patch 8.2.4216: Vim9: cannot use a function from an autoload import directly

Problem:    Vim9: cannot use a function from an autoload import directly.
Solution:   Add the AUTOLOAD instruction to figure out at runtime.
            (closes #9620)
diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index 3a7642f..8731052 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -1,6 +1,7 @@
 " Test the :disassemble command, and compilation as a side effect
 
 source check.vim
+source vim9.vim
 
 func NotCompiled()
   echo "not"
@@ -286,21 +287,35 @@
 enddef
 
 def Test_disassemble_push()
-  var res = execute('disass s:ScriptFuncPush')
-  assert_match('<SNR>\d*_ScriptFuncPush.*' ..
-        'localbool = true.*' ..
-        ' PUSH true.*' ..
-        'localspec = v:none.*' ..
-        ' PUSH v:none.*' ..
-        'localblob = 0z1234.*' ..
-        ' PUSHBLOB 0z1234.*',
-        res)
-  if has('float')
-    assert_match('<SNR>\d*_ScriptFuncPush.*' ..
-          'localfloat = 1.234.*' ..
-          ' PUSHF 1.234.*',
-          res)
-  endif
+  mkdir('Xdir/autoload', 'p')
+  var save_rtp = &rtp
+  exe 'set rtp^=' .. getcwd() .. '/Xdir'
+
+  var lines =<< trim END
+      vim9script
+  END
+  writefile(lines, 'Xdir/autoload/autoscript.vim')
+
+  lines =<< trim END
+      vim9script
+      import autoload 'autoscript.vim'
+
+      def s:AutoloadFunc()
+        &operatorfunc = autoscript.Opfunc
+      enddef
+
+      var res = execute('disass s:AutoloadFunc')
+      assert_match('<SNR>\d*_AutoloadFunc.*' ..
+            '&operatorfunc = autoscript.Opfunc\_s*' ..
+            '0 AUTOLOAD autoscript#Opfunc\_s*' ..
+            '1 STOREFUNCOPT &operatorfunc\_s*' ..
+            '2 RETURN void',
+            res)
+  END
+  CheckScriptSuccess(lines)
+
+  delete('Xdir', 'rf')
+  &rtp = save_rtp
 enddef
 
 def s:ScriptFuncStore()
diff --git a/src/testdir/test_vim9_import.vim b/src/testdir/test_vim9_import.vim
index 506b0ee..7878788 100644
--- a/src/testdir/test_vim9_import.vim
+++ b/src/testdir/test_vim9_import.vim
@@ -703,6 +703,41 @@
   set opfunc=
   bwipe!
   delete('Xdir', 'rf')
+  nunmap <F3>
+  &rtp = save_rtp
+enddef
+
+def Test_set_opfunc_to_autoload_func_directly()
+  mkdir('Xdir/autoload', 'p')
+  var save_rtp = &rtp
+  exe 'set rtp^=' .. getcwd() .. '/Xdir'
+
+  var lines =<< trim END
+      vim9script
+      export def Opfunc(..._)
+        g:opfunc_called = 'yes'
+      enddef
+  END
+  writefile(lines, 'Xdir/autoload/opfunc.vim')
+
+  new
+  lines =<< trim END
+      vim9script
+      import autoload 'opfunc.vim'
+      nnoremap <expr> <F3> TheFunc()
+      def TheFunc(): string
+        &operatorfunc = opfunc.Opfunc
+        return 'g@'
+      enddef
+      feedkeys("\<F3>l", 'xt')
+      assert_equal('yes', g:opfunc_called)
+  END
+  CheckScriptSuccess(lines)
+
+  set opfunc=
+  bwipe!
+  delete('Xdir', 'rf')
+  nunmap <F3>
   &rtp = save_rtp
 enddef