…ents + CodeRabbit

Four review agents (code-reviewer, pr-test-analyzer, comment-analyzer,
silent-failure-hunter) plus three CodeRabbit comments produced a
batch of cross-cutting findings.  This commit addresses them all
in one pass to avoid the iterative round-trip cost the bug class
itself was filed to eliminate.

**Critical fixes:**

1. **Closure body E615 harvest gap (silent-failure-hunter C1).**
   `_compile_lifted_closure` constructed its own WasmContext but
   never harvested `_interp_inference_failures` — closure bodies
   with E615-triggering interpolation segments were silently
   dropped, producing call_indirect→missing-table-entry WASM
   validation traps with no source-located diagnostic.  Extracted
   the harvest into `CodeGenerator._harvest_interp_inference_failures`
   on the codegen base and called it from both functions.py and
   closures.py.  Removed the now-disproved `# pragma: no cover —
   defensive` claim on closures.py's body-instrs-None path.  New
   regression test `test_e615_in_closure_body_emits_diagnostic`.

2. **`_canonical_named_type` type_args from terminal NamedType
   (CodeRabbit #3 + code-reviewer I1).**  The walker's
   `outer_type_args` capture rule (always read from first NamedType)
   lost type_args when alias_map substitution bound a generic
   param to a parameterised type.  Empirically reachable today via
   `type Mapper<A, B> = fn(A -> B); Mapper<Int, Array<Int>>` etc.
   Fix: drop the "outermost" rule, return type_args from the
   terminal NamedType reached.  All 21 existing #602-class
   regression tests still pass.  New regression test
   `test_canonical_named_type_terminal_args_propagation`.

3. **HISTORY.md footer (CodeRabbit #1).**  141 tagged releases →
   142 to match the v0.0.142 row added in PR #631.

**UX fix:**

4. **Multiple E615 per function (silent-failure-hunter H2).**
   Pre-this-fix `_translate_interpolated_string` returned None on
   the first failing segment, requiring N round-trips for N bad
   segments in one interpolation.  Now collects every failing
   segment via `had_failure` flag, then bails at the end.  New
   regression test `test_multiple_e615_in_one_interpolation`.

**Doc-quality fixes (comment-analyzer):**

5. **Trigger-count drift** in `operators.py:491-494` —
   "every canonicalisation gap (#602 and ten subsequent triggers)"
   implied 11; rewrote to "the ten triggers of the #602 bug class
   accumulated across PRs #627 + #629".

6. **`_format_named_type_canonical` docstring drift** — claim
   "matches the pre-#630 fallback shape" was empirically wrong
   (pre-#630 resolved through aliases, post-#630 fallback doesn't).
   Rewrote to acknowledge the deliberate behavioural change.

7. **"Future closure-arg shapes plug in here without further
   dispatch ladder"** — overstatement.  Adding a `FnCall`
   returning a closure still needs an `elif`; what's saved is
   canonicalisation logic, not dispatch logic.  `IfExpr` between
   closures has no single `return_type` field — example was
   misleading.  Rewrote in both `_infer_fncall_vera_type` and
   `_infer_apply_fn_return_type`.

8. **`_canonical_wasm_type` docstring** — added explicit `Unit →
   None` documentation; clarified that `None` (no WASM type) and
   `"i64"` (unreachable-NamedType default) are distinct return
   shapes that callers must not conflate.

**Tests added (besides the regressions tied to fixes):**

9. **`test_per_function_isolation_of_failures_list`** — pins
   that a clean function and a dirty function in the same source
   produce independent `_interp_inference_failures` lists.

10. **`test_e615_fires_on_result_in_interpolation`** — adjacent
    ADT shape (Result vs Option) so a future Option-handling
    broadening doesn't accidentally regress the parallel Result
    path.

11. **`test_array_map_refinement_returning_closure`** — pins the
    previously-unaudited `_infer_closure_return_vera_type` path
    in `calls_arrays.py`, which the #630 migration broadened to
    handle refinements.

**Test enhancements:**

12. **E615 ordering before matching E602** in the existing test
    (CodeRabbit #2) — pinned via `warnings.index(e615[0])` <
    `warnings.index(matching_e602)`.  Filtered to the E602 that
    mentions the offending function so prelude-skip E602s don't
    confound the assertion.

13. **E615 source-location attached** in the existing test —
    softened to "line > 0" (any location) because SlotRef-inside-
    InterpolatedString spans are unreliable today (#634, separate
    follow-up).  Tightening to "line points at the segment" is
    the natural acceptance test for that follow-up.

**Skipped with reasons:**

- **Cycle-guard regression on `_resolve_base_type_name`** —
  test-analyzer C1 / code-reviewer S4.  Verified pre-existing
  and dead-code-safe today (cycles crash an upstream resolver
  first).  Filed as #633.

- **`_canonical_wasm_type`'s `i64` default for unhandled
  apply_fn / call_indirect shapes** — silent-failure-hunter H1.
  Bigger refactor parallel to Tier 2 but for the WASM-side
  dispatch.  Filed as #632.

- **SlotRef-inside-InterpolatedString span fidelity** —
  surfaced when writing the E615 source-location assertion.
  Diagnostic-quality concern, separate from #630's
  canonicalisation scope.  Filed as #634.

- **`_canonical_named_type` worked-example docstring**
  (comment-analyzer I6) — superseded by fix #2 above (semantics
  changed; docstring rewritten with concrete examples).

- **Per-context isolation prose-vs-test** (comment-analyzer I4)
  — addressed via fix #9 (test added).

- **`_resolve_i32_pair_ret_te` 30-line upper docstring** —
  comment-analyzer style nit.  The prose is load-bearing
  context (#628 cross-module narrative); trimming would lose
  history without obvious gain.  Defer.

**Follow-ups:** #632 (apply_fn / call_indirect E616), #633
(_resolve_base_type_name cycle guard), #634 (interpolation
SlotRef source spans).  Added to KNOWN_ISSUES.md alongside #628.

Counts: 3,792 tests (3,778 passed, 14 skipped) — six new tests
under `TestE615LoudInterpolationFallthrough630`.  CHANGELOG +
KNOWN_ISSUES + ROADMAP + TESTING.md + HISTORY footer all
synced.  mypy clean.

Co-Authored-By: Claude <noreply@anthropic.invalid>

…lone

`test_parameterised_alias_substitutes_type_args` previously only
asserted the presence of `$option_map$Int_Int` after the
`T → Int` substitution.  A regression that emitted BOTH the
substituted clone AND a stray `$option_map$T_T` would still pass
the test silently (partial-substitution bug class).

Added `assert "$option_map$T_T" not in wat` right after the
positive assertion, with an inline comment noting the bug
class it would catch.

Refs #604 #655 #659

Co-Authored-By: Claude <noreply@anthropic.invalid>