js-on-sx: js-to-number throws TypeError on non-primitive

Mirrors the earlier js-to-string fix. Number(obj) must throw
if ToPrimitive cannot extract a primitive (both valueOf and
toString return objects). Was returning NaN silently. Replaced
the inner (js-nan-value) fallback with (raise (js-new-call
TypeError ...)).
built-ins/Number: 45/50 → 46/50. conformance.sh: 148/148.

lib/js/runtime.sx

@@ -1049,7 +1049,7 @@
                           (if
                             (not (= (type-of result2) "dict"))
                             (js-to-number result2)
-                            (js-nan-value)))
+                            (raise (js-new-call TypeError (list "Cannot convert object to primitive value")))))
                         (js-nan-value)))))
                 (js-nan-value))))))
       (else 0))))

lib/js/test262-scoreboard.json

@@ -1,29 +1,29 @@
 {
   "totals": {
-    "pass": 44,
-    "fail": 6,
+    "pass": 46,
+    "fail": 2,
     "skip": 0,
-    "timeout": 0,
+    "timeout": 2,
     "total": 50,
     "runnable": 50,
-    "pass_rate": 88.0
+    "pass_rate": 92.0
   },
   "categories": [
     {
-      "category": "built-ins/Object",
+      "category": "built-ins/Number",
       "total": 50,
-      "pass": 44,
-      "fail": 6,
+      "pass": 46,
+      "fail": 2,
       "skip": 0,
-      "timeout": 0,
-      "pass_rate": 88.0,
+      "timeout": 2,
+      "pass_rate": 92.0,
       "top_failures": [
         [
-          "ReferenceError (undefined symbol)",
-          4
+          "Timeout",
+          2
         ],
         [
-          "SyntaxError (parse/unsupported syntax)",
+          "Test262Error (assertion failed)",
           2
         ]
       ]
@@ -31,15 +31,15 @@
   ],
   "top_failure_modes": [
     [
-      "ReferenceError (undefined symbol)",
-      4
+      "Timeout",
+      2
     ],
     [
-      "SyntaxError (parse/unsupported syntax)",
+      "Test262Error (assertion failed)",
       2
     ]
   ],
   "pinned_commit": "d5e73fc8d2c663554fb72e2380a8c2bc1a318a33",
-  "elapsed_seconds": 38.2,
+  "elapsed_seconds": 90.4,
   "workers": 1
 }

lib/js/test262-scoreboard.md

@@ -1,24 +1,24 @@
 # test262 scoreboard
 
 Pinned commit: `d5e73fc8d2c663554fb72e2380a8c2bc1a318a33`
-Wall time: 38.2s
+Wall time: 90.4s
 
-**Total:** 44/50 runnable passed (88.0%). Raw: pass=44 fail=6 skip=0 timeout=0 total=50.
+**Total:** 46/50 runnable passed (92.0%). Raw: pass=46 fail=2 skip=0 timeout=2 total=50.
 
 ## Top failure modes
 
-- **4x** ReferenceError (undefined symbol)
-- **2x** SyntaxError (parse/unsupported syntax)
+- **2x** Timeout
+- **2x** Test262Error (assertion failed)
 
 ## Categories (worst pass-rate first, min 10 runnable)
 
 | Category | Pass | Fail | Skip | Timeout | Total | Pass % |
 |---|---:|---:|---:|---:|---:|---:|
-| built-ins/Object | 44 | 6 | 0 | 0 | 50 | 88.0% |
+| built-ins/Number | 46 | 2 | 0 | 2 | 50 | 92.0% |
 
 ## Per-category top failures (min 10 runnable, worst first)
 
-### built-ins/Object  (44/50 — 88.0%)
+### built-ins/Number  (46/50 — 92.0%)
 
-- **4x** ReferenceError (undefined symbol)
-- **2x** SyntaxError (parse/unsupported syntax)
+- **2x** Timeout
+- **2x** Test262Error (assertion failed)

plans/js-on-sx.md

@@ -158,6 +158,8 @@ Each item: implement → tests → update progress. Mark `[x]` when tests green.
 
 Append-only record of completed iterations. Loop writes one line per iteration: date, what was done, test count delta.
 
+- 2026-05-08 — **`js-to-number` throws TypeError when valueOf+toString both return non-primitive.** Mirrors the earlier `js-to-string` fix. Per spec, `Number(obj)` must throw if `ToPrimitive` cannot extract a primitive. Was returning `NaN` silently. Replaced the inner `(js-nan-value)` fallback with `(raise (js-new-call TypeError ...))`. built-ins/Number: 45/50 → 46/50. conformance.sh: 148/148.
+
 - 2026-05-08 — **`Array.prototype` / `Number.prototype` / etc. inherit from `Object.prototype`.** Per ES, every native prototype's `[[Prototype]]` is `Object.prototype` (and `Function.prototype.[[Prototype]]` is also `Object.prototype`). Was missing those `__proto__` links, so `Object.prototype.isPrototypeOf(Boolean.prototype)` returned false (the explicit isPrototypeOf walks `__proto__`, not the recent fallback). Added 5 `dict-set!` lines to the post-init block at the end of `runtime.sx`. built-ins/Boolean: 22/27 → 23/27, built-ins/Number: 44/50 → 45/50. conformance.sh: 148/148.
 
 - 2026-05-08 — **`delete obj.key` actually removes the key.** `js-delete-prop` was setting the value to `js-undefined` instead of removing the key, so subsequent `'key' in obj` returned true and proto-chain lookup didn't fall through to the parent. Switched to `dict-delete!` (existing SX primitive). Now `delete Boolean.prototype.toString; Boolean.prototype.toString()` correctly walks up to `Object.prototype.toString` and returns `"[object Boolean]"`. built-ins/Boolean: 21/27 → 22/27. conformance.sh: 148/148.