Restore compatibility with XP < 10.8.0

Author: thekid

composer.json

@@ -6,7 +6,7 @@
   "description" : "XP Compiler",
   "keywords": ["module", "xp"],
   "require" : {
-    "xp-framework/core": "^10.8",
+    "xp-framework/core": "^10.0 | ^9.0 | ^8.0 | ^7.0",
     "xp-framework/ast": "dev-feature/php-enums as 7.1.0",
     "php" : ">=7.0.0"
   },

src/main/php/lang/ast/emit/Reflection.class.php

@@ -4,8 +4,11 @@
 
 class Reflection extends Type {
   private $reflect;
+  private static $UNITENUM;
 
-  static function __static() { }
+  static function __static() {
+    self::$UNITENUM= interface_exists(\UnitEnum::class, false);  // Compatibility with XP < 10.8.0
+  }
 
   /** @param string $type */
   public function __construct($type) {
@@ -28,7 +31,7 @@ public function name() { return $this->reflect->name; }
   public function rewriteEnumCase($member) {
     if ($this->reflect->isSubclassOf(Enum::class)) {
       return $this->reflect->getStaticPropertyValue($member, null) instanceof Enum;
-    } else if (!self::$ENUMS && $this->reflect->isSubclassOf(\UnitEnum::class)) {
+    } else if (!self::$ENUMS && self::$UNITENUM && $this->reflect->isSubclassOf(\UnitEnum::class)) {
       $value= $this->reflect->getConstant($member) ?: $this->reflect->getStaticPropertyValue($member, null);
       return $value instanceof \UnitEnum;
     }