fix(compiler): preserve runtime class dispatch and introspection for polymorphic objects

phpunit/code/polymorphic-dispatch.php

@@ -0,0 +1,46 @@
+<?php
+
+class BaseAnimal
+{
+    public static function identify(): string
+    {
+        return 'base';
+    }
+}
+
+class DogAnimal extends BaseAnimal
+{
+    public static function identify(): string
+    {
+        return 'dog';
+    }
+}
+
+function makeAnimal(): BaseAnimal
+{
+    return new DogAnimal();
+}
+
+function getExactClass(): string
+{
+    $dog = new DogAnimal();
+    return get_class($dog);
+}
+
+function getPolymorphicClass(): string
+{
+    $animal = makeAnimal();
+    return get_class($animal);
+}
+
+function callExactStatic(): string
+{
+    $dog = new DogAnimal();
+    return $dog::identify();
+}
+
+function callPolymorphicStatic(): string
+{
+    $animal = makeAnimal();
+    return $animal::identify();
+}

phpunit/src/PolymorphicClassDispatchTest.php

@@ -0,0 +1,44 @@
+<?php
+
+use TypePhp\CompilerTest;
+
+final class PolymorphicClassDispatchTest extends BaseTest
+{
+    public function testPolymorphicClassIntrospectionAndStaticDispatch(): void
+    {
+        global $translator;
+
+        $compiler = CompilerTest::create(TYPEPHP_ROOT_PATH);
+        $translator = $compiler;
+        $source = TYPEPHP_ROOT_PATH . '/phpunit/code/polymorphic-dispatch.php';
+        $compiler->addFiles([$source]);
+        $compiler->prepareFile($source);
+        $code = file_get_contents($compiler->convertFile($source));
+
+        self::assertIsString($code);
+
+        // Exact new object definition get_class() folds to compile-time literal string
+        self::assertMatchesRegularExpression(
+            '/php_getexactclass\(\) \{.*?tmp_var_\d+ = \(get_str\(\d+\)\);/s',
+            $code,
+        );
+
+        // Polymorphic get_class() must NOT fold to BaseAnimal; it must invoke runtime get_class
+        self::assertMatchesRegularExpression(
+            '/php_getpolymorphicclass\(\) \{.*?tmp_var_\d+ = \(php::fn::get_class\(animal\)\);/s',
+            $code,
+        );
+
+        // Exact new object definition static call devirtualizes to cached call
+        self::assertMatchesRegularExpression(
+            '/php_callexactstatic\(\) \{.*?typephp_call_cached\(get_str\(\d+\)/s',
+            $code,
+        );
+
+        // Polymorphic static call must NOT statically bind to BaseAnimal; it must dispatch dynamically
+        self::assertMatchesRegularExpression(
+            '/php_callpolymorphicstatic\(\) \{.*?php::callStaticMethod\([^)]+\)/s',
+            $code,
+        );
+    }
+}

src/Optimizer/FuncCallOptimizer.php

@@ -1118,8 +1118,8 @@ protected function genGetClassOptimized(string $n, Node\Expr\FuncCall $e, array
                 'Native classes do not support runtime class introspection; use `NativeClass::class`',
             );
         }
-        if ($this->isVarExpr($obj) && $this->isStableObject($obj->name)) {
-            return $this->getLiteralString($this->getObjectType($obj->name));
+        if ($this->isVarExpr($obj) && isset($this->context->exactObjects[$obj->name])) {
+            return $this->getLiteralString($this->context->exactObjects[$obj->name]);
         }
         return 'php::fn::get_class(' . $this->parseIdentifier($obj) . ')';
     }

src/Parser/MethodCallTrait.php

@@ -1103,10 +1103,10 @@ protected function parseStaticCall(Expr\StaticCall $expr): string
 
         if (!$this->isNameExpr($expr->class)) {
             if ($this->isVarExpr($expr->class)
-                && $this->isStableObject($class)
+                && isset($this->context->exactObjects[$class])
                 && $this->isIdExpr($expr->name)
             ) {
-                $class = $this->getObjectType($class);
+                $class = $this->context->exactObjects[$class];
                 goto _do_call;
             }
             $classTarget = $this->materializeDynamicStaticCallTarget($expr->class);