patch 9.0.1138: crash when expecting varargs but it is something else

Problem:    Crash when expecting varargs but it is something else.
Solution:   Only use the member when the type is a list. (closes #11774)

src/testdir/test_vim9_func.vim

@@ -1869,6 +1869,20 @@ def Test_call_varargs_only()
   v9.CheckDefFailure(['g:MyVarargsOnly("one", 2)'], 'E1013: Argument 2: type mismatch, expected string but got number')
 enddef
 
+def Test_varargs_mismatch()
+  var lines =<< trim END
+      vim9script
+
+      def Map(Fn: func(...any): number): number
+        return Fn('12')
+      enddef
+
+      var res = Map((v) => str2nr(v))
+      assert_equal(12, res)
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
 def Test_using_var_as_arg()
   var lines =<< trim END
       def Func(x: number)

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1138,
 /**/
     1137,
 /**/

src/vim9instr.c

@@ -1841,7 +1841,13 @@ check_func_args_from_type(
 		type_T	*expected;
 
 		if (varargs && i >= type->tt_argcount - 1)
-		    expected = type->tt_args[type->tt_argcount - 1]->tt_member;
+		{
+		    expected = type->tt_args[type->tt_argcount - 1];
+		    if (expected != NULL && expected->tt_type == VAR_LIST)
+			expected = expected->tt_member;
+		    if (expected == NULL)
+			expected = &t_any;
+		}
 		else if (i >= type->tt_min_argcount
 					     && actual->tt_type == VAR_SPECIAL)
 		    expected = &t_any;

src/vim9type.c

@@ -932,8 +932,10 @@ check_argument_types(
 	if (varargs && i >= type->tt_argcount - 1)
 	{
 	    expected = type->tt_args[type->tt_argcount - 1];
-	    if (expected != NULL)
+	    if (expected != NULL && expected->tt_type == VAR_LIST)
 		expected = expected->tt_member;
+	    if (expected == NULL)
+		expected = &t_any;
 	}
 	else
 	    expected = type->tt_args[i];