Implement name-based type checker

.claude/skills/type-checker-tests/SKILL.md → .agents/skills/type-checker-tests/SKILL.md

@@ -48,6 +48,15 @@ test' [x] = x
 just t checking NNN MMM
 ```
 
+### 4. Accept or reject snapshots
+
+```bash
+just t checking NNN --diff        # Inspect a fixture diff
+just t checking NNN --accept      # Accept a specific fixture
+just t checking NNN --reject      # Reject a specific fixture
+just t checking --accept --confirm # Accept all pending snapshots
+```
+
 ## Multi-File Tests
 
 For imports, re-exports, or cross-module behavior:

.claude/skills/type-checker-tests/reference/compiler-scripts.md → .agents/skills/type-checker-tests/reference/compiler-scripts.md

@@ -28,11 +28,12 @@ just t <category> --delete "name"  # Dry-run fixture deletion (use --confirm)
 ### Snapshot commands
 
 ```bash
-just t <category> accept [--all] [filters...]  # Accept pending snapshots
-just t <category> reject [--all] [filters...]  # Reject pending snapshots
+just t <category> [filters...] --accept             # Accept matching snapshots
+just t <category> [filters...] --reject             # Reject matching snapshots
+just t <category> --accept --confirm                # Accept all pending snapshots
 ```
 
-Requires `--all` flag when no filters provided (safety guardrail).
+For safety, unfiltered `--accept` requires `--confirm`.
 
 ### Exclusion filters
 

.claude/skills

@@ -0,0 +1 @@
+../.agents/skills

compiler-compatibility/command/src/compat.rs

@@ -11,9 +11,8 @@ use petgraph::graphmap::DiGraphMap;
 use rayon::prelude::*;
 use url::Url;
 
-use crate::loader;
-use crate::resolver;
 use crate::types::ResolvedSet;
+use crate::{loader, resolver};
 
 /// Result of checking a single file.
 pub struct FileResult {
@@ -415,10 +414,11 @@ fn find_package_dir(packages_dir: &Path, package_name: &str) -> Option<std::path
     for entry in entries.filter_map(Result::ok) {
         let name = entry.file_name();
         let name_str = name.to_string_lossy();
-        if let Some(suffix) = name_str.strip_prefix(&prefix) {
-            if suffix.parse::<semver::Version>().is_ok() && entry.file_type().ok()?.is_dir() {
-                return entry.path().canonicalize().ok();
-            }
+        if let Some(suffix) = name_str.strip_prefix(&prefix)
+            && suffix.parse::<semver::Version>().is_ok()
+            && entry.file_type().ok()?.is_dir()
+        {
+            return entry.path().canonicalize().ok();
         }
     }
     None

compiler-core/building-types/src/lib.rs

@@ -19,6 +19,7 @@ pub enum QueryKey {
     Bracketed(FileId),
     Sectioned(FileId),
     Checked(FileId),
+    Checked2(FileId),
 }
 
 #[derive(Error, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]

compiler-core/building/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2024"
 [dependencies]
 building-types = { version = "0.1.0", path = "../building-types" }
 checking = { version = "0.1.0", path = "../checking" }
+checking2 = { version = "0.1.0", path = "../checking2" }
 files = { version = "0.1.0", path = "../files" }
 indexing = { version = "0.1.0", path = "../indexing" }
 interner = { version = "0.1.0", path = "../interner" }
@@ -19,6 +20,7 @@ resolving = { version = "0.1.0", path = "../resolving" }
 rustc-hash = "2.1.1"
 stabilizing = { version = "0.1.0", path = "../stabilizing" }
 sugar = { version = "0.1.0", path = "../sugar" }
+smol_str = "0.3.2"
 tempfile = "3.24.0"
 thread_local = "1.1.9"
 url = "2.5.7"

compiler-core/building/src/engine.rs

@@ -34,6 +34,7 @@ use building_types::{
     ModuleNameId, ModuleNameInterner, QueryError, QueryKey, QueryProxy, QueryResult,
 };
 use checking::{CheckedModule, TypeInterner};
+use checking2::CheckedModule as CheckedModule2;
 use files::FileId;
 use graph::SnapshotGraph;
 use indexing::IndexedModule;
@@ -99,12 +100,14 @@ struct DerivedStorage {
     bracketed: FxHashMap<FileId, DerivedState<Arc<sugar::Bracketed>>>,
     sectioned: FxHashMap<FileId, DerivedState<Arc<sugar::Sectioned>>>,
     checked: FxHashMap<FileId, DerivedState<Arc<CheckedModule>>>,
+    checked2: FxHashMap<FileId, DerivedState<Arc<CheckedModule2>>>,
 }
 
 #[derive(Default)]
 struct InternedStorage {
     module: ModuleNameInterner,
     types: TypeInterner,
+    checking2: checking2::CoreInterners,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -428,6 +431,7 @@ impl QueryEngine {
                 QueryKey::Bracketed(k) => derived_changed!(bracketed, k),
                 QueryKey::Sectioned(k) => derived_changed!(sectioned, k),
                 QueryKey::Checked(k) => derived_changed!(checked, k),
+                QueryKey::Checked2(k) => derived_changed!(checked2, k),
             }
         }
 
@@ -757,6 +761,18 @@ impl QueryEngine {
             },
         )
     }
+
+    pub fn checked2(&self, id: FileId) -> QueryResult<Arc<CheckedModule2>> {
+        self.query(
+            QueryKey::Checked2(id),
+            |storage| storage.derived.checked2.get(&id),
+            |storage| storage.derived.checked2.entry(id),
+            |this| {
+                let checked = checking2::check_module(this, id)?;
+                Ok(Arc::new(checked))
+            },
+        )
+    }
 }
 
 impl QueryEngine {
@@ -841,6 +857,68 @@ impl checking::ExternalQueries for QueryEngine {
     }
 }
 
+impl checking2::ExternalQueries for QueryEngine {
+    fn checked2(&self, id: FileId) -> QueryResult<Arc<checking2::CheckedModule>> {
+        QueryEngine::checked2(self, id)
+    }
+
+    fn intern_type(&self, t: checking2::core::Type) -> checking2::core::TypeId {
+        let mut storage = self.storage.write();
+        storage.interned.checking2.intern_type(t)
+    }
+
+    fn lookup_type(&self, id: checking2::core::TypeId) -> checking2::core::Type {
+        let storage = self.storage.read();
+        storage.interned.checking2.lookup_type(id)
+    }
+
+    fn intern_forall_binder(
+        &self,
+        binder: checking2::core::ForallBinder,
+    ) -> checking2::core::ForallBinderId {
+        let mut storage = self.storage.write();
+        storage.interned.checking2.intern_forall_binder(binder)
+    }
+
+    fn lookup_forall_binder(
+        &self,
+        id: checking2::core::ForallBinderId,
+    ) -> checking2::core::ForallBinder {
+        let storage = self.storage.read();
+        storage.interned.checking2.lookup_forall_binder(id)
+    }
+
+    fn intern_row_type(&self, row: checking2::core::RowType) -> checking2::core::RowTypeId {
+        let mut storage = self.storage.write();
+        storage.interned.checking2.intern_row_type(row)
+    }
+
+    fn lookup_row_type(&self, id: checking2::core::RowTypeId) -> checking2::core::RowType {
+        let storage = self.storage.read();
+        storage.interned.checking2.lookup_row_type(id)
+    }
+
+    fn intern_synonym(&self, synonym: checking2::core::Synonym) -> checking2::core::SynonymId {
+        let mut storage = self.storage.write();
+        storage.interned.checking2.intern_synonym(synonym)
+    }
+
+    fn lookup_synonym(&self, id: checking2::core::SynonymId) -> checking2::core::Synonym {
+        let storage = self.storage.read();
+        storage.interned.checking2.lookup_synonym(id)
+    }
+
+    fn intern_smol_str(&self, s: smol_str::SmolStr) -> checking2::core::SmolStrId {
+        let mut storage = self.storage.write();
+        storage.interned.checking2.intern_smol_str(s)
+    }
+
+    fn lookup_smol_str(&self, id: checking2::core::SmolStrId) -> smol_str::SmolStr {
+        let storage = self.storage.read();
+        storage.interned.checking2.lookup_smol_str(id)
+    }
+}
+
 impl resolving::ExternalQueries for QueryEngine {}
 
 impl sugar::ExternalQueries for QueryEngine {}

compiler-core/checking/src/algorithm/constraint/compiler_solved/prim_row.rs

@@ -4,12 +4,11 @@ use std::iter;
 use building_types::QueryResult;
 use rustc_hash::FxHashSet;
 
-use crate::ExternalQueries;
 use crate::algorithm::constraint::{self, MatchInstance};
 use crate::algorithm::state::{CheckContext, CheckState};
 use crate::algorithm::toolkit;
 use crate::core::{RowField, RowType};
-use crate::{Type, TypeId};
+use crate::{ExternalQueries, Type, TypeId};
 
 use super::extract_symbol;
 
@@ -127,7 +126,10 @@ where
                 .storage
                 .intern(Type::Row(RowType::from_unsorted(union_fields, right_row.tail)));
 
-            Ok(Some(MatchInstance::Match { constraints: vec![], equalities: vec![(union, result)] }))
+            Ok(Some(MatchInstance::Match {
+                constraints: vec![],
+                equalities: vec![(union, result)],
+            }))
         }
         (_, Some(right_row), Some(union_row)) => {
             if right_row.tail.is_some() {

compiler-core/checking2/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "checking2"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+building-types = { version = "0.1.0", path = "../building-types" }
+files = { version = "0.1.0", path = "../files" }
+indexing = { version = "0.1.0", path = "../indexing" }
+interner = { version = "0.1.0", path = "../interner" }
+itertools = "0.14.0"
+lowering = { version = "0.1.0", path = "../lowering" }
+petgraph = "0.8.3"
+pretty = "0.12"
+parsing = { version = "0.1.0", path = "../parsing" }
+resolving = { version = "0.1.0", path = "../resolving" }
+rustc-hash = "2.1.1"
+smol_str = "0.3.5"
+stabilizing = { version = "0.1.0", path = "../stabilizing" }
+sugar = { version = "0.1.0", path = "../sugar" }