refactor(elaborator): identify every declaration by DefId

docs/compiler.md

@@ -11,7 +11,8 @@ The Wado compiler (`wado-compiler/`) translates `.wado` source into a Wasm compo
 ```
 Source (.wado)
   → Lex → Parse → Bind                    (per module, in loader)
-  → Annotate (Analyze + Resolve + lower TIR)
+  → Analyze → Resolve
+  → Annotate (decls, then bodies) → Liveness → Reify (TIR)
   → Default-purity Check
   → Synthesis (auto-derives, template, From, serde, pre-CM effect dispatch, CM bindings)
   → Effect Check → Stores Check
@@ -31,7 +32,11 @@ The driver is `compile_after_load` in `src/lib.rs`.
 | Lex / Parse            | AST             | `lexer.rs`, `parser.rs`, `token.rs`, `syntax.rs` |
 | Bind                   | AST + bindings  | `bind.rs`                                        |
 | Loader                 | All modules     | `loader.rs`                                      |
-| Annotate               | TIR + facts     | `semantics.rs`, `analyze.rs`, `elaborator/`      |
+| Analyze                | `SymbolTable`   | `analyze.rs`                                     |
+| Resolve                | Declarations    | `defs.rs`, `resolve.rs`                          |
+| Annotate               | `Semantics`     | `semantics.rs`, `elaborator/`                    |
+| Liveness               | Reachability    | `elaborator/liveness.rs`                         |
+| Reify                  | `TirModule`     | `elaborator/reify.rs`                            |
 | Default-purity Check   | (validation)    | `effect_check.rs::check_default_purity`          |
 | Synthesis              | TIR (extended)  | `synthesis/`                                     |
 | Effect / Stores        | TIR (validated) | `effect_check.rs`                                |
@@ -51,7 +56,7 @@ The driver is `compile_after_load` in `src/lib.rs`.
 | Unit                              | Layer                                                                                                        |
 | --------------------------------- | ------------------------------------------------------------------------------------------------------------ |
 | `Module` (`ast.rs`)               | Surface AST. Preserves source-level syntax to support `wado format`.                                         |
-| `TirModule` (`tir.rs`)            | Typed IR. One per source module after annotate.                                                              |
+| `TirModule` (`tir.rs`)            | Typed IR. One per source module, emitted by reify.                                                           |
 | `Package` (`package.rs`)          | Per-module compilation context, used from synthesis through link.                                            |
 | `FlatPackage` (`flat_package.rs`) | Flat list of all functions, types, and globals; used from monomorphize through the lower pipeline's planner. |
 | `NirPackage` (`nir_package.rs`)   | Normalized IR. Output of lower, input to optimize / WIR build / codegen.                                     |
@@ -69,9 +74,16 @@ The loader runs `lexer → parser → bind` on every loaded module:
 
 The AST is parser-immutable from this point on. The desugar-replacement surface rewrites — compound assignment (`x += y` → `x = x + y`), `while` / C-style `for` → explicit `loop`, `for x of expr` iteration (the `.into_iter()` / `.next()` dispatch and the `match Some(x) => body, _ => break` shape), the `assert` statement, the `matches` operator, the comparison chain `a < b < c`, template-string interpolations, `use … namespace` prefix stripping (`helper::foo`), and `Self::method` / `T::method` (T bound to concrete) static-call dispatch — happen inside the elaborator and are built TIR-direct: each rewrite resolves the user AST and constructs `TirExpr` / `TirStmt` nodes directly without producing synthetic AST. The implementations live in `elaborator/{stmt,operators,assert,matches}.rs` (`resolve_while`, `resolve_for`, `resolve_iterator_for_of`, `resolve_compound_assign`, `desugar_assert`, `desugar_matches_expr`, `desugar_comparison_chain`), `Elaborator::strip_ns_prefix` in `elaborator.rs`, and `CalleeIdentKind` / `classify_call_callee` in `elaborator/call.rs` (the prefix is resolved to its concrete type name before parameter-type lookup so argument resolution runs once with the correct expected-type hints). Synthetic call sites that need to dispatch a method on an already-resolved receiver TIR (the for-of `.into_iter()` / `.next()` calls today) reuse the AST-driven method dispatch via `Elaborator::resolve_method_call_with` (`elaborator/method_call.rs`) — that helper takes a pre-resolved receiver plus a method name and signals "no source AST" with `method_id: None` so no use→def edge is recorded against the synthesis site. Keeping the AST parser-shaped is what lets LSP queries land on the user's text rather than on a synthesised replacement.
 
-## Annotate (Analyze + Resolve + TIR Lowering)
+## Analyze and Elaborate
 
-`semantics_of` (`semantics.rs`) is the entry point shared by LSP and batch compilation. It runs `analyze.rs` for symbol-table construction and `elaborator/` for type checking; bodies are then lowered into TIR.
+`semantics_of` (`semantics.rs`) is the entry point shared by LSP and batch compilation. It runs `analyze.rs` for the symbol table, then `elaborator/` for the phases below ([WEP 2026-05-26](./wep-2026-05-26-elaborator-rearchitecture.md)):
+
+- **Resolve** answers every reference site once, from the module that wrote it, and identifies every declaration (`defs.rs`, `resolve.rs`, [WEP 2026-08-12](./wep-2026-08-12-declaration-identity.md)). A reference site is answered nowhere else; the positions no site answers derive their `DefId` from a module the caller names.
+- **Annotate** runs a declaration pass over every module — types, `TraitEnv`, `Signatures` — then a body walk whose sole output is a populated `ModuleSemantics`.
+- **Liveness** computes source-level reachability, which gates what reify emits and feeds the unused diagnostics.
+- **Reify** reads the recorded facts back and emits one `TirModule` per module. No inference, no dispatch decisions.
+
+The LSP path stops after liveness and builds no TIR.
 
 The result, `Semantics`, carries the TIR modules plus an `AstIndex` and a use→def map (`AstId → AstId`, globally-unique ids). This is what makes the architecture LSP-friendly: facts are attached to AST nodes without mutating them, so cross-file navigation, hover, and rename all fall out of the same data the batch compiler uses. See the [LSP](#lsp) section below.
 

docs/wep-2026-05-26-elaborator-rearchitecture.md

@@ -518,7 +518,7 @@ and the surviving suppression is the argument-classification probe.
       logger, interner, invocations, entry module) behind one `ElabEnv` field,
       dissolve `AnnotateState` — `tysys` and `module_semantics` land on
       `Semantics`, the rest are driver locals — and collapse the per-module
-      construction site. Takes `Elaborator` from 11 fields to 7.
+      construction site.
 
 ## Consequences
 

docs/wep-2026-07-09-local-item-definitions.md

@@ -94,6 +94,30 @@ whether reify or this WEP's eager annotate-time emission produced it.
   generic `type` surfaces as a type mismatch, since it needs a different
   mechanism — `GenericNewtypeInfo` + AST substitution, not the monomorphized
   template generic structs use — that this WEP does not wire up. Methods on
-  any local type surface as `no method 'x' found on type`, since a local
-  `impl`/`trait` block parses but is not connected to method dispatch, a
-  module-wide registry built once before any function body is walked.
+  any local type surface as `no method 'x' found on type`.
+
+## Known gap: methods on a local type
+
+Two module-wide registries are built before any function body is walked, and a
+local `impl` needs both.
+
+- `TraitEnv` indexes `module.items`, so no local block reaches it. A body walk
+  can be added: the target's head has its own reference site, and a block whose
+  target is a function-local declaration is scoped by that identity, since two
+  sibling blocks' same-named types are two declarations.
+- `Signatures` is assembled between the declaration pass and the body walk and
+  is read-only after. A local `impl`'s target is a block-local type whose
+  `TypeId` is interned _during_ that walk, so its method signatures cannot
+  exist before the freeze.
+
+Closing it means either giving a local type declaration its durable identity
+and `TypeId` in the declaration pass — `declare_local_struct` needs only the
+`DefId`, which `DefTable::build` already mints, and sits in the body walk for
+_visibility_ — or making `Signatures` extensible after assembly, which gives up
+the read-only rule [`wep-2026-05-26`](./wep-2026-05-26-elaborator-rearchitecture.md)
+rests on.
+
+Two things a first attempt hits: the orphan rule reads a function-local target
+as foreign, because `type_decl_index` holds module-level declarations only; and
+indexing `TraitEnv` alone is _worse_ than the gap, since the header then
+resolves where the signature does not and the diagnostic becomes a panic.

docs/wep-2026-08-12-declaration-identity.md

@@ -467,9 +467,16 @@ a sited entry point a caller with a reference site reaches instead.
 The same derivation in the `Symbol` currency, which §5's `DefId` columns subsume:
 
 - `symbol_named`, `imported`, `lookup_in_module`, `lookup_in_module_with_visited`
-
-One rendering still compared against a declaration's own, which goes when the
-impl index carries `DefId`s:
+- `decl_in_module` — `lookup_in_module` read back as an identity, for the
+  positions no reference site answers: `builtin::f`, a namespace member,
+  `core:rt`'s `panic` at a synthesised call, and a default expression's own
+  module. Each names its module rather than searching for one, so no vantage
+  is supplied.
+
+One rendering still compared against a declaration's own, on the paths that
+name no block: an auto-derived `Eq` / `Ord`, and a method reached through a
+type parameter's bound, whose block monomorphization picks. A dispatch that
+matched a concrete block reads the module off it instead.
 
 - `impl_target_decl_key` — a receiver's newtype chain against an impl's head
 

wado-compiler/src/defs.rs

@@ -83,7 +83,12 @@ pub enum DefKind {
     VariantCase,
     /// A `flags` member.
     FlagsMember,
-    /// A method declared by a trait, a resource, or an effect interface.
+    /// An `impl` block. It writes no name, so nothing can import it and no
+    /// scope answers for it; its identity exists so the methods it declares
+    /// have an owner and its own facts have a key.
+    Impl,
+    /// A method declared by a trait, a resource, an effect interface, or an
+    /// `impl` block.
     Method,
 }
 
@@ -206,20 +211,22 @@ impl DefTable {
             // it would otherwise be the one type in the language with no
             // declaration to name it.
             for item in &ast.items {
-                if let Item::TupleTypeDecl(decl) = item
-                    && !table.by_ast_id.contains_key(&decl.id)
-                {
-                    table.declare(Def {
-                        ast_id: decl.id,
-                        module: module.clone(),
-                        name: crate::name::TUPLE_TYPE_NAME.to_string(),
-                        kind: DefKind::BuiltinType,
-                        visibility: decl.visibility,
-                        span: Some(decl.span),
-                        parent: None,
-                        function_local: false,
-                        members: Vec::new(),
-                    });
+                match item {
+                    Item::TupleTypeDecl(decl) if !table.by_ast_id.contains_key(&decl.id) => {
+                        table.declare(Def {
+                            ast_id: decl.id,
+                            module: module.clone(),
+                            name: crate::name::TUPLE_TYPE_NAME.to_string(),
+                            kind: DefKind::BuiltinType,
+                            visibility: decl.visibility,
+                            span: Some(decl.span),
+                            parent: None,
+                            function_local: false,
+                            members: Vec::new(),
+                        });
+                    }
+                    Item::Impl(block) => table.declare_impl_block(module, block, false),
+                    _ => {}
                 }
             }
             table.declare_members(module, ast);
@@ -256,12 +263,41 @@ impl DefTable {
         }
     }
 
+    /// Identify an `impl` block, which no symbol table row names. Its name is
+    /// empty because it writes none, and no spelling reaches what has none.
+    fn declare_impl_block(
+        &mut self,
+        module: &ModuleSource,
+        block: &crate::ast::ImplBlock,
+        function_local: bool,
+    ) {
+        if self.by_ast_id.contains_key(&block.id) {
+            return;
+        }
+        self.declare(Def {
+            ast_id: block.id,
+            module: module.clone(),
+            name: String::new(),
+            kind: DefKind::Impl,
+            visibility: Visibility::Private,
+            span: Some(block.span),
+            parent: None,
+            function_local,
+            members: Vec::new(),
+        });
+    }
+
     /// Identify a function-local item (`Stmt::Item`) and its members.
     ///
     /// A local `struct` is a declaration like any other — two functions writing
     /// the same spelling declare two of them — so it gets an identity rather
     /// than a mangled storage name standing in for one.
     fn declare_local_item(&mut self, module: &ModuleSource, item: &Item) {
+        if let Item::Impl(block) = item {
+            self.declare_impl_block(module, block, true);
+            self.declare_item_members(module, item);
+            return;
+        }
         let (kind, name) = match item {
             Item::Struct(d) => (DefKind::Struct, &d.name),
             Item::Enum(d) => (DefKind::Enum, &d.name),
@@ -343,6 +379,15 @@ impl DefTable {
                     i.methods.iter().map(|m| (m.id, &m.name, None, m.span)),
                 ),
             ),
+            Item::Impl(b) => (
+                b.id,
+                members(
+                    DefKind::Method,
+                    b.methods
+                        .iter()
+                        .map(|m| (m.id, &m.name, Some(m.visibility), m.span)),
+                ),
+            ),
             _ => return,
         };
         let Some(owner) = self.of_ast_id(owner) else {
@@ -439,6 +484,14 @@ impl DefTable {
     /// nothing.
     ///
     /// This is not a name lookup: the node is already the declaration.
+    /// [`Self::of_ast_id`] for a node the collect pass identified, so a miss is
+    /// a hole in that pass rather than a case to handle.
+    #[must_use]
+    pub fn def_at(&self, id: AstId) -> DefId {
+        self.of_ast_id(id)
+            .unwrap_or_else(|| panic!("{id:?} declares nothing"))
+    }
+
     #[must_use]
     pub fn of_ast_id(&self, id: AstId) -> Option<DefId> {
         self.by_ast_id.get(&id).copied()
@@ -637,6 +690,68 @@ mod tests {
         assert_eq!(field_names(widgets[1]), ["b"]);
     }
 
+    /// An `impl` block is a declaration: two blocks writing the same method
+    /// name declare two methods, and each block owns its own.
+    #[test]
+    fn an_impl_block_and_its_methods_are_declarations() {
+        let source = r#"
+            pub struct Point { x: i32 }
+            pub struct Line { a: i32 }
+            impl Point { pub fn len(&self) -> i32 { return self.x; } }
+            impl Line { pub fn len(&self) -> i32 { return self.a; } }
+        "#;
+        let (defs, module) = build_from_source(source);
+        let blocks: Vec<DefId> = defs
+            .iter()
+            .filter(|d| defs.kind(*d) == DefKind::Impl)
+            .collect();
+        assert_eq!(blocks.len(), 2);
+        assert_ne!(blocks[0], blocks[1]);
+        // No spelling reaches an `impl` block, so it renders none.
+        assert_eq!(defs.name(blocks[0]), "");
+        assert_eq!(defs.module(blocks[0]), &module);
+
+        for block in &blocks {
+            assert_eq!(defs.members(*block).len(), 1);
+            let method = defs.members(*block)[0];
+            assert_eq!(defs.name(method), "len");
+            assert_eq!(defs.kind(method), DefKind::Method);
+            assert_eq!(defs.parent(method), Some(*block));
+        }
+        assert_ne!(defs.members(blocks[0])[0], defs.members(blocks[1])[0]);
+    }
+
+    /// A local `impl` block is declared by the function that writes it, so its
+    /// methods are identified like any other block's.
+    ///
+    /// Identity only: `TraitEnv::build` walks a module's own items, so nothing
+    /// a local block declares is dispatchable yet. Giving it one is what that
+    /// walk needs to reach `Stmt::Item`, not something this table withholds.
+    #[test]
+    fn a_function_local_impl_block_is_a_declaration_of_its_own() {
+        let source = r#"
+            pub fn run() -> i32 {
+                struct Widget { a: i32 }
+                impl Widget { fn get(&self) -> i32 { return self.a; } }
+                let w = Widget { a: 1 };
+                return w.get();
+            }
+        "#;
+        let (defs, _) = build_from_source(source);
+        let block = defs
+            .iter()
+            .find(|d| defs.kind(*d) == DefKind::Impl)
+            .expect("the local impl block is a declaration");
+        assert!(defs.is_function_local(block));
+        assert_eq!(
+            defs.members(block)
+                .iter()
+                .map(|m| defs.name(*m))
+                .collect::<Vec<_>>(),
+            ["get"]
+        );
+    }
+
     /// A cached declaration fact carries a [`DefId`], so a later compile that
     /// re-identifies the same declarations must hand back the same ones — the
     /// stdlib snapshot reads its `ImplSig`s back this way.
@@ -645,6 +760,7 @@ mod tests {
         let source = r#"
             pub struct Point { x: i32, y: i32 }
             pub trait Greet { fn hello(&self) -> i32; }
+            impl Point { pub fn len(&self) -> i32 { return self.x; } }
         "#;
         let (seed, modules, symbols, _) = analyze_source(source);
         let again = DefTable::build_seeded(Some(&seed), &modules, &symbols);