patch 9.1.1274: Vim9: no support for object<type> as variable type

Problem:  Vim9: no support for object<type> as variable type
Solution: add support for object<type> (Yegappan Lakshmanan)

closes: #17041

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_vim9_class.vim b/src/testdir/test_vim9_class.vim
index c6d93b2..4b6cb81 100644
--- a/src/testdir/test_vim9_class.vim
+++ b/src/testdir/test_vim9_class.vim
@@ -12808,4 +12808,178 @@
   v9.CheckSourceSuccess(lines)
 enddef
 
+" Test for using the type() and typename() functions with a variable of type
+" object
+def Test_type_typename_funcs_with_object_variable()
+  var lines =<< trim END
+    vim9script
+
+    class A
+    endclass
+
+    class B
+    endclass
+
+    var o1: object<any>
+    assert_equal([13, 'object<any>'], [type(o1), typename(o1)])
+
+    var o2: object<A>
+    assert_equal([13, 'object<any>'], [type(o2), typename(o2)])
+
+    var o3: A
+    assert_equal([13, 'object<any>'], [type(o3), typename(o3)])
+
+    var o4 = A.new()
+    assert_equal([13, 'object<A>'], [type(o4), typename(o4)])
+
+    var l = [A.new(), B.new()]
+    assert_equal([13, 'object<B>'], [type(l[1]), typename(l[1])])
+
+    var d = {o_a: A.new(), o_b: B.new()}
+    assert_equal([13, 'object<B>'], [type(d.o_b), typename(d.o_b)])
+  END
+  v9.CheckSourceSuccess(lines)
+enddef
+
+" Test for object<any> type
+def Test_object_any_type()
+  # assigning different objects to variable of type object<any>
+  var lines =<< trim END
+    vim9script
+    class A
+    endclass
+    class B
+    endclass
+    var x: object<any>
+    x = A.new()
+    assert_true(instanceof(x, A))
+    x = B.new()
+    assert_true(instanceof(x, B))
+    x = null_object
+    assert_true(instanceof(x, null_class))
+  END
+  v9.CheckSourceSuccess(lines)
+
+  # Use a list of object<any> variable
+  lines =<< trim END
+    vim9script
+    class A
+    endclass
+    class B
+    endclass
+    var l: list<object<any>>
+    l->add(A.new())
+    l->add(B.new())
+    assert_true(instanceof(l[0], A))
+    assert_true(instanceof(l[1], B))
+  END
+  v9.CheckSourceSuccess(lines)
+
+  # Using object<any> as a function argument type and the return type
+  lines =<< trim END
+    vim9script
+    class A
+    endclass
+    class B
+    endclass
+    def Fn(x: object<any>): object<any>
+      return x
+    enddef
+    assert_true(instanceof(Fn(A.new()), A))
+    assert_true(instanceof(Fn(B.new()), B))
+  END
+
+  # Try assigning a different type of value to a object<any> variable
+  lines =<< trim END
+    var x: object<any> = []
+  END
+  v9.CheckSourceDefAndScriptFailure(lines, ['E1012: Type mismatch; expected object<any> but got list<any>', 'E1012: Type mismatch; expected object<any> but got list<any>'])
+
+  # Try assigning a different type of value to a object<any> variable
+  lines =<< trim END
+    var x: object<any>
+    x = 0z10
+  END
+  v9.CheckSourceDefAndScriptFailure(lines, ['E1012: Type mismatch; expected object<any> but got blob', 'E1012: Type mismatch; expected object<any> but got blob'])
+
+  # Try adding a different type of value to a list<object<any>> variable
+  lines =<< trim END
+    var x: list<object<any>>
+    x->add({})
+  END
+  v9.CheckSourceDefAndScriptFailure(lines, ['E1012: Type mismatch; expected object<any> but got dict<any>', 'E1012: Type mismatch; expected object<any> but got dict<any>'])
+
+  # Try adding a different type of value to a dict<object<any>> variable
+  lines =<< trim END
+    var x: dict<object<any>>
+    x['a'] = {}
+  END
+  v9.CheckSourceDefAndScriptFailure(lines, ['E1012: Type mismatch; expected object<any> but got dict<any>', 'E1012: Type mismatch; expected object<any> but got dict<any>'])
+enddef
+
+" Test for object<{class}> type
+def Test_object_of_class_type()
+  var lines =<< trim END
+    vim9script
+    class A
+    endclass
+    var x: object<A>
+    x = A.new()
+    assert_true(instanceof(x, A))
+    var y: object<A> = A.new()
+    assert_true(instanceof(y, A))
+  END
+  v9.CheckSourceSuccess(lines)
+
+  lines =<< trim END
+    vim9script
+    class A
+    endclass
+    class B
+    endclass
+    var x: object<A>
+    x = B.new()
+  END
+  v9.CheckSourceFailure(lines, 'E1012: Type mismatch; expected object<A> but got object<B>')
+
+  lines =<< trim END
+    vim9script
+    class A
+    endclass
+    class B
+    endclass
+    def Fn(x: object<A>): object<B>
+      return B.new()
+    enddef
+    assert_true(instanceof(Fn(A.new()), B))
+  END
+  v9.CheckSourceSuccess(lines)
+
+  lines =<< trim END
+    var x: object
+  END
+  v9.CheckSourceDefAndScriptFailure(lines, ['E1008: Missing <type> after object', 'E1008: Missing <type> after object'])
+
+  lines =<< trim END
+    var x: object <any>
+  END
+  v9.CheckSourceDefAndScriptFailure(lines, ['E1068: No white space allowed before ''<'':  <any>', 'E1068: No white space allowed before ''<'':  <any>'])
+
+  lines =<< trim END
+    var x: object<any
+  END
+  v9.CheckSourceDefAndScriptFailure(lines, ['E1009: Missing > after type: <any', 'E1009: Missing > after type: <any'])
+
+  lines =<< trim END
+    var x: object<any,any>
+  END
+  v9.CheckSourceDefFailure(lines, 'E1009: Missing > after type: <any,any>')
+
+  lines =<< trim END
+    vim9script
+    var x: object<any,any>
+  END
+  v9.CheckSourceFailure(lines, 'E488: Trailing characters: ,any>')
+enddef
+
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker
diff --git a/src/version.c b/src/version.c
index e00e007..42576d1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1274,
+/**/
     1273,
 /**/
     1272,
diff --git a/src/vim9class.c b/src/vim9class.c
index 5249f40..560c5ae 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -4132,7 +4132,12 @@
 	return;
 
     if (object_tv->vval.v_object == NULL)
+    {
+	if (classinfo_tv->vval.v_class == NULL)
+	    // consider null_object as an instance of null_class
+	    rettv->vval.v_number = VVAL_TRUE;
 	return;
+    }
 
     for (; classinfo_tv->v_type != VAR_UNKNOWN; ++classinfo_tv)
     {
diff --git a/src/vim9type.c b/src/vim9type.c
index 2f85095..a3881c9 100644
--- a/src/vim9type.c
+++ b/src/vim9type.c
@@ -1785,6 +1785,63 @@
 }
 
 /*
+ * Parse a "object" type at "*arg" and advance over it.
+ * When "give_error" is TRUE give error messages, otherwise be quiet.
+ * Return NULL for failure.
+ */
+    static type_T *
+parse_type_object(char_u **arg, garray_T *type_gap, int give_error)
+{
+    char_u	*arg_start = *arg;
+    type_T	*object_type;
+    int		prev_called_emsg = called_emsg;
+
+    // object<X> or object<any>
+    if (**arg != '<')
+    {
+	if (give_error)
+	{
+	    if (*skipwhite(*arg) == '<')
+		semsg(_(e_no_white_space_allowed_before_str_str), "<", *arg);
+	    else
+		semsg(_(e_missing_type_after_str), "object");
+	}
+
+	// only "object" is specified
+	return NULL;
+    }
+
+    // skip spaces following "object<"
+    *arg = skipwhite(*arg + 1);
+
+    object_type = parse_type(arg, type_gap, give_error);
+    if (object_type == NULL)
+	return NULL;
+
+    *arg = skipwhite(*arg);
+    if (**arg != '>' && called_emsg == prev_called_emsg)
+    {
+	if (give_error)
+	    semsg(_(e_missing_gt_after_type_str), arg_start);
+	return NULL;
+    }
+    ++*arg;
+
+    if (object_type->tt_type == VAR_ANY)
+	return &t_object_any;
+
+    if (object_type->tt_type != VAR_OBJECT)
+    {
+	// specified type is not a class
+	if (give_error)
+	    semsg(_(e_class_name_not_found_str), arg_start);
+	return NULL;
+    }
+
+    return object_type;
+}
+
+/*
  * Parse a user defined type at "*arg" and advance over it.
  * It can be a class or an interface or a typealias name, possibly imported.
  * Return NULL if a type is not found.
@@ -1932,6 +1989,13 @@
 		return &t_number;
 	    }
 	    break;
+	case 'o':
+	    if (len == 6 && STRNCMP(*arg, "object", len) == 0)
+	    {
+		*arg += len;
+		return parse_type_object(arg, type_gap, give_error);
+	    }
+	    break;
 	case 's':
 	    if (len == 6 && STRNCMP(*arg, "string", len) == 0)
 	    {