fix(rust): resolve Self in scope-resolution type bindings (#2699)

CI regression, caught by `tests / ubuntu / coverage` on 13d5e738 and traced to
the named-receiver Step-1 skip earlier in this PR (59b892ca), not to the three
commits above it — verified by reverting those three and reproducing the
failure unchanged.

`test/integration/resolvers/rust.test.ts > resolves fresh.validate() inside
impl User via Self {} inference` failed: 192/192 on main, 191/192 on this
branch. The fixture calls `fresh.validate()` where `let fresh = Self { .. }`
inside `impl User` — a genuine call to `User::validate`, and a TRUE edge that
the skip deleted.

Root cause is a twin-channel disagreement, not the skip:

  - `type-extractors/rust.ts:142` substitutes `Self` -> the enclosing impl
    type into the TYPE-ENV channel via `findEnclosingImplType`.
  - `languages/rust/interpret.ts` recorded `@type-binding.type` verbatim, so
    the SCOPE-RESOLUTION channel bound `fresh: Self` — a type that does not
    exist, leaving the receiver's type unknown and Step 2 unable to resolve.

`main` passed only because Step 1 still walked the lexical chain for named
receivers: the impl scope binds `validate` by name, so the call resolved BY
ACCIDENT. Stopping that walk turned a latent gap into a lost edge. The fix
closes the gap rather than restoring the accident — `Self` is now substituted
at capture-emit time in `languages/rust/captures.ts`, where the impl node is
reachable, reusing the `findEnclosingImpl` + `syntheticCapture` idiom already
in that file.

CORRECTION to this PR's central claim. "709 removed / 0 added / 0 true edges
lost" was measured on a 762-file TYPESCRIPT corpus and stated without that
qualifier. Rust lost one true edge. The measurement stands for TypeScript; it
did not generalise, and the PR body is being updated to say so.

Scope of the breakage, measured rather than assumed: 1 failure in 2927 tests
across all 51 resolver files. Every other language — Go, Java, C#, Kotlin,
Swift, Python, PHP, Ruby, Dart, C++ — passes, which is why this is a targeted
fix and not a revert of the skip.

Re-baselined `bench/scope-capture` for RUST ONLY (655aed01 -> 7f1240b3); the
other 14 language fingerprints are byte-identical. The drift is the intended
output change and the reason is recorded in the baseline entry, per that
file's own "explain, never re-baseline to make CI green" rule.

Verified: rust resolvers 192/192; all 51 resolver files 2926 passed / 1
skipped / 0 failed; the 8 targeted suites 96/96; all 8 CI bench gates PASS;
`tsc --noEmit` clean; `detect_changes` reports one touched symbol
(`emitRustScopeCaptures`) and no affected flows.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0184RmD24KFJidYqpM7v3XjR

gitnexus/bench/scope-capture/baselines.json

@@ -47,14 +47,15 @@
     "_rebaselined_2563_instance_ownership": "#2563: csharp-using-static adds same-file ownership, local-function, overload, partial-class, and cross-namespace same-name coverage. Prior 75cf380209fa7d1a8a3ec873be1a9424b4e5173be0b08234c2291e8521a9b3c1 -> e05dc27456bde8175948586c9e7689033a378fa40e9ca4ce78cce41fbea0f2f8; scaling 1.058 < 1.5."
   },
   "rust": {
-    "fingerprint": "655aed01cf1b6b84fa0c64d48dfb2526ecb67f47d90f0a91edabacd269a212db",
+    "fingerprint": "7f1240b38457468f06b7931e0c2c578f218f922774d0dc7e2ee6ef3b08d4d689",
     "scaling_budget": 1.5,
     "_rebaselined_dyn_trait_object_2604": "#2604: RUST_SCOPE_QUERY now captures function_signature_item (abstract trait methods, no body) as a scope + declaration, so a &dyn Trait receiver can dispatch a CALLS edge to the trait's own method. Additive capture shift across every bench fixture with a required trait method. Prior df369c5a5f8de7753fc8bab8b4108ef5081750974ea5085ba9a867675ac9eb29 -> f7742f65f14d7d6590df7f16303fc3cc9dc0c233cd80bf90c98b084933cd3846; scaling 1.033 < 1.5.",
     "_rebaselined_callable_flow_2522_review": "PR #2522 review hardening: callable operands retain expression/qualified identity and formals retain signature metadata. Prior 65e5bca66bb1ca117949409e8fb5c80ee69d6f1b5318908eaaecf08da0482e5c -> df369c5a5f8de7753fc8bab8b4108ef5081750974ea5085ba9a867675ac9eb29; scaling 1.065 < 1.5.",
     "_rebaselined_callable_flow_2522_followup": "PR #2522 follow-up: Rust fn-value callable flow facts with invocation/constructor-result suppression. Prior ac610bbe97666bf285923479dd7b43a2fe4c5354aae8df1bcbafdc04fb220f82 -> 65e5bca66bb1ca117949409e8fb5c80ee69d6f1b5318908eaaecf08da0482e5c; scaling 1.024 < 1.5.",
     "_rebaselined": "#1956 tri-review U1: rust-qualified-trait fixture (scoped + generic-of-scoped impl trait paths); bareTypeIdentifier now resolves scoped_type_identifier bases by their name: tail (additive, no existing-fixture drift); linear (~1.04). #1975: + rust-scoped-impl fixture (impl a::Inner / b::Inner inherent scoped impls) \u2014 legacy @definition.impl scoped arm + findEnclosingClassInfo inherent-impl scoped target; rust scope-extractor captures byte-identical. | #942: scope-resolution-only cleanup reworded fixture comments; capture byte-positions shift, capture LOGIC unchanged.",
     "_note": "PR #1934: F66/F68 let-binding pattern narrowing; F71 union (Struct-labeled, now materialized via legacy @definition.struct + resolvable); F72 macro FULLY WIRED \u2014 @declaration.macro/@reference.macro + MacroRegistry \u2192 USES edges to Macro nodes (never a same-named fn). + rust-macro / rust-union fixtures and merged with origin/main #1975 rust-scoped-impl; fingerprint re-baselined (scaling ~0.99, fixture_count 126). #1992: + rust-nested-tail-collision-generic and rust-generic-impl-same-method-name (F3) fixtures \u2014 pure fixture-corpus drift, no scope-extractor change; fixture_count 127->129, fingerprint 56ffc1c0->b00aea0f.",
-    "_rebaselined_import_disambiguation_2514": "#2514: added rust-import-* and rust-dup-* fixtures under lang-resolution for the range-binding ambiguity latch + import-disambiguated resolution (for-loops / struct destructuring across explicit/aliased/glob use imports). emitRustScopeCaptures is unchanged; the corpus fingerprint shifts purely because the fixture set grew (130 -> 174). Prior f7742f65f14d7d6590df7f16303fc3cc9dc0c233cd80bf90c98b084933cd3846 -> 655aed01cf1b6b84fa0c64d48dfb2526ecb67f47d90f0a91edabacd269a212db; scaling 1.06 < 1.5."
+    "_rebaselined_import_disambiguation_2514": "#2514: added rust-import-* and rust-dup-* fixtures under lang-resolution for the range-binding ambiguity latch + import-disambiguated resolution (for-loops / struct destructuring across explicit/aliased/glob use imports). emitRustScopeCaptures is unchanged; the corpus fingerprint shifts purely because the fixture set grew (130 -> 174). Prior f7742f65f14d7d6590df7f16303fc3cc9dc0c233cd80bf90c98b084933cd3846 -> 655aed01cf1b6b84fa0c64d48dfb2526ecb67f47d90f0a91edabacd269a212db; scaling 1.06 < 1.5.",
+    "_rebaselined_self_type_binding_2714": "#2714: a Rust `Self` type binding now records the enclosing impl's type instead of the literal 'Self'. `let fresh = Self { .. }` inside `impl User` binds `fresh: User`; recorded verbatim it bound `fresh: Self`, which resolves to nothing. The type-env channel already substituted this (type-extractors/rust.ts findEnclosingImplType); the scope-resolution channel did not, so the two disagreed. The gap was invisible while lookupCore Step 1 still walked the lexical chain for NAMED receivers \u2014 the impl scope binds the method by name, so fresh.validate() resolved by accident \u2014 and became a lost CALLS edge when #2714 stopped that walk. Only the rust fingerprint moves; the other 14 languages are byte-identical."
   },
   "php": {
     "fingerprint": "4a688fa5a7016546f7f3c6d44de023608ae80c5b0e3670c16f6e61b3632608fd",

gitnexus/src/core/ingestion/languages/rust/captures.ts

@@ -123,6 +123,31 @@ export function emitRustScopeCaptures(
       }
     }
 
+    // `Self` in a type binding names the enclosing impl's type, not a type
+    // called "Self". `let fresh = Self { … }` inside `impl User` binds
+    // `fresh: User`; recorded verbatim it binds `fresh: Self`, which resolves
+    // to nothing and leaves the receiver's type unknown.
+    //
+    // The type-env channel already substitutes this
+    // (`type-extractors/rust.ts` → `findEnclosingImplType`); the
+    // scope-resolution channel did not, so the two disagreed. That went
+    // unnoticed while `lookupCore` Step 1 still walked the lexical chain for
+    // named receivers — the impl scope binds the method by name, so
+    // `fresh.validate()` resolved by accident. #2714 stopped that walk for
+    // named receivers and the gap became a lost edge (#2699 follow-up).
+    const tbTypeNode = nodeMap['@type-binding.type'];
+    if (grouped['@type-binding.type']?.text === 'Self' && tbTypeNode !== undefined) {
+      const implNode = findEnclosingImpl(tbTypeNode);
+      const implTypeNode = implNode?.childForFieldName('type') ?? null;
+      if (implTypeNode !== null) {
+        grouped['@type-binding.type'] = syntheticCapture(
+          '@type-binding.type',
+          tbTypeNode,
+          implTypeNode.text,
+        );
+      }
+    }
+
     // Hoist return-type bindings from impl block functions to module level.
     // The auto-hoist in the scope-extractor places a type binding whose
     // anchor matches its innermost scope on the parent scope. By using the