Design the salsa db trait and SourceFile input skeleton

jacksonopp commented

2026-08-20 19:06:08 +00:00

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The concrete #[salsa::db] database trait and #[salsa::input] shape for source files, decided before any query logic is written -- this is the part of #1 that's expensive to unwind later if the shape is wrong, since every future query signature (Step 2's checker, Step 9's LSP) depends on it.

Open questions to resolve here:

What does the Db trait look like, and does twill-check own it or does a future LSP crate compose it on top
Is SourceFile a single file or does it need to model a multi-file module graph from the start
Are parse (calling twill-parser) and lower (see the AST-lowering ticket) separate #[salsa::tracked] fns, so downstream queries can depend on lowering without re-running parse on unrelated edits

Follows from the two decisions already made in #1's discussion (real salsa; lower to an owned/interned tree before it crosses a query boundary).

The concrete #[salsa::db] database trait and #[salsa::input] shape for source files, decided before any query logic is written -- this is the part of #1 that's expensive to unwind later if the shape is wrong, since every future query signature (Step 2's checker, Step 9's LSP) depends on it. Open questions to resolve here: - What does the Db trait look like, and does twill-check own it or does a future LSP crate compose it on top - Is SourceFile a single file or does it need to model a multi-file module graph from the start - Are parse (calling twill-parser) and lower (see the AST-lowering ticket) separate #[salsa::tracked] fns, so downstream queries can depend on lowering without re-running parse on unrelated edits Follows from the two decisions already made in #1's discussion (real salsa; lower to an owned/interned tree before it crosses a query boundary).

jacksonopp added this to the Step 2: Core Type Checker milestone

2026-08-20 19:06:08 +00:00

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2026-08-20 19:06:08 +00:00

jacksonopp referenced this issue

2026-08-20 19:06:17 +00:00

Design the checker crate skeleton (crates/twill-check) #1

jacksonopp added this to the twill project

2026-08-20 19:06:38 +00:00

jacksonopp referenced this issue