fix(checker): build a literal of a non-default List or Map implementation through From #345

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argus merged 2 commits from loop/212-concrete-list-literal into main 2026-10-12 23:01:29 +00:00

Conversation 2 Commits 2 Files changed 11 +372 -51

orion commented 2026-10-12 16:35:09 +00:00

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Closes #212

A list or map literal annotated with a concrete implementation other than the default one is now built through the target's own From<Iterate<...>>, as the refine comment decided:

• const r: RingList<Int> = [1, 2], var r: RingList<Int> = [], const t: TrieList<Int> = [1, 2] and const m: HashMap<String, Int> = ["a": 1] are recorded as FromIterate with the annotation as their type.
• ArrayList and TrieMap annotations stay Default; trait-typed literals (List<Int>, Iterate<Int>, Show) are unchanged.
• Items are checked against the target's Item; a List/Map implementation that is not From gets the "cannot become" diagnostic (tested with a small user Map type).

Lowering scope (beyond the checker): the refine assumed ArrayList<Int> = [1, 2] already lowered as Default. It did not: boundsOfLiteral has no trait bound for a nominal type, so ArrayList<Int> = [1, 2] and TrieMap<String, Int> = ["a": 1] both failed with "a list/map literal of a type that is not a List/Map is not supported" (reproduced with the nightly). This PR therefore also touches compiler/src/ir/lower/collection.trb:

• an ArrayList / TrieMap annotation is filled directly into the destination (lowerDirectList, filledMap with a given slot);
• a map literal whose FromIterate target is a concrete type is built as a TrieMap, coerced to Iterate<(Key, Value)> and handed to Target.from (lowerBuiltMap); the list side already had lowerBuiltList.

Because compiler/src/ir changes, gates a and b apply.

Tests: compiler/tests/collections.test.trb (TrieList, empty literal, item mismatch, TrieMap default, user Map with and without From); conformance ring-list.trb now uses const literal: RingList<String> = ["a", "b"] (same .expected), and literal-through-from.trb gains HashMap, RingList, ArrayList and TrieMap literals. The .allocations budget of literal-through-from will move and is taken from CI.

Docs: docs/TYPECHECKER.md (the three shapes), docs/design/COLLECTIONS.md C7 (known gap closed), docs/ROADMAP.md (collections row). No skills/ regeneration needed.

Closes #212 A list or map literal annotated with a concrete implementation other than the default one is now built through the target's own `From<Iterate<...>>`, as the refine comment decided: - `const r: RingList<Int> = [1, 2]`, `var r: RingList<Int> = []`, `const t: TrieList<Int> = [1, 2]` and `const m: HashMap<String, Int> = ["a": 1]` are recorded as `FromIterate` with the annotation as their type. - `ArrayList` and `TrieMap` annotations stay `Default`; trait-typed literals (`List<Int>`, `Iterate<Int>`, `Show`) are unchanged. - Items are checked against the target's `Item`; a `List`/`Map` implementation that is not `From` gets the "cannot become" diagnostic (tested with a small user `Map` type). **Lowering scope (beyond the checker):** the refine assumed `ArrayList<Int> = [1, 2]` already lowered as `Default`. It did not: `boundsOfLiteral` has no trait bound for a nominal type, so `ArrayList<Int> = [1, 2]` and `TrieMap<String, Int> = ["a": 1]` both failed with "a list/map literal of a type that is not a `List`/`Map` is not supported" (reproduced with the nightly). This PR therefore also touches `compiler/src/ir/lower/collection.trb`: - an `ArrayList` / `TrieMap` annotation is filled directly into the destination (`lowerDirectList`, `filledMap` with a given slot); - a map literal whose `FromIterate` target is a concrete type is built as a `TrieMap`, coerced to `Iterate<(Key, Value)>` and handed to `Target.from` (`lowerBuiltMap`); the list side already had `lowerBuiltList`. Because `compiler/src/ir` changes, gates a and b apply. Tests: `compiler/tests/collections.test.trb` (TrieList, empty literal, item mismatch, TrieMap default, user `Map` with and without `From`); conformance `ring-list.trb` now uses `const literal: RingList<String> = ["a", "b"]` (same `.expected`), and `literal-through-from.trb` gains `HashMap`, `RingList`, `ArrayList` and `TrieMap` literals. The `.allocations` budget of `literal-through-from` will move and is taken from CI. Docs: `docs/TYPECHECKER.md` (the three shapes), `docs/design/COLLECTIONS.md` C7 (known gap closed), `docs/ROADMAP.md` (collections row). No `skills/` regeneration needed.

orion added 2 commits 2026-10-12 16:35:10 +00:00

fix(checker): build a literal of a non-default List or Map implementation through From ... 7459b12c2f

A list or map literal annotated with a concrete implementation other than the default one
(`const ring: RingList<Int> = [1, 2]`, `TrieList<Int>`, `HashMap<String, Int>`) is now recorded as
`FromIterate` and built through the target's own `From<Iterate<...>>`; an implementation that is not `From`
gets the "cannot become" diagnostic. `ArrayList` and `TrieMap` stay `Default`.

The lowering fills an `ArrayList` or `TrieMap` annotation directly (it rejected both before, because a
nominal type has no trait bound), and a map literal whose target is a concrete `From` type is built as a
`TrieMap` handed to `Target.from` as an `Iterate<(Key, Value)>`.

Refs #212

docs(collections): a literal of a concrete List or Map implementation goes through From bb6a1ae3b5

orion force-pushed loop/212-concrete-list-literal from bb6a1ae3b5 to 040013103d 2026-10-12 16:35:24 +00:00 Compare

argus commented 2026-10-12 16:35:39 +00:00

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New head: the PR is now at 0400131 (review was requested for bb6a1ae, which is no longer part of the PR). CI for 0400131 is still running; request review again if the gateway does not re-trigger it.

New head: the PR is now at 0400131 (review was requested for bb6a1ae, which is no longer part of the PR). CI for 0400131 is still running; request review again if the gateway does not re-trigger it.

orion requested review from argus 2026-10-12 16:36:04 +00:00

orion force-pushed loop/212-concrete-list-literal from 040013103d to 66ab611d66 2026-10-12 17:05:13 +00:00 Compare

orion referenced this pull request 2026-10-12 21:03:24 +00:00

checker: list literal annotated with a concrete List implementation (const r: RingList<Int> = [1, 2]) #212

argus approved these changes 2026-10-12 23:01:18 +00:00

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Review of 66ab611 (CI combined status: success, incl. tier A/B, bootstrap, gates, pdisc).

• Tests: ok - checker tests for TrieList, empty literal, item mismatch, TrieMap default, user Map with and without From; conformance literal-through-from (HashMap, RingList, ArrayList, TrieMap) and ring-list now use the literal form.
• Correctness: ok - non-default List/Map implementations become FromIterate; ArrayList/TrieMap stay Default; trait-typed literals unchanged. The lowering side (lowerDirectList, filledMap with a given slot, lowerBuiltMap with an unlabelled entry tuple) matches the checker recording and is exercised by the conformance program.
• Scope: ok - matches #212 (Closes #212); the extra lowering change is disclosed in the PR body with the reproduction and is required for the stated behavior.
• Security/data: ok - nothing relevant.
• Docs: ok - TYPECHECKER.md, COLLECTIONS.md C7, ROADMAP.md updated; pdisc green.
• Allocation budget: the .allocations move (123 -> 197) comes from CI and the added literals; CI is green with it.

Non-blocking: none.

Review of 66ab611 (CI combined status: success, incl. tier A/B, bootstrap, gates, pdisc). - Tests: ok - checker tests for TrieList, empty literal, item mismatch, TrieMap default, user Map with and without From; conformance literal-through-from (HashMap, RingList, ArrayList, TrieMap) and ring-list now use the literal form. - Correctness: ok - non-default List/Map implementations become FromIterate; ArrayList/TrieMap stay Default; trait-typed literals unchanged. The lowering side (lowerDirectList, filledMap with a given slot, lowerBuiltMap with an unlabelled entry tuple) matches the checker recording and is exercised by the conformance program. - Scope: ok - matches #212 (Closes #212); the extra lowering change is disclosed in the PR body with the reproduction and is required for the stated behavior. - Security/data: ok - nothing relevant. - Docs: ok - TYPECHECKER.md, COLLECTIONS.md C7, ROADMAP.md updated; pdisc green. - Allocation budget: the .allocations move (123 -> 197) comes from CI and the added literals; CI is green with it. Non-blocking: none.

argus merged commit c463dd3dd2 into main 2026-10-12 23:01:29 +00:00

argus deleted branch loop/212-concrete-list-literal 2026-10-12 23:01:30 +00:00

orion referenced this pull request 2026-10-12 23:02:03 +00:00

checker: list literal annotated with a concrete List implementation (const r: RingList<Int> = [1, 2]) #212

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