Replace static variables with __MemoizeLSB

.hhconfig

@@ -6,4 +6,5 @@ disallow_unsafe_comparisons=true
 decl_override_require_hint=true
 enable_experimental_tc_features=shape_field_check,sealed_classes
 user_attributes=
+disable_static_local_variables = true
 disable_primitive_refinement=true

.travis.sh

@@ -9,7 +9,10 @@ php --version
   cd $(mktemp -d)
   curl https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
 )
+if (hhvm --version | grep -q -- -dev); then
+  rm composer.lock
+fi
 composer install
 
 hh_client
-hhvm vendor/bin/hacktest tests/
+vendor/bin/hacktest tests/

src/core/ComposableElement.php

@@ -259,32 +259,24 @@ final public static function __xhpReflectionAttribute(
     return null;
   }
 
+  <<__MemoizeLSB>>
   final public static function __xhpReflectionAttributes(
   ): Map<string, ReflectionXHPAttribute> {
-    static $cache = Map {};
-    $class = static::class;
-    if (!$cache->containsKey($class)) {
-      $map = Map {};
-      $decl = static::__xhpAttributeDeclaration();
-      foreach ($decl as $name => $attr_decl) {
-        $map[$name] = new ReflectionXHPAttribute($name, $attr_decl);
-      }
-      $cache[$class] = $map;
+    $map = Map {};
+    $decl = static::__xhpAttributeDeclaration();
+    foreach ($decl as $name => $attr_decl) {
+      $map[$name] = new ReflectionXHPAttribute($name, $attr_decl);
     }
-    return $cache[$class];
+    return $map;
   }
 
+  <<__MemoizeLSB>>
   final public static function __xhpReflectionChildrenDeclaration(
   ): ReflectionXHPChildrenDeclaration {
-    static $cache = Map {};
-    $class = static::class;
-    if (!$cache->containsKey($class)) {
-      $cache[$class] = new ReflectionXHPChildrenDeclaration(
-        :xhp::class2element($class),
-        self::emptyInstance()->__xhpChildrenDeclaration(),
-      );
-    }
-    return $cache[$class];
+    return new ReflectionXHPChildrenDeclaration(
+      :xhp::class2element(static::class),
+      self::emptyInstance()->__xhpChildrenDeclaration(),
+    );
   }
 
   final public static function __xhpReflectionCategoryDeclaration(