Fix segfault in format_default_value due to unexpected enum/object

Evaluating constants at comptime can result in arrays that contain objects. This
is problematic for printing the default value of constant ASTs containing
objects, because we don't actually know what the constructor arguments were.
Avoid this by not propagating array constants.

Fixes GH-11937

Author: iluuu1994

Zend/zend_compile.c

@@ -1468,7 +1468,7 @@ static bool can_ct_eval_const(zend_constant *c) {
 				&& (CG(compiler_options) & ZEND_COMPILE_WITH_FILE_CACHE))) {
 		return 1;
 	}
-	if (Z_TYPE(c->value) < IS_OBJECT
+	if (Z_TYPE(c->value) < IS_ARRAY
 			&& !(CG(compiler_options) & ZEND_COMPILE_NO_CONSTANT_SUBSTITUTION)) {
 		return 1;
 	}
@@ -1690,7 +1690,7 @@ static bool zend_try_ct_eval_class_const(zval *zv, zend_string *class_name, zend
 	c = &cc->value;
 
 	/* Substitute case-sensitive (or lowercase) persistent class constants */
-	if (Z_TYPE_P(c) < IS_OBJECT) {
+	if (Z_TYPE_P(c) < IS_ARRAY) {
 		ZVAL_COPY_OR_DUP(zv, c);
 		return 1;
 	}

ext/reflection/php_reflection.c

@@ -638,13 +638,6 @@ static int format_default_value(smart_str *str, zval *value) {
 			format_default_value(str, zv);
 		} ZEND_HASH_FOREACH_END();
 		smart_str_appendc(str, ']');
-	} else if (Z_TYPE_P(value) == IS_OBJECT) {
-		zend_object *obj = Z_OBJ_P(value);
-		zend_class_entry *class = obj->ce;
-		ZEND_ASSERT(class->ce_flags & ZEND_ACC_ENUM);
-		smart_str_append(str, class->name);
-		smart_str_appends(str, "::");
-		smart_str_append(str, Z_STR_P(zend_enum_fetch_case_name(obj)));
 	} else {
 		ZEND_ASSERT(Z_TYPE_P(value) == IS_CONSTANT_AST);
 		zend_string *ast_str = zend_ast_export("", Z_ASTVAL_P(value), "");

ext/reflection/tests/gh11937_1.inc

@@ -0,0 +1,13 @@
+<?php
+
+#[Attribute]
+class Attr {
+    public function __construct(public $value) {}
+}
+
+class Foo {
+    public function __construct(public $value) {}
+}
+
+#[Attr(new Foo(TestEnum::CASES))]
+function test() {}

ext/reflection/tests/gh11937_1.phpt

@@ -0,0 +1,30 @@
+--TEST--
+GH-11937: Segfault in format_default_value due to unexpected enum/object
+--FILE--
+<?php
+
+enum TestEnum {
+    case One;
+    case Two;
+    const CASES = [self::One, self::Two];
+}
+
+var_dump(TestEnum::CASES);
+
+require __DIR__ . '/gh11937_1.inc';
+
+echo (new ReflectionFunction('test'))->getAttributes('Attr')[0];
+
+?>
+--EXPECT--
+array(2) {
+  [0]=>
+  enum(TestEnum::One)
+  [1]=>
+  enum(TestEnum::Two)
+}
+Attribute [ Attr ] {
+  - Arguments [1] {
+    Argument #0 [ new \Foo(TestEnum::CASES) ]
+  }
+}

ext/reflection/tests/gh11937_2.inc

@@ -0,0 +1,4 @@
+<?php
+
+#[Attr(FOOS)]
+function test() {}

ext/reflection/tests/gh11937_2.phpt

@@ -0,0 +1,27 @@
+--TEST--
+GH-11937: Segfault in format_default_value due to unexpected enum/object
+--FILE--
+<?php
+
+class Foo {}
+
+const FOOS = [new Foo()];
+
+var_dump(FOOS);
+
+require __DIR__ . '/gh11937_2.inc';
+
+echo (new ReflectionFunction('test'))->getAttributes('Attr')[0];
+
+?>
+--EXPECT--
+array(1) {
+  [0]=>
+  object(Foo)#1 (0) {
+  }
+}
+Attribute [ Attr ] {
+  - Arguments [1] {
+    Argument #0 [ FOOS ]
+  }
+}