Allocate on the arena directly

Author: Girgias

Zend/zend_compile.c

@@ -6297,9 +6297,9 @@ static zend_type zend_compile_typename(
 			zend_error_noreturn(E_COMPILE_ERROR, "Nullable type cannot be part of an intersection type");
 		}
 
-		ALLOCA_FLAG(use_heap)
-
-		type_list = do_alloca(ZEND_TYPE_LIST_SIZE(list->children), use_heap);
+		/* Allocate the type list directly on the arena as it must be a type
+		 * list of the same number of elements as the AST list has children */
+		type_list = zend_arena_alloc(&CG(arena), ZEND_TYPE_LIST_SIZE(list->children));
 		type_list->num_types = 0;
 
 		ZEND_ASSERT(list->children > 1);
@@ -6336,18 +6336,12 @@ static zend_type zend_compile_typename(
 			}
 		}
 
-		ZEND_ASSERT(type_list->num_types > 1);
+		ZEND_ASSERT(list->children == type_list->num_types);
 
-		/* TODO Can be arena allocated directly? */
-		zend_type_list *reduced_list = zend_arena_alloc(
-			&CG(arena), ZEND_TYPE_LIST_SIZE(type_list->num_types));
-		memcpy(reduced_list, type_list, ZEND_TYPE_LIST_SIZE(type_list->num_types));
-		ZEND_TYPE_SET_LIST(type, reduced_list);
+		ZEND_TYPE_SET_LIST(type, type_list);
 		ZEND_TYPE_FULL_MASK(type) |= _ZEND_TYPE_ARENA_BIT;
 		/* Inform that the type list is an intersection type */
 		ZEND_TYPE_FULL_MASK(type) |= _ZEND_TYPE_INTERSECTION_BIT;
-
-		free_alloca(type_list, use_heap);
 	} else {
 		type = zend_compile_single_typename(ast);
 	}