patch 9.0.1906: Vim9: Interfaces should not support class methods and variablesv9.0.1906

Problem:  Vim9: Interfaces should not support class methods and
          variables
Solution: Make sure interface follow the interface specification

Vim9 interface changes to follow the new interface specification:

1) An interface can have only read-only and read-write instance
   variables.
2) An interface can have only public instance methods.
3) An interface cannot have class variables and class methods.
4) An interface cannot have private instance variables and private
   instance methods.
5) A interface can extend another interface using "extends". The
   sub-interface gets all the variables and methods in the super
   interface.

That means:
- Interfaces should not support class methods and variables.
- Adjust error numbers and add additional tests.
- Interface methods can be defined in one of the super classes.
- Interface variables can be defined in one of the super classes.
  and instance variables can be repeated in sub interfaces.
- Check the class variable types with the type in interface.

closes: #13100

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>

1 files changed, 24 insertions, 19 deletions

diff --git a/src/errors.h b/src/errors.h
index 6184037df8..1db70786b3 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -1572,8 +1572,7 @@ EXTERN char e_unknown_printer_font_str[]
 #endif
 EXTERN char e_class_required[]
 	INIT(= N_("E614: Class required"));
-EXTERN char e_object_required[]
-	INIT(= N_("E615: Object required"));
+// E615 unused
 EXTERN char e_object_required_for_argument_nr[]
 	INIT(= N_("E616: Object required for argument %d"));
 #ifdef FEAT_GUI_GTK
@@ -3401,8 +3400,7 @@ EXTERN char e_object_required_found_str[]
 	INIT(= N_("E1327: Object required, found %s"));
 EXTERN char e_constructor_default_value_must_be_vnone_str[]
 	INIT(= N_("E1328: Constructor default value must be v:none: %s"));
-EXTERN char e_cannot_get_object_member_type_from_initializer_str[]
-	INIT(= N_("E1329: Cannot get object member type from initializer: %s"));
+// E1329 unused
 EXTERN char e_invalid_type_for_object_member_str[]
 	INIT(= N_("E1330: Invalid type for object member: %s"));
 EXTERN char e_public_must_be_followed_by_this_or_static[]
@@ -3411,6 +3409,7 @@ EXTERN char e_public_member_name_cannot_start_with_underscore_str[]
 	INIT(= N_("E1332: Public member name cannot start with underscore: %s"));
 EXTERN char e_cannot_access_private_member_str[]
 	INIT(= N_("E1333: Cannot access private member: %s"));
+// E1334 unused
 EXTERN char e_member_is_not_writable_str[]
 	INIT(= N_("E1335: Member is not writable: %s"));
 #endif
@@ -3419,8 +3418,8 @@ EXTERN char e_internal_error_shortmess_too_long[]
 #ifdef FEAT_EVAL
 EXTERN char e_class_member_str_not_found_in_class_str[]
 	INIT(= N_("E1337: Class member \"%s\" not found in class \"%s\""));
-EXTERN char e_member_not_found_on_class_str_str[]
-	INIT(= N_("E1338: Member not found on class \"%s\": %s"));
+EXTERN char e_interface_static_direct_access_str[]
+	INIT(= N_("E1338: Cannot directly access interface \"%s\" static member \"%s\""));
 #endif
 #ifdef FEAT_PROP_POPUP
 EXTERN char e_cannot_add_textprop_with_text_after_using_textprop_with_negative_id[]
@@ -3444,9 +3443,9 @@ EXTERN char e_interface_name_not_found_str[]
 EXTERN char e_not_valid_interface_str[]
 	INIT(= N_("E1347: Not a valid interface: %s"));
 EXTERN char e_member_str_of_interface_str_not_implemented[]
-	INIT(= N_("E1348: Member \"%s\" of interface \"%s\" not implemented"));
-EXTERN char e_function_str_of_interface_str_not_implemented[]
-	INIT(= N_("E1349: Function \"%s\" of interface \"%s\" not implemented"));
+	INIT(= N_("E1348: Member \"%s\" of interface \"%s\" is not implemented"));
+EXTERN char e_method_str_of_interface_str_not_implemented[]
+	INIT(= N_("E1349: Method \"%s\" of interface \"%s\" is not implemented"));
 EXTERN char e_duplicate_implements[]
 	INIT(= N_("E1350: Duplicate \"implements\""));
 EXTERN char e_duplicate_interface_after_implements_str[]
@@ -3480,6 +3479,7 @@ EXTERN char e_incomplete_type[]
 #endif
 EXTERN char e_warning_pointer_block_corrupted[]
 	INIT(= N_("E1364: Warning: Pointer block corrupted"));
+#ifdef FEAT_EVAL
 EXTERN char e_cannot_use_a_return_type_with_new[]
 	INIT(= N_("E1365: Cannot use a return type with the \"new\" function"));
 EXTERN char e_cannot_access_private_method_str[]
@@ -3504,10 +3504,21 @@ EXTERN char e_class_member_str_accessible_only_using_class_str[]
 	INIT(= N_("E1375: Class member \"%s\" accessible only using class \"%s\""));
 EXTERN char e_object_member_str_accessible_only_using_object_str[]
 	INIT(= N_("E1376: Object member \"%s\" accessible only using class \"%s\" object"));
-EXTERN char e_static_member_not_supported_in_interface[]
-	INIT(= N_("E1377: Static member is not supported in an interface"));
 EXTERN char e_method_str_of_class_str_has_different_access[]
-	INIT(= N_("E1378: Access level of method \"%s\" is different in class \"%s\""));
+	INIT(= N_("E1377: Access level of method \"%s\" is different in class \"%s\""));
+EXTERN char e_static_cannot_be_used_in_interface[]
+	INIT(= N_("E1378: Static cannot be used in an interface"));
+EXTERN char e_private_variable_str_in_interface[]
+	INIT(= N_("E1379: Private variable not supported in an interface"));
+EXTERN char e_private_method_str_in_interface[]
+	INIT(= N_("E1380: Private method not supported in an interface"));
+EXTERN char e_interface_cannot_use_implements[]
+	INIT(= N_("E1381: Interface cannot use \"implements\""));
+EXTERN char e_member_str_type_mismatch_expected_str_but_got_str[]
+	INIT(= N_("E1382: Member \"%s\": type mismatch, expected %s but got %s"));
+EXTERN char e_method_str_type_mismatch_expected_str_but_got_str[]
+	INIT(= N_("E1383: Method \"%s\": type mismatch, expected %s but got %s"));
+#endif
 EXTERN char e_cannot_mix_positional_and_non_positional_str[]
 	INIT(= N_("E1400: Cannot mix positional and non-positional arguments: %s"));
 EXTERN char e_fmt_arg_nr_unused_str[]
@@ -3520,12 +3531,6 @@ EXTERN char e_positional_arg_num_type_inconsistent_str_str[]
 	INIT(= N_("E1404: Positional argument %d type used inconsistently: %s/%s"));
 EXTERN char e_invalid_format_specifier_str[]
 	INIT(= N_("E1405: Invalid format specifier: %s"));
-EXTERN char e_member_str_type_mismatch_expected_str_but_got_str[]
-	INIT(= N_("E1406: Member \"%s\": type mismatch, expected %s but got %s"));
-EXTERN char e_method_str_type_mismatch_expected_str_but_got_str[]
-	INIT(= N_("E1407: Method \"%s\": type mismatch, expected %s but got %s"));
 EXTERN char e_aptypes_is_null_nr_str[]
 	INIT(= "E1408: Internal error: ap_types or ap_types[idx] is NULL: %d: %s");
-EXTERN char e_interface_static_direct_access_str[]
-	INIT(= N_("E1409: Cannot directly access interface \"%s\" static member \"%s\""));
-// E1376 - E1399 unused
+// E1384 - E1399 unused