // nolint:RULExxx to the line that fires the warning:

let ch = character_at(s, idx) // nolint:PERF003 — single indexed access

The suppression is exact: // nolint:PERF003 only suppresses PERF003. Stack multiple rules on the same line if needed: // nolint:PERF003,STYLE001.

6.4.6. Planned CI gate

Once daslib/ and the bundled modules under modules/ are warning-free, a CI workflow will gate every PR on:

daslang utils/lint/main.das -- daslib modules/dasSQLITE/daslib

Existing rule exceptions are recorded via // nolint: annotations in the source itself; the gate will not maintain an external allow-list.