patch 9.0.1898: Vim9: restrict access to static varsv9.0.1898

Problem:  Vim9: restrict access to static vars and methods
Solution: Class members are accesible only from the class where they are
          defined.

Based on the #13004 discussion, the following changes are made:

    1) Static variables and methods are accessible only using the class
       name and inside the class where they are defined.
    2) Static variables and methods can be used without the class name in
       the class where they are defined.
    3) Static variables of a super class are not copied to the sub class.
    4) A sub class can declare a class variable with the same name as the
       super class.
    5) When a method or member is found during compilation, use more
       specific error messages.

This aligns the Vim9 class variable/method implementation with the Dart
implementation.

Also while at it, ignore duplicate class and object methods.

The access level of an object method can however be changed in a
subclass.

For the tests, use the new CheckSourceFailure() function instead of the
CheckScriptFailure() function in the tests.

closes: #13086

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

1 files changed, 1 insertions, 4 deletions

diff --git a/src/eval.c b/src/eval.c
index dd7b8d8f33..523546957e 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1596,10 +1596,7 @@ get_lval(
 
 		if (lp->ll_valtype == NULL)
 		{
-		    if (v_type == VAR_OBJECT)
-			semsg(_(e_object_member_not_found_str), key);
-		    else
-			semsg(_(e_class_member_not_found_str), key);
+		    member_not_found_msg(cl, v_type, key, p - key);
 		    return NULL;
 		}
 	    }