sounio-typeck-effects

name	sounio-typeck-effects
description	Work on Sounio type checking and effect system (bidirectional inference, effect inference/enforcement, and type rules); use when editing `compiler/src/typeck/`, `compiler/src/types/`, `compiler/src/check/`, or `compiler/src/effects/`.

Sounio Typeck + Effects

Overview

Make changes to the type system and effect checker without drifting toward Rust or weakening Sounio’s explicit-effects contract.

Workflow

1) Anchor to language identity and current reality

• Read CLAUDE.md for Sounio-native syntax constraints.
• Check compiler/docs/KNOWN_LIMITATIONS.md before implementing surface syntax the compiler doesn’t support yet.
• Treat docs/spec/LANGUAGE_SPECIFICATION.md as aspirational when it disagrees with the compiler.

2) Identify what layer you’re changing

• Parser/AST shape: compiler/src/parser/, compiler/src/ast/
• Type rules / inference: compiler/src/check/, compiler/src/typeck/, compiler/src/types/
• Effects enforcement + inference: compiler/src/effects/ and compiler/src/types/effects.rs

3) Protect effect soundness

• If an operation performs IO/mutation/allocation/etc, ensure the effect set includes it.
• If an operation changes epistemic confidence/provenance, decide whether it must be effectful and enforce it consistently.

4) Add high-signal tests

• Rust integration: compiler/tests/ (e.g. semantic types and effects)
• Diagnostics expectations: tests/ui/
• Language harness: tests/run-pass/, tests/compile-fail/

References

• Typeck map: references/typeck-navigation.md
• Effects map: references/effects-navigation.md
• Claude command reference: .claude/commands/sounio-effects.md