patch 9.0.2002: Vim9: need cleanup of class related interface code

Problem:  Vim9: need cleanup of class related interface code
Solution: Remove the unused class variable and class method related code
          for interfaces.

Remove unused class variable and class method related code for
interfaces.

Refactor the code.

Optimize the object/class member double lookup in compile_lhs().

Change unused global functions to static functions.

closes: #13302

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

src/proto/vim9class.pro

@@ -10,11 +10,8 @@ ufunc_T *find_class_func(char_u **arg);
 int class_member_idx(class_T *cl, char_u *name, size_t namelen);
 ocmember_T *class_member_lookup(class_T *cl, char_u *name, size_t namelen, int *idx);
 int class_method_idx(class_T *cl, char_u *name, size_t namelen);
-ufunc_T *class_method_lookup(class_T *cl, char_u *name, size_t namelen, int *idx);
-int object_member_idx(class_T *cl, char_u *name, size_t namelen);
 ocmember_T *object_member_lookup(class_T *cl, char_u *name, size_t namelen, int *idx);
 int object_method_idx(class_T *cl, char_u *name, size_t namelen);
-ufunc_T *object_method_lookup(class_T *cl, char_u *name, size_t namelen, int *idx);
 ocmember_T *member_lookup(class_T *cl, vartype_T v_type, char_u *name, size_t namelen, int *idx);
 void emsg_var_cl_define(char *msg, char_u *name, size_t len, class_T *cl);
 ufunc_T *method_lookup(class_T *cl, vartype_T v_type, char_u *name, size_t namelen, int *idx);
@@ -26,7 +23,6 @@ void class_unref(class_T *cl);
 int class_free_nonref(int copyID);
 int set_ref_in_classes(int copyID);
 void object_created(object_T *obj);
-void object_cleared(object_T *obj);
 int object_free_nonref(int copyID);
 void method_not_found_msg(class_T *cl, vartype_T v_type, char_u *name, size_t len);
 void member_not_found_msg(class_T *cl, vartype_T v_type, char_u *name, size_t len);

src/testdir/test_vim9_class.vim

@@ -975,6 +975,28 @@ def Test_class_new_with_object_member()
     Check()
   END
   v9.CheckSourceSuccess(lines)
+
+  # Try using "this." argument in a class method
+  lines =<< trim END
+    vim9script
+    class A
+      this.val = 10
+      static def Foo(this.val: number)
+      enddef
+    endclass
+  END
+  v9.CheckSourceFailure(lines, 'E1390: Cannot use an object variable "this.val" except with the "new" method', 4)
+
+  # Try using "this." argument in an object method
+  lines =<< trim END
+    vim9script
+    class A
+      this.val = 10
+      def Foo(this.val: number)
+      enddef
+    endclass
+  END
+  v9.CheckSourceFailure(lines, 'E1390: Cannot use an object variable "this.val" except with the "new" method', 4)
 enddef
 
 def Test_class_object_member_inits()
@@ -1722,7 +1744,7 @@ def Test_class_member()
     var a = A.new()
     var v = a.bar
   END
-  v9.CheckSourceFailure(lines, 'E1326: Variable not found on object "A": bar', 5)
+  v9.CheckSourceFailure(lines, 'E1337: Class variable "bar" not found in class "A"', 5)
 enddef
 
 " These messages should show the defining class of the variable (base class),
@@ -4255,7 +4277,7 @@ def Test_private_object_method()
     var a = A.new()
     a._Foo()
   END
-  v9.CheckSourceFailure(lines, 'E1366: Cannot access private method: _Foo()', 9)
+  v9.CheckSourceFailure(lines, 'E1366: Cannot access private method: _Foo', 9)
 
   # Try calling a private method using an object (from a def function)
   lines =<< trim END
@@ -4468,7 +4490,7 @@ def Test_private_object_method()
     var c = C.new()
     assert_equal(1234, c._Foo())
   END
-  v9.CheckSourceFailure(lines, 'E1366: Cannot access private method: _Foo()', 16)
+  v9.CheckSourceFailure(lines, 'E1366: Cannot access private method: _Foo', 16)
 
   # Using "_" prefix in a method name should fail outside of a class
   lines =<< trim END
@@ -4494,7 +4516,7 @@ def Test_private_class_method()
     endclass
     A._Foo()
   END
-  v9.CheckSourceFailure(lines, 'E1366: Cannot access private method: _Foo()', 8)
+  v9.CheckSourceFailure(lines, 'E1366: Cannot access private method: _Foo', 8)
 
   # Try calling a class private method (from a def function)
   lines =<< trim END
@@ -5122,7 +5144,7 @@ def Test_class_variable_access_using_object()
     var a = A.new()
     echo a.svar2
   END
-  v9.CheckSourceFailure(lines, 'E1375: Class variable "svar2" accessible only using class "A"', 8)
+  v9.CheckSourceFailure(lines, 'E1337: Class variable "svar2" not found in class "A"', 8)
 
   # Cannot write to a class variable using an object in script context
   lines =<< trim END
@@ -5597,7 +5619,7 @@ def Test_class_variable()
     var a = A.new()
     var i = a.val
   END
-  v9.CheckSourceFailure(lines, 'E1375: Class variable "val" accessible only using class "A"', 7)
+  v9.CheckSourceFailure(lines, 'E1337: Class variable "val" not found in class "A"', 7)
 
   # Modifying a class variable using an object at function level
   lines =<< trim END
@@ -5969,6 +5991,18 @@ def Test_extend_interface()
   END
   v9.CheckSourceSuccess(lines)
 
+  # extending empty interface
+  lines =<< trim END
+    vim9script
+    interface A
+    endinterface
+    interface B extends A
+    endinterface
+    class C implements B
+    endclass
+  END
+  v9.CheckSourceSuccess(lines)
+
   lines =<< trim END
     vim9script
     interface A
@@ -6567,6 +6601,17 @@ def Test_reserved_varname()
       o.F()
     END
     v9.CheckSourceFailure(lines, $'E1034: Cannot use reserved name {kword}', 3)
+
+    # class variable name
+    if kword != 'this'
+      lines =<< trim eval END
+        vim9script
+        class C
+          public static {kword}: list<number> = [1, 2, 3]
+        endclass
+      END
+      v9.CheckSourceFailure(lines, $'E1034: Cannot use reserved name {kword}', 3)
+    endif
   endfor
 enddef
 

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2002,
 /**/
     2001,
 /**/