style_lint: add STYLE031 (table insert run → table literal), revive dead STYLE021

[borisbat]

STYLE031 — table insert run → table literal

The table twin of STYLE012: an empty table<K;V> (or table<K> set) declaration followed by ≥ 2 contiguous t |> insert(k, v) / t[k] = v statements collapses to a table (set) literal move-assign:

// Bad
var t : table<string; int>
t |> insert("a", 1)
t["b"] = 2

// Good
var t <- { "a" => 1, "b" => 2 }

Semantics probed before writing the rule:

• Computed keys are allowed — a runtime-duplicate key in a literal is last-wins, identical to sequential inserts.
• Runs with a duplicate CONST key stay silent — sequential inserts overwrite, but a literal rejects duplicate constant keys at compile time (error[30706]), so the rewrite would not compile. Type-tagged const-key comparison covers string/int/uint/int64/uint64/float/double/bool/enum keys.
• insert rejects non-copyable values (error[31400]), so every run the lint can see is literal-compatible — no emplace special-casing needed.
• Mixed runs (insert + []=) and exact-arity matching (3-arg map, 2-arg set; the positional array overloads can't leak in).

STYLE021 was dead code — revived

Wiring the STYLE031↔STYLE021 handoff (JV tables with const keys should keep the stronger JV((k1=..., k2=...)) suggestion) exposed that STYLE021 never fired since landing: its type check matched a tHandle annotation named "JsonValue", but JsonValue is a das struct (daslib/json.das). It also had no test. Fixed the match (tPointer → tStructure, name + module json) and added the missing style021_jv_table_insert.das test pinning both the rule and the handoff. Computed-key JV runs now fall through to STYLE031.

Tree sweep (19 hits)

• 6 fixtures rewritten to literals — linq table-source fixture (now a direct return <- { ... }), long_length, with_boost ×2, serialization + data_walker tutorials.
• 12 nolint'd with reasons — sites where insert/[]= is the machinery under test: fused tab[k]=v opcodes, packed-table WithHash nodes, dapi layout, value-key table API, and the two tutorials that deliberately teach the insert API. (The fused-overwrite test has duplicate const keys and was already correctly skipped by the dup guard.)
• Touched files also cleaned of pre-existing STYLE001/STYLE028/LINT003/LINT013 warnings (incl. 16× self->pad( in the data-walker tutorial).

Docs

• lint.rst: STYLE031 section + STYLE021 fall-through note
• skills/style_lint.md: rows for 031 and the previously missing 029/030; STYLE021 row corrected
• CLAUDE.md: idiom-table row; module docstring gained the missing STYLE023 line

Validation

Preflight full tier: 16 passed, 0 failed (cpp-syntax skipped — no C++ changes), including sphinx-latex/html + pdflatex, tests-interp/jit/aot, and sequence smoke. 43/43 lint-rule tests, 190/190 runtime tests in touched dirs, tree re-sweep zero remaining hits, detect-dupe clean on the new functions.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds a new style-lint rule (STYLE031) to collapse “empty table + contiguous insert/[]= run” into a table/set literal move-assign, and fixes STYLE021 so it correctly detects table<string; JsonValue?> insert-runs and hands off to STYLE031 for computed-key cases. The PR also updates docs, adds targeted lint-rule tests, and refreshes several tutorials/tests to either use literals or explicitly suppress the new lint where incremental insertion is the point.

Changes:

• Implement STYLE031 in daslib/style_lint.das, including duplicate-const-key suppression and STYLE021 handoff.
• Revive STYLE021 by correcting its JsonValue type match and adding regression tests for STYLE021/STYLE031 division of labor.
• Sweep affected fixtures/tutorials/tests: rewrite eligible insert-runs to literals and add nolint annotations where insert/[]= behavior is under test or being taught; update docs/skills tables accordingly.

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
utils/lint/tests/style031_table_insert_run.das	New rule test coverage for STYLE031 across map/set/[]=/mixed/computed-key and JV-handoff scenarios.
utils/lint/tests/style021_jv_table_insert.das	New regression test ensuring STYLE021 fires for const-key JV table runs and computed-key runs fall through to STYLE031.
tutorials/language/47_data_walker.das	Removes self-> noise (STYLE028) and replaces a simple table build with a literal.
tutorials/language/41_serialization.das	Rewrites table initialization sequence into a table literal.
tutorials/language/30_json.das	Adds nolint:STYLE021 to keep incremental-building tutorial example intact.
tutorials/language/10_tables.das	Adds nolint:STYLE031 to preserve insert-API teaching example.
tests/with_boost/test_with_table.das	Rewrites contiguous insert-run into a literal to satisfy STYLE031.
tests/with_boost/test_with_lock_panics.das	Renames unused with_ binders and rewrites one insert-run into a literal.
tests/table_packed/test_packed.das	Adds nolint:STYLE031 where packed-table insert path is the subject under test.
tests/table_packed/test_packed_constkey.das	Adds nolint:STYLE031 in const-key insert/[]=-path tests.
tests/long_array_table/test_long_length.das	Rewrites a simple table build into a literal.
tests/long_array_table/test_fusion_table_i64.das	Adds nolint:STYLE031 where fused tab[k]=v write path is under test.
tests/long_array_table/test_dapi_layout.das	Adds nolint:STYLE031 where canonical insert layout behavior is under test.
tests/linq/test_linq_table_source.das	Rewrites table factory function to return a table literal.
tests/language/test_value_table_key.das	Adds nolint:STYLE031 and updates table get callback callsites to the modern $(...) form.
skills/style_lint.md	Documents STYLE031, updates STYLE021 description (including the handoff behavior), and adds missing STYLE029/STYLE030 rows.
doc/source/reference/language/lint.rst	Documents STYLE031 and clarifies STYLE021 computed-key fall-through to STYLE031.
daslib/style_lint.das	Core implementation: revive STYLE021 type match and add new STYLE031 detection and messaging.
CLAUDE.md	Adds STYLE031 to the style-lint idiom migration table.

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