js-on-sx: hoist var across nested blocks; var-decls become set!

JS var is function-scoped, but the transpiler only collected
top-level vars and re-emitted (define) everywhere; for-body var
shadowed the outer (un-hoisted) scope. Three-part fix:
1. js-collect-var-names recurses into js-block/js-for/js-while
   /js-do-while/js-if/js-try/js-switch/js-for-of-in;
2. var-kind decls emit (set! ...) instead of (define ...) since
   the binding is already created at function scope;
3. js-block uses js-transpile-stmt-list (no re-hoist) instead of
   js-transpile-stmts.
built-ins/Array: 17/45 → 18/45, String: 77/99 → 78/99.
conformance.sh: 148/148.

lib/js/test262-scoreboard.json

@@ -1,41 +1,37 @@
 {
   "totals": {
-    "pass": 17,
-    "fail": 21,
-    "skip": 5,
-    "timeout": 7,
-    "total": 50,
-    "runnable": 45,
-    "pass_rate": 37.8
+    "pass": 78,
+    "fail": 15,
+    "skip": 1,
+    "timeout": 6,
+    "total": 100,
+    "runnable": 99,
+    "pass_rate": 78.8
   },
   "categories": [
     {
-      "category": "built-ins/Array",
-      "total": 50,
-      "pass": 17,
-      "fail": 21,
-      "skip": 5,
-      "timeout": 7,
-      "pass_rate": 37.8,
+      "category": "built-ins/String",
+      "total": 100,
+      "pass": 78,
+      "fail": 15,
+      "skip": 1,
+      "timeout": 6,
+      "pass_rate": 78.8,
       "top_failures": [
         [
           "Test262Error (assertion failed)",
-          16
+          13
         ],
         [
           "Timeout",
-          7
-        ],
-        [
-          "TypeError: not a function",
-          2
+          6
         ],
         [
           "ReferenceError (undefined symbol)",
-          2
+          1
         ],
         [
-          "Unhandled: Not callable: {:2 43 :1 42 :0 41 :length 3}\\",
+          "SyntaxError (parse/unsupported syntax)",
           1
         ]
       ]
@@ -44,26 +40,22 @@
   "top_failure_modes": [
     [
       "Test262Error (assertion failed)",
-      16
+      13
     ],
     [
       "Timeout",
-      7
-    ],
-    [
-      "TypeError: not a function",
-      2
+      6
     ],
     [
       "ReferenceError (undefined symbol)",
-      2
+      1
     ],
     [
-      "Unhandled: Not callable: {:2 43 :1 42 :0 41 :length 3}\\",
+      "SyntaxError (parse/unsupported syntax)",
       1
     ]
   ],
   "pinned_commit": "d5e73fc8d2c663554fb72e2380a8c2bc1a318a33",
-  "elapsed_seconds": 151.1,
+  "elapsed_seconds": 224.9,
   "workers": 1
 }

lib/js/test262-scoreboard.md

@@ -1,30 +1,28 @@
 # test262 scoreboard
 
 Pinned commit: `d5e73fc8d2c663554fb72e2380a8c2bc1a318a33`
-Wall time: 151.1s
+Wall time: 224.9s
 
-**Total:** 17/45 runnable passed (37.8%). Raw: pass=17 fail=21 skip=5 timeout=7 total=50.
+**Total:** 78/99 runnable passed (78.8%). Raw: pass=78 fail=15 skip=1 timeout=6 total=100.
 
 ## Top failure modes
 
-- **16x** Test262Error (assertion failed)
-- **7x** Timeout
-- **2x** TypeError: not a function
-- **2x** ReferenceError (undefined symbol)
-- **1x** Unhandled: Not callable: {:2 43 :1 42 :0 41 :length 3}\
+- **13x** Test262Error (assertion failed)
+- **6x** Timeout
+- **1x** ReferenceError (undefined symbol)
+- **1x** SyntaxError (parse/unsupported syntax)
 
 ## Categories (worst pass-rate first, min 10 runnable)
 
 | Category | Pass | Fail | Skip | Timeout | Total | Pass % |
 |---|---:|---:|---:|---:|---:|---:|
-| built-ins/Array | 17 | 21 | 5 | 7 | 50 | 37.8% |
+| built-ins/String | 78 | 15 | 1 | 6 | 100 | 78.8% |
 
 ## Per-category top failures (min 10 runnable, worst first)
 
-### built-ins/Array  (17/45 — 37.8%)
+### built-ins/String  (78/99 — 78.8%)
 
-- **16x** Test262Error (assertion failed)
-- **7x** Timeout
-- **2x** TypeError: not a function
-- **2x** ReferenceError (undefined symbol)
-- **1x** Unhandled: Not callable: {:2 43 :1 42 :0 41 :length 3}\
+- **13x** Test262Error (assertion failed)
+- **6x** Timeout
+- **1x** ReferenceError (undefined symbol)
+- **1x** SyntaxError (parse/unsupported syntax)

lib/js/transpile.sx

@@ -116,7 +116,8 @@
           ((js-tag? ast "js-arrow")
             (js-transpile-arrow (nth ast 1) (nth ast 2)))
           ((js-tag? ast "js-program") (js-transpile-stmts (nth ast 1)))
-          ((js-tag? ast "js-block") (js-transpile-stmts (nth ast 1)))
+          ((js-tag? ast "js-block")
+            (cons (js-sym "begin") (js-transpile-stmt-list (nth ast 1))))
           ((js-tag? ast "js-exprstmt") (js-transpile (nth ast 1)))
           ((js-tag? ast "js-empty") nil)
           ((js-tag? ast "js-var")
@@ -509,11 +510,55 @@
     (stmts)
     (cond
       ((empty? stmts) (list))
-      ((and (list? (first stmts)) (js-tag? (first stmts) "js-var") (= (nth (first stmts) 1) "var"))
+      (else
         (append
-          (js-collect-var-decl-names (nth (first stmts) 2))
-          (js-collect-var-names (rest stmts))))
-      (else (js-collect-var-names (rest stmts))))))
+          (js-collect-var-names-stmt (first stmts))
+          (js-collect-var-names (rest stmts)))))))
+
+(define
+  js-collect-var-names-stmt
+  (fn
+    (stmt)
+    (cond
+      ((not (list? stmt)) (list))
+      ((and (js-tag? stmt "js-var") (= (nth stmt 1) "var"))
+        (js-collect-var-decl-names (nth stmt 2)))
+      ((js-tag? stmt "js-block") (js-collect-var-names (nth stmt 1)))
+      ((js-tag? stmt "js-for")
+        (append
+          (js-collect-var-names-stmt (nth stmt 1))
+          (js-collect-var-names-stmt (nth stmt 4))))
+      ((js-tag? stmt "js-for-of-in")
+        (js-collect-var-names-stmt (nth stmt 4)))
+      ((js-tag? stmt "js-while")
+        (js-collect-var-names-stmt (nth stmt 2)))
+      ((js-tag? stmt "js-do-while")
+        (js-collect-var-names-stmt (nth stmt 1)))
+      ((js-tag? stmt "js-if")
+        (append
+          (js-collect-var-names-stmt (nth stmt 2))
+          (if (>= (len stmt) 4) (js-collect-var-names-stmt (nth stmt 3)) (list))))
+      ((js-tag? stmt "js-try")
+        (append
+          (js-collect-var-names-stmt (nth stmt 1))
+          (if (and (>= (len stmt) 3) (list? (nth stmt 2)))
+              (js-collect-var-names-stmt (nth (nth stmt 2) 2))
+              (list))
+          (if (>= (len stmt) 4) (js-collect-var-names-stmt (nth stmt 3)) (list))))
+      ((js-tag? stmt "js-switch")
+        (js-collect-var-names-cases (nth stmt 2)))
+      (else (list)))))
+
+(define
+  js-collect-var-names-cases
+  (fn
+    (cases)
+    (cond
+      ((empty? cases) (list))
+      (else
+        (append
+          (js-collect-var-names (nth (first cases) 2))
+          (js-collect-var-names-cases (rest cases)))))))
 
 (define
   js-dedup-names
@@ -985,12 +1030,12 @@
 
 (define
   js-transpile-var
-  (fn (kind decls) (cons (js-sym "begin") (js-vardecl-forms decls))))
+  (fn (kind decls) (cons (js-sym "begin") (js-vardecl-forms decls (= kind "var")))))
 
 (define
   js-vardecl-forms
   (fn
-    (decls)
+    (decls is-var)
     (cond
       ((empty? decls) (list))
       (else
@@ -1000,10 +1045,10 @@
             ((js-tag? d "js-vardecl")
               (cons
                 (list
-                  (js-sym "define")
+                  (js-sym (if is-var "set!" "define"))
                   (js-sym (nth d 1))
                   (js-transpile (nth d 2)))
-                (js-vardecl-forms (rest decls))))
+                (js-vardecl-forms (rest decls) is-var)))
             ((js-tag? d "js-vardecl-obj")
               (let
                 ((names (nth d 1))
@@ -1014,7 +1059,7 @@
                   (js-vardecl-obj-forms
                     names
                     tmp-sym
-                    (js-vardecl-forms (rest decls))))))
+                    (js-vardecl-forms (rest decls) is-var)))))
             ((js-tag? d "js-vardecl-arr")
               (let
                 ((names (nth d 1))
@@ -1026,7 +1071,7 @@
                     names
                     tmp-sym
                     0
-                    (js-vardecl-forms (rest decls))))))
+                    (js-vardecl-forms (rest decls) is-var)))))
             (else (error "js-vardecl-forms: unexpected decl"))))))))
 
 (define

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 — **`var` declarations hoist out of nested blocks; nested `var` becomes `set!`.** JS `var` is function-scoped, but the transpiler was only collecting top-level vars for hoisting and re-emitting `(define name value)` everywhere — so `for (var i = 0; ...) { var r = i; } r` saw `r` as undefined because the inner `(define r ...)` shadowed the (un-hoisted) outer scope. Three-part fix: (1) `js-collect-var-names` now recurses into `js-block`, `js-for`, `js-for-of-in`, `js-while`, `js-do-while`, `js-if`, `js-try`, `js-switch` to find every `var` decl at function scope; (2) `var`-kind decls emit `set!` (mutate hoisted) instead of `define` (create new binding); (3) `js-block` no longer goes through `js-transpile-stmts` (which re-hoists) — uses plain `js-transpile-stmt-list` so the function-level hoist is the only place a binding is created. built-ins/Array: 17/45 → 18/45, String: 77/99 → 78/99. conformance.sh: 148/148.
+
 - 2026-05-08 — **`arr.length = N` extends the array (no-op for shrink).** `js-list-set!` was a no-op for the `length` key. Added a clause that pads with `js-undefined` via `js-pad-list!` when N > current length. Skipped truncation for now: the `pop-last!` SX primitive doesn't actually mutate the list (verified by direct test — length unchanged after pop), so there's no clean way to shrink in place from SX. Extension covers the common test262 cases (`var x = []; x.length = 5`). built-ins/Array: 16/45 → 17/45. conformance.sh: 148/148.
 
 - 2026-05-08 — **Arrays inherit unknown properties from `Array.prototype` (and onwards via `__proto__`).** `Array.prototype.myprop = 42; var x = []; x.myprop` was returning undefined and `x.hasOwnProperty(...)` raised TypeError, because `js-get-prop` for SX lists fell through to `js-undefined` for any key not in its hardcoded method list. Switched the fallback to `(js-dict-get-walk (get Array "prototype") (js-to-string key))`, which walks Array.prototype → (via the recent `__proto__` fallback) Object.prototype. Now custom Array.prototype properties propagate, and `arr.hasOwnProperty` resolves to `Object.prototype.hasOwnProperty`. built-ins/Array: 14/45 → 16/45. conformance.sh: 148/148.