Improve error message when overriding untyped property with typed property (phpGH-16866)

Author: chx

Zend/tests/type_declarations/mixed/inheritance/mixed_property_inheritance_error7.phpt

@@ -15,4 +15,4 @@ class Bar extends Foo
 
 ?>
 --EXPECTF--
-Fatal error: Type of Bar::$property1 must not be defined (as in class Foo) in %s on line %d
+Fatal error: Type of Bar::$property1 must be omitted to match the parent definition in class Foo in %s on line %d

Zend/tests/type_declarations/typed_properties_035.phpt

@@ -11,4 +11,4 @@ class Baz extends Foo{
 }
 ?>
 --EXPECTF--
-Fatal error: Type of Baz::$bar must not be defined (as in class Foo) in %s on line 6
+Fatal error: Type of Baz::$bar must be omitted to match the parent definition in class Foo in %s on line 6

Zend/zend_inheritance.c

@@ -1507,7 +1507,7 @@ static void do_inherit_property(zend_property_info *parent_info, zend_string *ke
 				}
 			} else if (UNEXPECTED(ZEND_TYPE_IS_SET(child_info->type) && !ZEND_TYPE_IS_SET(parent_info->type))) {
 				zend_error_noreturn(E_COMPILE_ERROR,
-						"Type of %s::$%s must not be defined (as in class %s)",
+						"Type of %s::$%s must be omitted to match the parent definition in class %s",
 						ZSTR_VAL(ce->name),
 						ZSTR_VAL(key),
 						ZSTR_VAL(parent_info->ce->name));