patch 8.2.0467: Vim9: some errors are not tested

Problem:    Vim9: some errors are not tested
Solution:   Add more tests.  Fix that Vim9 script flag is not reset.
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index d67c2d5..c9d5024 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -812,12 +812,25 @@
   call CheckDefExecFailure("echo s:doesnt_exist", 'E121:')
   call CheckDefExecFailure("echo g:doesnt_exist", 'E121:')
 
+  call CheckDefFailure("echo a:somevar", 'E1075:')
+  call CheckDefFailure("echo l:somevar", 'E1075:')
+  call CheckDefFailure("echo x:somevar", 'E1075:')
+
+  " TODO
+  call CheckDefFailure("echo b:somevar", 'not supported yet')
+  call CheckDefFailure("echo w:somevar", 'not supported yet')
+  call CheckDefFailure("echo t:somevar", 'not supported yet')
+
   call CheckDefExecFailure("let x = +g:astring", 'E1030:')
   call CheckDefExecFailure("let x = +g:ablob", 'E974:')
   call CheckDefExecFailure("let x = +g:alist", 'E745:')
   call CheckDefExecFailure("let x = +g:adict", 'E728:')
 
   call CheckDefFailureMult(["let x = ''", "let y = x.memb"], 'E715:')
+
+  call CheckDefExecFailure("[1, 2->len()", 'E492:')
+  call CheckDefExecFailure("#{a: 1->len()", 'E488:')
+  call CheckDefExecFailure("{'a': 1->len()", 'E492:')
 endfunc
 
 let g:Funcrefs = [function('add')]
@@ -878,4 +891,8 @@
   call CheckDefFailure("v:nosuch += 3", 'E1001:')
   call CheckDefFailure("let v:version = 3", 'E1064:')
   call CheckDefFailure("let asdf = v:nosuch", 'E1001:')
+
+  call CheckDefFailure("echo len('asdf'", 'E110:')
+  call CheckDefFailure("echo Func0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789()", 'E1011:')
+  call CheckDefFailure("echo doesnotexist()", 'E117:')
 endfunc