Don't mess NULL and UNDEF default value back and force. Set proper value in first place.

Author: dstogov

Zend/zend_API.c

@@ -3655,10 +3655,6 @@ ZEND_API int zend_declare_typed_property(zend_class_entry *ce, zend_string *name
 		}
 	}
 
-	if (Z_ISUNDEF_P(property) && (!optional_type || allow_null)) {
-		ZVAL_NULL(property);
-	}
-
 	if (!(access_type & ZEND_ACC_PPP_MASK)) {
 		access_type |= ZEND_ACC_PUBLIC;
 	}

Zend/zend_compile.c

@@ -5615,6 +5615,8 @@ void zend_compile_prop_decl(zend_ast *ast, zend_ast *type_ast) /* {{{ */
 							zend_get_type_by_const(optional_type));
 				}
 			}
+		} else if (!optional_type || allow_null) {
+			ZVAL_NULL(&value_zv);
 		} else {
 			ZVAL_UNDEF(&value_zv);
 		}