patch 8.2.3007: Vim9: test for void value fails

Problem:    Vim9: test for void value fails.
Solution:   Adjust expected error.  Do not make a copy of void.

Author: brammool

src/testdir/test_functions.vim

@@ -86,13 +86,13 @@ func Test_empty()
 endfunc
 
 func Test_test_void()
-  call assert_fails('echo 1 == test_void()', 'E685:')
+  call assert_fails('echo 1 == test_void()', 'E1031:')
   if has('float')
-    call assert_fails('echo 1.0 == test_void()', 'E685:')
+    call assert_fails('echo 1.0 == test_void()', 'E1031:')
   endif
   call assert_fails('let x = json_encode(test_void())', 'E685:')
   call assert_fails('let x = copy(test_void())', 'E685:')
-  call assert_fails('let x = copy([test_void()])', 'E685:')
+  call assert_fails('let x = copy([test_void()])', 'E1031:')
 endfunc
 
 func Test_len()

src/typval.c

@@ -591,7 +591,6 @@ copy_tv(typval_T *from, typval_T *to)
 	case VAR_NUMBER:
 	case VAR_BOOL:
 	case VAR_SPECIAL:
-	case VAR_VOID:
 	    to->vval.v_number = from->vval.v_number;
 	    break;
 	case VAR_FLOAT:
@@ -664,6 +663,9 @@ copy_tv(typval_T *from, typval_T *to)
 		++to->vval.v_dict->dv_refcount;
 	    }
 	    break;
+	case VAR_VOID:
+	    emsg(_(e_cannot_use_void_value));
+	    break;
 	case VAR_UNKNOWN:
 	case VAR_ANY:
 	    internal_error_no_abort("copy_tv(UNKNOWN)");

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3007,
 /**/
     3006,
 /**/