PurHur · PurHur · May 25, 2026 · May 25, 2026
diff --git a/README.md b/README.md
@@ -41,7 +41,7 @@ Presenter script and troubleshooting: [`docs/GETTING-STARTED.md`](docs/GETTING-S
 | **003-MiniWebApp** VM + AOT link | ✅ |
 | **003** AOT execute (all routes) | 🚧 partial — home ✅ ([#1044](https://github.com/PurHur/php-compiler/issues/1044)) |
 | Self-host **M0–M1** | ✅ |
-| Self-host **M2** spine | 🚧 **579** / 586 units ([#1492](https://github.com/PurHur/php-compiler/issues/1492)) |
+| Self-host **M2** spine | 🚧 **582** / 586 units ([#1492](https://github.com/PurHur/php-compiler/issues/1492)) |
 | Full Zend PHP compatibility | ❌ — subset only (matrices in `docs/`, not on status site) |
 
 MiniWebApp gates: [docs/miniwebapp-gates.md](docs/miniwebapp-gates.md) ([#472](https://github.com/PurHur/php-compiler/issues/472)). Docker image: `php-compiler:22.04-dev`.
@@ -141,7 +141,7 @@ Matrix details: [docs/local-ci-matrix.md](docs/local-ci-matrix.md).
 |-----------|----------------|--------|
 | **M0 — Bundled subset runs** | ~**109** literal `require_once` units in `test/selfhost/compiler_minimal/main.php` compile+link under AOT; native binary prints `compiler_minimal bundle OK` | ✅ ([#557](https://github.com/PurHur/php-compiler/issues/557), [#913](https://github.com/PurHur/php-compiler/issues/913)) |
 | **M1 — Compiler-shaped bundle** | Same bundle **lints** as one translation unit; **compile-smoke** links a tiny fixture and runs AOT echo (`compiler smoke`); driver smoke bundles `bin/compile.php`-adjacent units | ✅ ([#1025](https://github.com/PurHur/php-compiler/issues/1025)) |
-| **M2 — Full top-level `lib/` + spine** | All **14** top-level `lib/*.php` lint ✅; **`compiler_lib_spine_smoke`** (**579** / **586** inventory units) native link ✅; grow toward full `bin/vm.php` path | 🚧 ~99% of inventory |
+| **M2 — Full top-level `lib/` + spine** | All **14** top-level `lib/*.php` lint ✅; **`compiler_lib_spine_smoke`** (**582** / **586** inventory units) native link ✅; grow toward full `bin/vm.php` path | 🚧 ~99% of inventory |
 | **M3 — Native compiles PHP** | Self-host bundle links; HelloWorld AOT **runs** natively; **compile emit still Zend fallback** | 🚧 partial |
 | **M4 — Bootstrap loop** | Native toolchain rebuilds the **next** compiler sources | ⬜ |
 | **M5 — Full self-host** | Real `bin/vm.php` / `bin/compile.php` on full inventory; **no Zend bootstrap** | ⬜ **north star** ([#1492](https://github.com/PurHur/php-compiler/issues/1492)) |

diff --git a/docs/bootstrap-selfhost.md b/docs/bootstrap-selfhost.md
@@ -20,7 +20,7 @@
 | Self-host probe in full CI | `./script/ci-local.sh` (LLVM tail) | ✅ default-on when LLVM 9 present; `BOOTSTRAP_SELFHOST_PROBE_GATE=0` to skip ([#829](https://github.com/PurHur/php-compiler/issues/829)) |
 | Wave gate in full CI | `./script/ci-local.sh` (LLVM tail) | ✅ default-on when LLVM 9 present; `BOOTSTRAP_WAVE_CHECK=0` to skip; `./script/bootstrap-wave-check.sh --fail-fast` |
 | Self-host native link | `./script/bootstrap-selfhost-link.sh` | ✅ `build/selfhost` prints `compiler_minimal bundle OK` ([#557](https://github.com/PurHur/php-compiler/issues/557), [#913](https://github.com/PurHur/php-compiler/issues/913)) |
-| M2 lib spine smoke lint | `php bin/compile.php -l test/selfhost/compiler_lib_spine_smoke/main.php` | ✅ **579** units ([#1492](https://github.com/PurHur/php-compiler/issues/1492), [#1419](https://github.com/PurHur/php-compiler/issues/1419)
+| M2 lib spine smoke lint | `php bin/compile.php -l test/selfhost/compiler_lib_spine_smoke/main.php` | ✅ **582** units ([#1492](https://github.com/PurHur/php-compiler/issues/1492), [#1419](https://github.com/PurHur/php-compiler/issues/1419)
 | M2 lib spine smoke native run | `./script/bootstrap-selfhost-lib-spine-smoke-link.sh` or `BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke` | ✅ `build/selfhost-lib-spine-smoke` prints `compiler_lib_spine_smoke bundle OK` |
 | M3 HelloWorld self-host probe lint | `php bin/compile.php -l test/selfhost/compiler_helloworld_smoke/main.php` | ✅ `compiler_compile_smoke` spine + `helloworld_compile_smoke` driver (linkable) |
 | M3 HelloWorld compile driver lint | `php bin/compile.php -l test/selfhost/compiler_helloworld_smoke/compile_driver.php` | ✅ `Runtime::parseAndCompile` + mode-file dispatch (native link opt-in) |

diff --git a/docs/fixtures/m2-spine-open-issues.json b/docs/fixtures/m2-spine-open-issues.json
@@ -1,3 +1 @@
-[
-  {"number": 1543, "title": "M2 spine: add `ext/standard/VmSplAutoload.php` to compiler_lib_spine_smoke"}
-]
+[]
diff --git a/docs/pages/development-status.md b/docs/pages/development-status.md
@@ -15,7 +15,7 @@ permalink: /development-status.html
 | **Overall progress** | ~**50%** toward web-capable + self-hosting compiler (indicative) |
 | **Wave 3 (May 2026)** | Language **10/13** · Stdlib **12/13** ([#1380](https://github.com/PurHur/php-compiler/issues/1380)) |
 | **North Star 1** | Reference web app — VM ✅ · AOT link ✅ · AOT execute **partial** ([#1044](https://github.com/PurHur/php-compiler/issues/1044)) |
-| **North Star 2** | Self-compile — M0–M1 ✅ · M2 spine **579/586** · M5 ⬜ ([#1492](https://github.com/PurHur/php-compiler/issues/1492)
+| **North Star 2** | Self-compile — M0–M1 ✅ · M2 spine **582/586** · M5 ⬜ ([#1492](https://github.com/PurHur/php-compiler/issues/1492)
 | **Not Zend parity** | Subset compiler (not full Zend PHP) |
 
 [← Visual overview](index.html) · [Repository](https://github.com/PurHur/php-compiler)
@@ -51,7 +51,7 @@ Indicative composite toward a **web-capable, self-hosting** compiler (not line-c
 | **Stdlib** | ~58% | Wave-3 batch ([#1367](https://github.com/PurHur/php-compiler/issues/1367)–[#1379](https://github.com/PurHur/php-compiler/issues/1379)): **13/13** closed on master |
 | **Web AOT** (build, deploy) | ~65% | Project link ✅; home-route execute ✅; PATH_INFO / layout chain 🚧 |
 | **Reference app** (MiniWebApp) | ~55% | VM ✅; AOT link ✅; AOT execute **partial** |
-| **Self-host** (North Star 2, M0–M5) | ~98% | M0–M1 ✅; M2 spine **579/586**; M3 partial (native run ✅, Zend emit); M4–M5 ⬜ — [self-host-target.md](https://github.com/PurHur/php-compiler/blob/master/docs/self-host-target.md
+| **Self-host** (North Star 2, M0–M5) | ~99% | M0–M1 ✅; M2 spine **582/586**; M3 partial (native run ✅, Zend emit); M4–M5 ⬜ — [self-host-target.md](https://github.com/PurHur/php-compiler/blob/master/docs/self-host-target.md
 
 **Overall (indicative): ~52%** toward the stated north stars below.
 
@@ -200,7 +200,7 @@ Zend PHP still runs `bin/compile.php` during bootstrap. The output is a **curate
 |-----------|---------|--------|
 | **M0 — Bundled subset runs** | ~109 literal `require_once` units in `test/selfhost/compiler_minimal/main.php` → `build/selfhost` prints `compiler_minimal bundle OK` | ✅ [#557](https://github.com/PurHur/php-compiler/issues/557), [#913](https://github.com/PurHur/php-compiler/issues/913) |
 | **M1 — Compiler-shaped bundle** | Bundled `Compiler.php` AOT lint; compile-smoke native link + AOT echo (`compiler smoke`); driver smoke toward `bin/compile.php` | ✅ [#1025](https://github.com/PurHur/php-compiler/issues/1025), [#1095](https://github.com/PurHur/php-compiler/issues/1095) |
-| **M2 — Lib spine growth** | `compiler_lib_spine_smoke` bundle toward full `bin/vm.php` inventory (**586** files) | 🚧 **579** / 586 units (~99%; [#1492](https://github.com/PurHur/php-compiler/issues/1492)
+| **M2 — Lib spine growth** | `compiler_lib_spine_smoke` bundle toward full `bin/vm.php` inventory (**586** files) | 🚧 **582** / 586 units (~99%; [#1492](https://github.com/PurHur/php-compiler/issues/1492)
 | **M3 — Native compiles PHP** | Self-hosted bundle links; HelloWorld AOT **runs** natively; **emit still uses Zend** `bin/compile.php` fallback | 🚧 partial ([#1492](https://github.com/PurHur/php-compiler/issues/1492)) |
 | **M4 — Bootstrap loop** | Native toolchain rebuilds the **next** compiler sources (same tree, new revision) | ⬜ |
 | **M5 — Full self-host** | Real `bin/vm.php` / `bin/compile.php` path on full inventory; **no Zend bootstrap** | ⬜ **north star** ([#1492](https://github.com/PurHur/php-compiler/issues/1492)) |
@@ -210,7 +210,7 @@ Zend PHP still runs `bin/compile.php` during bootstrap. The output is a **curate
 | Set | ~Files | Notes |
 |-----|--------|-------|
 | `compiler_minimal` bundle (M0) | **109** | Literal `require_once` closure |
-| `compiler_lib_spine_smoke` (M2) | **579** | vm.php-path lib/ + ext/standard growth bundl
+| `compiler_lib_spine_smoke` (M2) | **582** | vm.php-path lib/ + ext/standard growth bundl
 | Top-level `lib/*.php` | **14** | Per-file AOT lint ✅ |
 | Full vm.php inventory | **586** | Phase A inventory (`php script/bootstrap-inventory.php`) |
 
@@ -245,7 +245,7 @@ Details: [self-host-target.md](https://github.com/PurHur/php-compiler/blob/maste
 | Native link + run | `./script/bootstrap-selfhost-link.sh` | ✅ M0 |
 | Compile smoke link | `make bootstrap-selfhost-compile-smoke` | ✅ M1 |
 | Compile smoke AOT echo | `make bootstrap-selfhost-compile-smoke-run` | ✅ M1 |
-| M2 spine native link | `BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke` | ✅ `compiler_lib_spine_smoke bundle OK` (**579** units
+| M2 spine native link | `BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke` | ✅ `compiler_lib_spine_smoke bundle OK` (**582** units
 | M3 HelloWorld probe | `make bootstrap-selfhost-helloworld` | 🚧 partial — native **run** ✅; emit Zend fallback |
 | Wave gate | `./script/bootstrap-wave-check.sh` | ✅ locally / Docker; GHA workflow disabled |
 | Next includes probe | `php script/bootstrap-selfhost-next-includes.php` | 🚧 bundle growth |

diff --git a/docs/roadmap-wave3.md b/docs/roadmap-wave3.md
@@ -17,7 +17,7 @@ Regenerate capability truth: `php script/capability-matrix.php`, `php script/cap
 
 Related merges outside this wave: `goto` ([#1228](https://github.com/PurHur/php-compiler/issues/1228) / [#1333](https://github.com/PurHur/php-compiler/pull/1333)), anonymous classes ([#1233](https://github.com/PurHur/php-compiler/issues/1233) / [#1386](https://github.com/PurHur/php-compiler/pull/1386)).
 
-**M2 spine:** **579** / **586** inventory (`compiler_lib_spine_smoke` native link ✅; [#1492](https://github.com/PurHur/php-compiler/issues/1492), M2 batches [#1419](https://github.com/PurHur/php-compiler/issues/1419), [#1497](https://github.com/PurHur/php-compiler/issues/1497)). Target doc: [self-host-target.md](self-host-target.m
+**M2 spine:** **582** / **586** inventory (`compiler_lib_spine_smoke` native link ✅; [#1492](https://github.com/PurHur/php-compiler/issues/1492), M2 batches [#1419](https://github.com/PurHur/php-compiler/issues/1419), [#1497](https://github.com/PurHur/php-compiler/issues/1497)). Target doc: [self-host-target.md](self-host-target.m
 
 ## Language (#1354–#1366)
 

diff --git a/docs/self-host-target.md b/docs/self-host-target.md
@@ -34,8 +34,8 @@ That is **M5**. Everything below is the honest path from today’s bootstrap to
 | Layer | Today | Target |
 |-------|-------|--------|
 | **Bootstrap driver** | Zend runs `php bin/compile.php` | Compiled `bin/compile.php` |
-| **Bundle size** | **579** curated `require_once` in spine smoke (108 minimal overlap + **471** M2-only) | **586** inventory files |
-| **Inventory coverage** | **~99%** of vm.php path in spine smoke (**579/586**) | **100%*
+| **Bundle size** | **582** curated `require_once` in spine smoke (108 minimal overlap + **474** M2-only) | **586** inventory files |
+| **Inventory coverage** | **~99%** of vm.php path in spine smoke (**582/586**) | **100%*
 | **HelloWorld** | Native **run** ✅; **emit** still Zend fallback | Native compile + emit |
 | **Bootstrap loop (M4)** | Gen-1 link + gen-2 Zend partial | Native gen-2 emit + full tree rebuild |
 | **Vendor** | `composer install` + patches on host | Prelinked artifacts only |
@@ -61,7 +61,7 @@ That is **M5**. Everything below is the honest path from today’s bootstrap to
 |-----------|----------------|--------|-----|
 | **M0** | AOT can link a **small** honest `lib/` subset | ✅ | 100% |
 | **M1** | Bundle is **compiler-shaped** (lint + compile-smoke) | ✅ | 100% |
-| **M2** | Spine grows toward full `bin/vm.php` inventory | 🚧 **579/586** units | **~99%*
+| **M2** | Spine grows toward full `bin/vm.php` inventory | 🚧 **582/586** units | **~99%*
 | **M3** | Self-host binary **compiles external PHP** (HelloWorld) without Zend emit | 🚧 partial | **~45%** |
 | **M4** | Self-host binary **rebuilds** the next compiler tree | ⬜ | 0% |
 | **M5** | Full self-host; Zend retired from loop | ⬜ north star | 0% |
@@ -72,7 +72,7 @@ That is **M5**. Everything below is the honest path from today’s bootstrap to
 
 | Indicator | Formula | May 2026 |
 |-----------|---------|----------|
-| **M2 spine progress** | `require_once` units in `compiler_lib_spine_smoke` ÷ Phase A inventory file count | **579 / 586 ≈ 99%*
+| **M2 spine progress** | `require_once` units in `compiler_lib_spine_smoke` ÷ Phase A inventory file count | **582 / 586 ≈ 99%*
 | **Public “Self-host” row** | Same M2 ratio until M3–M5 gates add weight ([`development-status.md`](pages/development-status.md)) | **~61%** |
 | **Composite (internal)** | Milestone weights in table above (M0–M1 = 100%, M2 = spine %, M3–M5 = gate %) | **~54%** |
 
@@ -124,7 +124,7 @@ Parallel batches ([#1419](https://github.com/PurHur/php-compiler/issues/1419), [
 | Entry | Units | Role |
 |-------|------:|------|
 | `test/selfhost/compiler_minimal/main.php` | **109** | M0 core |
-| `test/selfhost/compiler_lib_spine_smoke/main.php` | **579** | M2 growth (ext/standard + Vm* spine batch
+| `test/selfhost/compiler_lib_spine_smoke/main.php` | **582** | M2 growth (ext/standard + Vm* spine batch
 | `test/selfhost/compiler_helloworld_smoke/` | — | M3 probe + compile driver |
 | `test/selfhost/bootstrap_loop_smoke/` | — | M4 scaffold (gen-1→gen-2 loop probe; [#1498](https://github.com/PurHur/php-compiler/issues/1498)) |
 

diff --git a/ext/standard/VmSplAutoload.php b/ext/standard/VmSplAutoload.php
@@ -6,10 +6,13 @@
 
 use PHPCompiler\Func\PHP as PhpFunc;
 use PHPCompiler\VM\Context;
+use PHPCompiler\VM\ObjectEntry;
 use PHPCompiler\VM\Variable;
 
 /**
  * spl_autoload_register() stack and callback invocation (issue #1369).
+ *
+ * Runner classes avoid Expr_Closure so this unit AOT-lints in the self-host spine (#1056, #1543).
  */
 final class VmSplAutoload
 {
@@ -40,7 +43,7 @@ public static function runStack(Context $ctx, string $className): bool
             return true;
         }
         foreach ($ctx->splAutoloadCallbacks as $runner) {
-            $runner($ctx, $className);
+            $runner->run($ctx, $className);
             if (isset($ctx->classes[$lc])) {
                 return true;
             }
@@ -49,10 +52,7 @@ public static function runStack(Context $ctx, string $className): bool
         return false;
     }
 
-    /**
-     * @return callable
-     */
-    private static function bindCallback(Context $ctx, Variable $callback)
+    private static function bindCallback(Context $ctx, Variable $callback): SplAutoloadRunner
     {
         $callback = $callback->resolveIndirect();
         if (Variable::TYPE_STRING === $callback->type) {
@@ -71,35 +71,22 @@ private static function bindCallback(Context $ctx, Variable $callback)
         );
     }
 
-    /**
-     * @return callable
-     */
-    private static function bindFunction(Context $ctx, string $name)
+    private static function bindFunction(Context $ctx, string $name): SplAutoloadRunner
     {
         $func = VmUserCall::resolveStringCallback($ctx, $name);
 
-        return static function (Context $ctx, string $className) use ($func): void {
-            self::invokeFunction($ctx, $func, $className);
-        };
+        return new SplAutoloadFunctionRunner($func);
     }
 
-    /**
-     * @return callable
-     */
-    private static function bindStaticName(Context $ctx, string $callable)
+    private static function bindStaticName(Context $ctx, string $callable): SplAutoloadRunner
     {
         [$className, $methodName] = explode('::', $callable, 2);
         $func = self::resolveStaticMethod($ctx, $className, $methodName);
 
-        return static function (Context $ctx, string $className) use ($func): void {
-            self::invokeFunction($ctx, $func, $className);
-        };
+        return new SplAutoloadFunctionRunner($func);
     }
 
-    /**
-     * @return callable
-     */
-    private static function bindArrayCallable(Context $ctx, Variable $callable)
+    private static function bindArrayCallable(Context $ctx, Variable $callable): SplAutoloadRunner
     {
         $table = $callable->toArray();
         $idx0 = new Variable(Variable::TYPE_INTEGER);
@@ -118,9 +105,7 @@ private static function bindArrayCallable(Context $ctx, Variable $callable)
         if (Variable::TYPE_STRING === $target->type) {
             $func = self::resolveStaticMethod($ctx, $target->toString(), $method);
 
-            return static function (Context $ctx, string $className) use ($func): void {
-                self::invokeFunction($ctx, $func, $className);
-            };
+            return new SplAutoloadFunctionRunner($func);
         }
         if (Variable::TYPE_OBJECT === $target->type) {
             $class = $target->toObject()->class;
@@ -130,9 +115,7 @@ private static function bindArrayCallable(Context $ctx, Variable $callable)
             }
             $func = $class->methods[$methodLc];
 
-            return static function (Context $ctx, string $className) use ($func, $target): void {
-                self::invokeInstanceMethod($ctx, $func, $target->toObject(), $className);
-            };
+            return new SplAutoloadInstanceMethodRunner($func, $target->toObject());
         }
         throw new \LogicException(
             'spl_autoload_register() array callback first element must be a class name string or object'
@@ -160,24 +143,41 @@ private static function resolveStaticMethod(Context $ctx, string $className, str
 
         return $func;
     }
+}
+
+interface SplAutoloadRunner
+{
+    public function run(Context $ctx, string $className): void;
+}
+
+final class SplAutoloadFunctionRunner implements SplAutoloadRunner
+{
+    public function __construct(private PhpFunc $func)
+    {
+    }
 
-    private static function invokeFunction(Context $ctx, PhpFunc $func, string $className): void
+    public function run(Context $ctx, string $className): void
     {
         $arg = new Variable();
         $arg->string($className);
-        $ctx->runtime->vm->invokePhpFunction($func, $arg);
+        $ctx->runtime->vm->invokePhpFunction($this->func, $arg);
     }
+}
 
-    private static function invokeInstanceMethod(
-        Context $ctx,
-        PhpFunc $func,
-        \PHPCompiler\VM\ObjectEntry $receiver,
-        string $className
-    ): void {
+final class SplAutoloadInstanceMethodRunner implements SplAutoloadRunner
+{
+    public function __construct(
+        private PhpFunc $func,
+        private ObjectEntry $receiver
+    ) {
+    }
+
+    public function run(Context $ctx, string $className): void
+    {
         $recv = new Variable();
-        $recv->object($receiver);
+        $recv->object($this->receiver);
         $arg = new Variable();
         $arg->string($className);
-        $ctx->runtime->vm->invokePhpFunction($func, $recv, $arg);
+        $ctx->runtime->vm->invokePhpFunction($this->func, $recv, $arg);
     }
 }
diff --git a/lib/VM/Context.php b/lib/VM/Context.php
@@ -21,7 +21,7 @@ class Context {
     public array $enums = [];
     /** @var list<callable(string): bool> */
     public array $classAutoloaders = [];
-    /** @var list<callable(Context, string): void> spl_autoload_register() stack (#1369) */
+    /** @var list<\PHPCompiler\ext\standard\SplAutoloadRunner> spl_autoload_register() stack (#1369) */
     public array $splAutoloadCallbacks = [];
     /** @var array<string, true> */
     private array $loadedCompileUnits = [];