iter 23.4-prep: per-iter journal

docs/journals/2026-05-11-iter-23.4-prep.md

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+# iter 23.4-prep — checker prerequisites for prelude free fns
+
+**Date:** 2026-05-11
+**Branch:** iter/23.4-prep
+**Status:** DONE
+**Tasks completed:** 2 of 2
+
+## Summary
+
+Closes two localised checker gaps that BLOCKED iter 23.4 mid-flight:
+
+- **Gap 2 (Task 1):** `linearity::check_module`'s globals-construction
+  loop now iterates `Def::Class` methods and registers each method
+  type in the globals map. Previously, a borrow-mode fn that
+  forwarded its borrow-mode params into a class-method call fired
+  `consume-while-borrowed` false positives, because
+  `callee_arg_modes` defaulted to `Consume` when it could not find
+  the method's `param_modes`. `Def::Instance` stays a no-op:
+  instance method bodies are walked separately via `Def::Fn` after
+  monomorphisation, per the comment in the new arm.
+
+- **Gap 1 (Task 2):** the `Term::Var { name }` lookup ladder in
+  `synth` grows one new branch between the class-method arm and the
+  dot-qualified arm. It iterates `env.imports.values()` to find a
+  free-fn match in any implicitly-imported module's flat-globals
+  table; on hit, it qualifies any owner-module-local Type::Cons via
+  the existing `qualify_local_types` helper (mirror of the
+  dot-qualified arm). Today the prelude is the only implicit
+  import, so single-match-wins is unambiguous; the code comment
+  names the future revisit point for multi-implicit-import
+  ambiguity.
+
+Both fixes are intra-crate and additive — no schema change, no new
+diagnostic, no new workspace plumbing. iter 23.4's five prelude
+free fns (`ne`/`lt`/`le`/`gt`/`ge`) can now ship against the
+existing plan unchanged.
+
+## Per-task subjects
+
+- iter 23.4-prep.1: linearity — register Def::Class method types in globals
+- iter 23.4-prep.2: check — bare-name fall-through to implicit-imported free fns
+
+## Concerns
+
+- No E2E fixture added under `examples/`. The plan's own "Plan
+  self-review" identifies the two RED-first tests (one in
+  `linearity.rs`, one in `lib.rs`'s `check_workspace`-level test
+  module) as the iter-23.4-prep-shaped coverage. The natural E2E
+  surface (a fixture calling bare `ne 1 2` against the prelude)
+  cannot land until iter 23.4 ships the prelude free fns
+  themselves — both `examples/prelude.ail.json` and the consumer
+  fixture are out of scope for this iter. iter 23.4's E2E coverage
+  is the right place; flagging here so the next iter does not
+  inherit "no E2E for the prep iter" as unrecorded debt.
+
+## Known debt
+
+- The Task 2 branch's `mod_name` first-match-wins rule remains
+  ambiguous-by-design as long as `prelude` is the singleton
+  implicit import. If a second implicit import lands in a future
+  milestone, this branch needs a duplicate-detection diagnostic
+  ("name `X` resolves through implicit imports `A` and `B`,
+  qualify the call"). The code comment names the revisit point.
+
+## Blocked detail
+
+N/A — DONE.
+
+## Commits
+
+c10acf0a..aef4ab84
+
+## Stats
+
+bench/orchestrator-stats/2026-05-11-iter-23.4-prep.json