patch 8.2.2188: Vim9: crash when calling global function from :def function

Problem:    Vim9: crash when calling global function from :def function.
Solution:   Set the outer context.  Define the partial for the context on the
            original function. Use a refcount to keep track of which ufunc is
            using a dfunc. (closes #7525)

src/eval.c

@@ -654,11 +654,28 @@ call_func_retnr(
     return retval;
 }
 
+/*
+ * Call Vim script function like call_func_retnr() and drop the result.
+ * Returns FAIL when calling the function fails.
+ */
+    int
+call_func_noret(
+    char_u      *func,
+    int		argc,
+    typval_T	*argv)
+{
+    typval_T	rettv;
+
+    if (call_vim_function(func, argc, argv, &rettv) == FAIL)
+	return FAIL;
+    clear_tv(&rettv);
+    return OK;
+}
+
 /*
  * Call Vim script function "func" and return the result as a string.
+ * Uses "argv" and "argc" as call_func_retnr().
  * Returns NULL when calling the function fails.
- * Uses argv[0] to argv[argc - 1] for the function arguments. argv[argc] should
- * have type VAR_UNKNOWN.
  */
     void *
 call_func_retstr(
@@ -679,8 +696,7 @@ call_func_retstr(
 
 /*
  * Call Vim script function "func" and return the result as a List.
- * Uses argv[0] to argv[argc - 1] for the function arguments. argv[argc] should
- * have type VAR_UNKNOWN.
+ * Uses "argv" and "argc" as call_func_retnr().
  * Returns NULL when there is something wrong.
  */
     void *

src/ops.c

@@ -3299,7 +3299,7 @@ op_function(oparg_T *oap UNUSED)
 	// function.
 	virtual_op = MAYBE;
 
-	(void)call_func_retnr(p_opfunc, 1, argv);
+	(void)call_func_noret(p_opfunc, 1, argv);
 
 	virtual_op = save_virtual_op;
 	if (cmdmod.cmod_flags & CMOD_LOCKMARKS)

src/proto/eval.pro

@@ -18,6 +18,7 @@ varnumber_T eval_to_number(char_u *expr);
 typval_T *eval_expr(char_u *arg, exarg_T *eap);
 int call_vim_function(char_u *func, int argc, typval_T *argv, typval_T *rettv);
 varnumber_T call_func_retnr(char_u *func, int argc, typval_T *argv);
+int call_func_noret(char_u *func, int argc, typval_T *argv);
 void *call_func_retstr(char_u *func, int argc, typval_T *argv);
 void *call_func_retlist(char_u *func, int argc, typval_T *argv);
 int eval_foldexpr(char_u *arg, int *cp);

src/proto/userfunc.pro

@@ -13,7 +13,7 @@ ufunc_T *find_func_even_dead(char_u *name, int is_global, cctx_T *cctx);
 ufunc_T *find_func(char_u *name, int is_global, cctx_T *cctx);
 int func_is_global(ufunc_T *ufunc);
 int func_name_refcount(char_u *name);
-ufunc_T *copy_func(char_u *lambda, char_u *global);
+int copy_func(char_u *lambda, char_u *global, ectx_T *ectx);
 int funcdepth_increment(void);
 void funcdepth_decrement(void);
 int funcdepth_get(void);

src/proto/vim9compile.pro

@@ -18,7 +18,7 @@ int check_vim9_unlet(char_u *name);
 int compile_def_function(ufunc_T *ufunc, int set_return_type, cctx_T *outer_cctx);
 void set_function_type(ufunc_T *ufunc);
 void delete_instr(isn_T *isn);
-void clear_def_function(ufunc_T *ufunc);
 void unlink_def_function(ufunc_T *ufunc);
+void link_def_function(ufunc_T *ufunc);
 void free_def_functions(void);
 /* vim: set ft=c : */

src/proto/vim9execute.pro

@@ -1,6 +1,7 @@
 /* vim9execute.c */
 void to_string_error(vartype_T vartype);
 void funcstack_check_refcount(funcstack_T *funcstack);
+int fill_partial_and_closure(partial_T *pt, ufunc_T *ufunc, ectx_T *ectx);
 int call_def_function(ufunc_T *ufunc, int argc_arg, typval_T *argv, partial_T *partial, typval_T *rettv);
 void ex_disassemble(exarg_T *eap);
 int tv2bool(typval_T *tv);

src/quickfix.c

@@ -6513,7 +6513,7 @@ wipe_dummy_buffer(buf_T *buf, char_u *dirname_start)
 	enter_cleanup(&cs);
 #endif
 
-	wipe_buffer(buf, FALSE);
+	wipe_buffer(buf, TRUE);
 
 #if defined(FEAT_EVAL)
 	// Restore the error/interrupt/exception state if not discarded by a

src/structs.h

@@ -1363,6 +1363,7 @@ typedef struct jsonq_S jsonq_T;
 typedef struct cbq_S cbq_T;
 typedef struct channel_S channel_T;
 typedef struct cctx_S cctx_T;
+typedef struct ectx_S ectx_T;
 
 typedef enum
 {

src/testdir/test_autocmd.vim

@@ -132,19 +132,19 @@ func Test_bufunload()
     autocmd BufWipeout * call add(s:li, "bufwipeout")
   augroup END
 
-  let s:li=[]
+  let s:li = []
   new
   setlocal bufhidden=
   bunload
   call assert_equal(["bufunload", "bufdelete"], s:li)
 
-  let s:li=[]
+  let s:li = []
   new
   setlocal bufhidden=delete
   bunload
   call assert_equal(["bufunload", "bufdelete"], s:li)
 
-  let s:li=[]
+  let s:li = []
   new
   setlocal bufhidden=unload
   bwipeout
@@ -221,6 +221,29 @@ func Test_autocmd_bufunload_avoiding_SEGV_02()
   bwipe! a.txt
 endfunc
 
+func Test_autocmd_dummy_wipeout()
+  " prepare files
+  call writefile([''], 'Xdummywipetest1.txt')
+  call writefile([''], 'Xdummywipetest2.txt')
+  augroup test_bufunload_group
+    autocmd!
+    autocmd BufUnload * call add(s:li, "bufunload")
+    autocmd BufDelete * call add(s:li, "bufdelete")
+    autocmd BufWipeout * call add(s:li, "bufwipeout")
+  augroup END
+
+  let s:li = []
+  split Xdummywipetest1.txt
+  silent! vimgrep /notmatched/ Xdummywipetest*
+  call assert_equal(["bufunload", "bufwipeout"], s:li)
+
+  bwipeout
+  call delete('Xdummywipetest1.txt')
+  call delete('Xdummywipetest2.txt')
+  au! test_bufunload_group
+  augroup! test_bufunload_group
+endfunc
+
 func Test_win_tab_autocmd()
   let g:record = []
 
@@ -454,7 +477,7 @@ func Test_autocmd_bufwipe_in_SessLoadPost()
   let content =<< trim [CODE]
     call test_override('ui_delay', 10)
     set nocp noswapfile
-    let v:swapchoice="e"
+    let v:swapchoice = "e"
     augroup test_autocmd_sessionload
     autocmd!
     autocmd SessionLoadPost * exe bufnr("Xsomething") . "bw!"
@@ -542,43 +565,43 @@ func Test_OptionSet()
   au OptionSet * :call s:AutoCommandOptionSet(expand("<amatch>"))
 
   " 1: Setting number option"
-  let g:options=[['number', 0, 0, 0, 1, 'global', 'set']]
+  let g:options = [['number', 0, 0, 0, 1, 'global', 'set']]
   set nu
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 2: Setting local number option"
-  let g:options=[['number', 1, 1, '', 0, 'local', 'setlocal']]
+  let g:options = [['number', 1, 1, '', 0, 'local', 'setlocal']]
   setlocal nonu
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 3: Setting global number option"
-  let g:options=[['number', 1, '', 1, 0, 'global', 'setglobal']]
+  let g:options = [['number', 1, '', 1, 0, 'global', 'setglobal']]
   setglobal nonu
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 4: Setting local autoindent option"
-  let g:options=[['autoindent', 0, 0, '', 1, 'local', 'setlocal']]
+  let g:options = [['autoindent', 0, 0, '', 1, 'local', 'setlocal']]
   setlocal ai
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 5: Setting global autoindent option"
-  let g:options=[['autoindent', 0, '', 0, 1, 'global', 'setglobal']]
+  let g:options = [['autoindent', 0, '', 0, 1, 'global', 'setglobal']]
   setglobal ai
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 6: Setting global autoindent option"
-  let g:options=[['autoindent', 1, 1, 1, 0, 'global', 'set']]
+  let g:options = [['autoindent', 1, 1, 1, 0, 'global', 'set']]
   set ai!
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 6a: Setting global autoindent option"
-  let g:options=[['autoindent', 1, 1, 0, 0, 'global', 'set']]
+  let g:options = [['autoindent', 1, 1, 0, 0, 'global', 'set']]
   noa setlocal ai
   noa setglobal noai
   set ai!
@@ -587,55 +610,55 @@ func Test_OptionSet()
 
   " Should not print anything, use :noa
   " 7: don't trigger OptionSet"
-  let g:options=[['invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid']]
+  let g:options = [['invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid']]
   noa set nonu
   call assert_equal([['invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid']], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 8: Setting several global list and number option"
-  let g:options=[['list', 0, 0, 0, 1, 'global', 'set'], ['number', 0, 0, 0, 1, 'global', 'set']]
+  let g:options = [['list', 0, 0, 0, 1, 'global', 'set'], ['number', 0, 0, 0, 1, 'global', 'set']]
   set list nu
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 9: don't trigger OptionSet"
-  let g:options=[['invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid'], ['invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid']]
+  let g:options = [['invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid'], ['invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid']]
   noa set nolist nonu
   call assert_equal([['invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid'], ['invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid', 'invalid']], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 10: Setting global acd"
-  let g:options=[['autochdir', 0, 0, '', 1, 'local', 'setlocal']]
+  let g:options = [['autochdir', 0, 0, '', 1, 'local', 'setlocal']]
   setlocal acd
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 11: Setting global autoread (also sets local value)"
-  let g:options=[['autoread', 0, 0, 0, 1, 'global', 'set']]
+  let g:options = [['autoread', 0, 0, 0, 1, 'global', 'set']]
   set ar
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 12: Setting local autoread"
-  let g:options=[['autoread', 1, 1, '', 1, 'local', 'setlocal']]
+  let g:options = [['autoread', 1, 1, '', 1, 'local', 'setlocal']]
   setlocal ar
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 13: Setting global autoread"
-  let g:options=[['autoread', 1, '', 1, 0, 'global', 'setglobal']]
+  let g:options = [['autoread', 1, '', 1, 0, 'global', 'setglobal']]
   setglobal invar
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 14: Setting option backspace through :let"
-  let g:options=[['backspace', '', '', '', 'eol,indent,start', 'global', 'set']]
-  let &bs="eol,indent,start"
+  let g:options = [['backspace', '', '', '', 'eol,indent,start', 'global', 'set']]
+  let &bs = "eol,indent,start"
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 15: Setting option backspace through setbufvar()"
-  let g:options=[['backup', 0, 0, '', 1, 'local', 'setlocal']]
+  let g:options = [['backup', 0, 0, '', 1, 'local', 'setlocal']]
   " try twice, first time, shouldn't trigger because option name is invalid,
   " second time, it should trigger
   let bnum = bufnr('%')
@@ -646,13 +669,13 @@ func Test_OptionSet()
   call assert_equal(g:opt[0], g:opt[1])
 
   " 16: Setting number option using setwinvar"
-  let g:options=[['number', 0, 0, '', 1, 'local', 'setlocal']]
+  let g:options = [['number', 0, 0, '', 1, 'local', 'setlocal']]
   call setwinvar(0, '&number', 1)
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 17: Setting key option, shouldn't trigger"
-  let g:options=[['key', 'invalid', 'invalid1', 'invalid2', 'invalid3', 'invalid4', 'invalid5']]
+  let g:options = [['key', 'invalid', 'invalid1', 'invalid2', 'invalid3', 'invalid4', 'invalid5']]
   setlocal key=blah
   setlocal key=
   call assert_equal([['key', 'invalid', 'invalid1', 'invalid2', 'invalid3', 'invalid4', 'invalid5']], g:options)
@@ -661,19 +684,19 @@ func Test_OptionSet()
 
   " 18a: Setting string global option"
   let oldval = &backupext
-  let g:options=[['backupext', oldval, oldval, oldval, 'foo', 'global', 'set']]
+  let g:options = [['backupext', oldval, oldval, oldval, 'foo', 'global', 'set']]
   set backupext=foo
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 18b: Resetting string global option"
-  let g:options=[['backupext', 'foo', 'foo', 'foo', oldval, 'global', 'set']]
+  let g:options = [['backupext', 'foo', 'foo', 'foo', oldval, 'global', 'set']]
   set backupext&
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 18c: Setting global string global option"
-  let g:options=[['backupext', oldval, '', oldval, 'bar', 'global', 'setglobal']]
+  let g:options = [['backupext', oldval, '', oldval, 'bar', 'global', 'setglobal']]
   setglobal backupext=bar
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -682,7 +705,7 @@ func Test_OptionSet()
   " As this is a global option this sets the global value even though
   " :setlocal is used!
   noa set backupext& " Reset global and local value (without triggering autocmd)
-  let g:options=[['backupext', oldval, oldval, '', 'baz', 'local', 'setlocal']]
+  let g:options = [['backupext', oldval, oldval, '', 'baz', 'local', 'setlocal']]
   setlocal backupext=baz
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -690,7 +713,7 @@ func Test_OptionSet()
   " 18e: Setting again string global option"
   noa setglobal backupext=ext_global " Reset global and local value (without triggering autocmd)
   noa setlocal backupext=ext_local " Sets the global(!) value!
-  let g:options=[['backupext', 'ext_local', 'ext_local', 'ext_local', 'fuu', 'global', 'set']]
+  let g:options = [['backupext', 'ext_local', 'ext_local', 'ext_local', 'fuu', 'global', 'set']]
   set backupext=fuu
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -698,25 +721,25 @@ func Test_OptionSet()
 
   " 19a: Setting string local-global (to buffer) option"
   let oldval = &tags
-  let g:options=[['tags', oldval, oldval, oldval, 'tagpath', 'global', 'set']]
+  let g:options = [['tags', oldval, oldval, oldval, 'tagpath', 'global', 'set']]
   set tags=tagpath
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 19b: Resetting string local-global (to buffer) option"
-  let g:options=[['tags', 'tagpath', 'tagpath', 'tagpath', oldval, 'global', 'set']]
+  let g:options = [['tags', 'tagpath', 'tagpath', 'tagpath', oldval, 'global', 'set']]
   set tags&
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 19c: Setting global string local-global (to buffer) option "
-  let g:options=[['tags', oldval, '', oldval, 'tagpath1', 'global', 'setglobal']]
+  let g:options = [['tags', oldval, '', oldval, 'tagpath1', 'global', 'setglobal']]
   setglobal tags=tagpath1
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 19d: Setting local string local-global (to buffer) option"
-  let g:options=[['tags', 'tagpath1', 'tagpath1', '', 'tagpath2', 'local', 'setlocal']]
+  let g:options = [['tags', 'tagpath1', 'tagpath1', '', 'tagpath2', 'local', 'setlocal']]
   setlocal tags=tagpath2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -726,7 +749,7 @@ func Test_OptionSet()
   " but the old local value for all other kinds of options.
   noa setglobal tags=tag_global " Reset global and local value (without triggering autocmd)
   noa setlocal tags=tag_local
-  let g:options=[['tags', 'tag_global', 'tag_local', 'tag_global', 'tagpath', 'global', 'set']]
+  let g:options = [['tags', 'tag_global', 'tag_local', 'tag_global', 'tagpath', 'global', 'set']]
   set tags=tagpath
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -736,7 +759,7 @@ func Test_OptionSet()
   " but the old local value for all other kinds of options.
   noa set tags=tag_global " Reset global and local value (without triggering autocmd)
   noa setlocal tags= " empty string
-  let g:options=[['tags', 'tag_global', '', 'tag_global', 'tagpath', 'global', 'set']]
+  let g:options = [['tags', 'tag_global', '', 'tag_global', 'tagpath', 'global', 'set']]
   set tags=tagpath
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -744,26 +767,26 @@ func Test_OptionSet()
 
   " 20a: Setting string local (to buffer) option"
   let oldval = &spelllang
-  let g:options=[['spelllang', oldval, oldval, oldval, 'elvish,klingon', 'global', 'set']]
+  let g:options = [['spelllang', oldval, oldval, oldval, 'elvish,klingon', 'global', 'set']]
   set spelllang=elvish,klingon
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 20b: Resetting string local (to buffer) option"
-  let g:options=[['spelllang', 'elvish,klingon', 'elvish,klingon', 'elvish,klingon', oldval, 'global', 'set']]
+  let g:options = [['spelllang', 'elvish,klingon', 'elvish,klingon', 'elvish,klingon', oldval, 'global', 'set']]
   set spelllang&
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 20c: Setting global string local (to buffer) option"
-  let g:options=[['spelllang', oldval, '', oldval, 'elvish', 'global', 'setglobal']]
+  let g:options = [['spelllang', oldval, '', oldval, 'elvish', 'global', 'setglobal']]
   setglobal spelllang=elvish
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 20d: Setting local string local (to buffer) option"
   noa set spelllang& " Reset global and local value (without triggering autocmd)
-  let g:options=[['spelllang', oldval, oldval, '', 'klingon', 'local', 'setlocal']]
+  let g:options = [['spelllang', oldval, oldval, '', 'klingon', 'local', 'setlocal']]
   setlocal spelllang=klingon
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -773,7 +796,7 @@ func Test_OptionSet()
   " but the old local value for all other kinds of options.
   noa setglobal spelllang=spellglobal " Reset global and local value (without triggering autocmd)
   noa setlocal spelllang=spelllocal
-  let g:options=[['spelllang', 'spelllocal', 'spelllocal', 'spellglobal', 'foo', 'global', 'set']]
+  let g:options = [['spelllang', 'spelllocal', 'spelllocal', 'spellglobal', 'foo', 'global', 'set']]
   set spelllang=foo
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -781,7 +804,7 @@ func Test_OptionSet()
 
   " 21a: Setting string local-global (to window) option"
   let oldval = &statusline
-  let g:options=[['statusline', oldval, oldval, oldval, 'foo', 'global', 'set']]
+  let g:options = [['statusline', oldval, oldval, oldval, 'foo', 'global', 'set']]
   set statusline=foo
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -789,20 +812,20 @@ func Test_OptionSet()
   " 21b: Resetting string local-global (to window) option"
   " Note: v:option_old is the old global value for local-global string options
   " but the old local value for all other kinds of options.
-  let g:options=[['statusline', 'foo', 'foo', 'foo', oldval, 'global', 'set']]
+  let g:options = [['statusline', 'foo', 'foo', 'foo', oldval, 'global', 'set']]
   set statusline&
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 21c: Setting global string local-global (to window) option"
-  let g:options=[['statusline', oldval, '', oldval, 'bar', 'global', 'setglobal']]
+  let g:options = [['statusline', oldval, '', oldval, 'bar', 'global', 'setglobal']]
   setglobal statusline=bar
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 21d: Setting local string local-global (to window) option"
   noa set statusline& " Reset global and local value (without triggering autocmd)
-  let g:options=[['statusline', oldval, oldval, '', 'baz', 'local', 'setlocal']]
+  let g:options = [['statusline', oldval, oldval, '', 'baz', 'local', 'setlocal']]
   setlocal statusline=baz
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -812,7 +835,7 @@ func Test_OptionSet()
   " but the old local value for all other kinds of options.
   noa setglobal statusline=bar " Reset global and local value (without triggering autocmd)
   noa setlocal statusline=baz
-  let g:options=[['statusline', 'bar', 'baz', 'bar', 'foo', 'global', 'set']]
+  let g:options = [['statusline', 'bar', 'baz', 'bar', 'foo', 'global', 'set']]
   set statusline=foo
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -820,26 +843,26 @@ func Test_OptionSet()
 
   " 22a: Setting string local (to window) option"
   let oldval = &foldignore
-  let g:options=[['foldignore', oldval, oldval, oldval, 'fo', 'global', 'set']]
+  let g:options = [['foldignore', oldval, oldval, oldval, 'fo', 'global', 'set']]
   set foldignore=fo
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 22b: Resetting string local (to window) option"
-  let g:options=[['foldignore', 'fo', 'fo', 'fo', oldval, 'global', 'set']]
+  let g:options = [['foldignore', 'fo', 'fo', 'fo', oldval, 'global', 'set']]
   set foldignore&
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 22c: Setting global string local (to window) option"
-  let g:options=[['foldignore', oldval, '', oldval, 'bar', 'global', 'setglobal']]
+  let g:options = [['foldignore', oldval, '', oldval, 'bar', 'global', 'setglobal']]
   setglobal foldignore=bar
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 22d: Setting local string local (to window) option"
   noa set foldignore& " Reset global and local value (without triggering autocmd)
-  let g:options=[['foldignore', oldval, oldval, '', 'baz', 'local', 'setlocal']]
+  let g:options = [['foldignore', oldval, oldval, '', 'baz', 'local', 'setlocal']]
   setlocal foldignore=baz
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -847,7 +870,7 @@ func Test_OptionSet()
   " 22e: Setting again string local (to window) option"
   noa setglobal foldignore=glob " Reset global and local value (without triggering autocmd)
   noa setlocal foldignore=loc
-  let g:options=[['foldignore', 'loc', 'loc', 'glob', 'fo', 'global', 'set']]
+  let g:options = [['foldignore', 'loc', 'loc', 'glob', 'fo', 'global', 'set']]
   set foldignore=fo
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -856,7 +879,7 @@ func Test_OptionSet()
   " 23a: Setting global number local option"
   noa setglobal cmdheight=8 " Reset global and local value (without triggering autocmd)
   noa setlocal cmdheight=1 " Sets the global(!) value!
-  let g:options=[['cmdheight', '1', '', '1', '2', 'global', 'setglobal']]
+  let g:options = [['cmdheight', '1', '', '1', '2', 'global', 'setglobal']]
   setglobal cmdheight=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -864,7 +887,7 @@ func Test_OptionSet()
   " 23b: Setting local number global option"
   noa setglobal cmdheight=8 " Reset global and local value (without triggering autocmd)
   noa setlocal cmdheight=1 " Sets the global(!) value!
-  let g:options=[['cmdheight', '1', '1', '', '2', 'local', 'setlocal']]
+  let g:options = [['cmdheight', '1', '1', '', '2', 'local', 'setlocal']]
   setlocal cmdheight=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -872,14 +895,14 @@ func Test_OptionSet()
   " 23c: Setting again number global option"
   noa setglobal cmdheight=8 " Reset global and local value (without triggering autocmd)
   noa setlocal cmdheight=1 " Sets the global(!) value!
-  let g:options=[['cmdheight', '1', '1', '1', '2', 'global', 'set']]
+  let g:options = [['cmdheight', '1', '1', '1', '2', 'global', 'set']]
   set cmdheight=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 23d: Setting again number global option"
   noa set cmdheight=8 " Reset global and local value (without triggering autocmd)
-  let g:options=[['cmdheight', '8', '8', '8', '2', 'global', 'set']]
+  let g:options = [['cmdheight', '8', '8', '8', '2', 'global', 'set']]
   set cmdheight=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -888,7 +911,7 @@ func Test_OptionSet()
   " 24a: Setting global number global-local (to buffer) option"
   noa setglobal undolevels=8 " Reset global and local value (without triggering autocmd)
   noa setlocal undolevels=1
-  let g:options=[['undolevels', '8', '', '8', '2', 'global', 'setglobal']]
+  let g:options = [['undolevels', '8', '', '8', '2', 'global', 'setglobal']]
   setglobal undolevels=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -896,7 +919,7 @@ func Test_OptionSet()
   " 24b: Setting local number global-local (to buffer) option"
   noa setglobal undolevels=8 " Reset global and local value (without triggering autocmd)
   noa setlocal undolevels=1
-  let g:options=[['undolevels', '1', '1', '', '2', 'local', 'setlocal']]
+  let g:options = [['undolevels', '1', '1', '', '2', 'local', 'setlocal']]
   setlocal undolevels=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -904,14 +927,14 @@ func Test_OptionSet()
   " 24c: Setting again number global-local (to buffer) option"
   noa setglobal undolevels=8 " Reset global and local value (without triggering autocmd)
   noa setlocal undolevels=1
-  let g:options=[['undolevels', '1', '1', '8', '2', 'global', 'set']]
+  let g:options = [['undolevels', '1', '1', '8', '2', 'global', 'set']]
   set undolevels=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 24d: Setting again global number global-local (to buffer) option"
   noa set undolevels=8 " Reset global and local value (without triggering autocmd)
-  let g:options=[['undolevels', '8', '8', '8', '2', 'global', 'set']]
+  let g:options = [['undolevels', '8', '8', '8', '2', 'global', 'set']]
   set undolevels=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -920,7 +943,7 @@ func Test_OptionSet()
   " 25a: Setting global number local (to buffer) option"
   noa setglobal wrapmargin=8 " Reset global and local value (without triggering autocmd)
   noa setlocal wrapmargin=1
-  let g:options=[['wrapmargin', '8', '', '8', '2', 'global', 'setglobal']]
+  let g:options = [['wrapmargin', '8', '', '8', '2', 'global', 'setglobal']]
   setglobal wrapmargin=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -928,7 +951,7 @@ func Test_OptionSet()
   " 25b: Setting local number local (to buffer) option"
   noa setglobal wrapmargin=8 " Reset global and local value (without triggering autocmd)
   noa setlocal wrapmargin=1
-  let g:options=[['wrapmargin', '1', '1', '', '2', 'local', 'setlocal']]
+  let g:options = [['wrapmargin', '1', '1', '', '2', 'local', 'setlocal']]
   setlocal wrapmargin=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -936,14 +959,14 @@ func Test_OptionSet()
   " 25c: Setting again number local (to buffer) option"
   noa setglobal wrapmargin=8 " Reset global and local value (without triggering autocmd)
   noa setlocal wrapmargin=1
-  let g:options=[['wrapmargin', '1', '1', '8', '2', 'global', 'set']]
+  let g:options = [['wrapmargin', '1', '1', '8', '2', 'global', 'set']]
   set wrapmargin=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 25d: Setting again global number local (to buffer) option"
   noa set wrapmargin=8 " Reset global and local value (without triggering autocmd)
-  let g:options=[['wrapmargin', '8', '8', '8', '2', 'global', 'set']]
+  let g:options = [['wrapmargin', '8', '8', '8', '2', 'global', 'set']]
   set wrapmargin=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -956,7 +979,7 @@ func Test_OptionSet()
   " 27a: Setting global number local (to window) option"
   noa setglobal foldcolumn=8 " Reset global and local value (without triggering autocmd)
   noa setlocal foldcolumn=1
-  let g:options=[['foldcolumn', '8', '', '8', '2', 'global', 'setglobal']]
+  let g:options = [['foldcolumn', '8', '', '8', '2', 'global', 'setglobal']]
   setglobal foldcolumn=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -964,7 +987,7 @@ func Test_OptionSet()
   " 27b: Setting local number local (to window) option"
   noa setglobal foldcolumn=8 " Reset global and local value (without triggering autocmd)
   noa setlocal foldcolumn=1
-  let g:options=[['foldcolumn', '1', '1', '', '2', 'local', 'setlocal']]
+  let g:options = [['foldcolumn', '1', '1', '', '2', 'local', 'setlocal']]
   setlocal foldcolumn=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -972,14 +995,14 @@ func Test_OptionSet()
   " 27c: Setting again number local (to window) option"
   noa setglobal foldcolumn=8 " Reset global and local value (without triggering autocmd)
   noa setlocal foldcolumn=1
-  let g:options=[['foldcolumn', '1', '1', '8', '2', 'global', 'set']]
+  let g:options = [['foldcolumn', '1', '1', '8', '2', 'global', 'set']]
   set foldcolumn=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 27d: Ssettin again global number local (to window) option"
   noa set foldcolumn=8 " Reset global and local value (without triggering autocmd)
-  let g:options=[['foldcolumn', '8', '8', '8', '2', 'global', 'set']]
+  let g:options = [['foldcolumn', '8', '8', '8', '2', 'global', 'set']]
   set foldcolumn=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -988,7 +1011,7 @@ func Test_OptionSet()
   " 28a: Setting global boolean global option"
   noa setglobal nowrapscan " Reset global and local value (without triggering autocmd)
   noa setlocal wrapscan " Sets the global(!) value!
-  let g:options=[['wrapscan', '1', '', '1', '0', 'global', 'setglobal']]
+  let g:options = [['wrapscan', '1', '', '1', '0', 'global', 'setglobal']]
   setglobal nowrapscan
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -996,7 +1019,7 @@ func Test_OptionSet()
   " 28b: Setting local boolean global option"
   noa setglobal nowrapscan " Reset global and local value (without triggering autocmd)
   noa setlocal wrapscan " Sets the global(!) value!
-  let g:options=[['wrapscan', '1', '1', '', '0', 'local', 'setlocal']]
+  let g:options = [['wrapscan', '1', '1', '', '0', 'local', 'setlocal']]
   setlocal nowrapscan
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1004,14 +1027,14 @@ func Test_OptionSet()
   " 28c: Setting again boolean global option"
   noa setglobal nowrapscan " Reset global and local value (without triggering autocmd)
   noa setlocal wrapscan " Sets the global(!) value!
-  let g:options=[['wrapscan', '1', '1', '1', '0', 'global', 'set']]
+  let g:options = [['wrapscan', '1', '1', '1', '0', 'global', 'set']]
   set nowrapscan
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 28d: Setting again global boolean global option"
   noa set nowrapscan " Reset global and local value (without triggering autocmd)
-  let g:options=[['wrapscan', '0', '0', '0', '1', 'global', 'set']]
+  let g:options = [['wrapscan', '0', '0', '0', '1', 'global', 'set']]
   set wrapscan
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1020,7 +1043,7 @@ func Test_OptionSet()
   " 29a: Setting global boolean global-local (to buffer) option"
   noa setglobal noautoread " Reset global and local value (without triggering autocmd)
   noa setlocal autoread
-  let g:options=[['autoread', '0', '', '0', '1', 'global', 'setglobal']]
+  let g:options = [['autoread', '0', '', '0', '1', 'global', 'setglobal']]
   setglobal autoread
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1028,7 +1051,7 @@ func Test_OptionSet()
   " 29b: Setting local boolean global-local (to buffer) option"
   noa setglobal noautoread " Reset global and local value (without triggering autocmd)
   noa setlocal autoread
-  let g:options=[['autoread', '1', '1', '', '0', 'local', 'setlocal']]
+  let g:options = [['autoread', '1', '1', '', '0', 'local', 'setlocal']]
   setlocal noautoread
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1036,14 +1059,14 @@ func Test_OptionSet()
   " 29c: Setting again boolean global-local (to buffer) option"
   noa setglobal noautoread " Reset global and local value (without triggering autocmd)
   noa setlocal autoread
-  let g:options=[['autoread', '1', '1', '0', '1', 'global', 'set']]
+  let g:options = [['autoread', '1', '1', '0', '1', 'global', 'set']]
   set autoread
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 29d: Setting again global boolean global-local (to buffer) option"
   noa set noautoread " Reset global and local value (without triggering autocmd)
-  let g:options=[['autoread', '0', '0', '0', '1', 'global', 'set']]
+  let g:options = [['autoread', '0', '0', '0', '1', 'global', 'set']]
   set autoread
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1052,7 +1075,7 @@ func Test_OptionSet()
   " 30a: Setting global boolean local (to buffer) option"
   noa setglobal nocindent " Reset global and local value (without triggering autocmd)
   noa setlocal cindent
-  let g:options=[['cindent', '0', '', '0', '1', 'global', 'setglobal']]
+  let g:options = [['cindent', '0', '', '0', '1', 'global', 'setglobal']]
   setglobal cindent
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1060,7 +1083,7 @@ func Test_OptionSet()
   " 30b: Setting local boolean local (to buffer) option"
   noa setglobal nocindent " Reset global and local value (without triggering autocmd)
   noa setlocal cindent
-  let g:options=[['cindent', '1', '1', '', '0', 'local', 'setlocal']]
+  let g:options = [['cindent', '1', '1', '', '0', 'local', 'setlocal']]
   setlocal nocindent
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1068,14 +1091,14 @@ func Test_OptionSet()
   " 30c: Setting again boolean local (to buffer) option"
   noa setglobal nocindent " Reset global and local value (without triggering autocmd)
   noa setlocal cindent
-  let g:options=[['cindent', '1', '1', '0', '1', 'global', 'set']]
+  let g:options = [['cindent', '1', '1', '0', '1', 'global', 'set']]
   set cindent
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 30d: Setting again global boolean local (to buffer) option"
   noa set nocindent " Reset global and local value (without triggering autocmd)
-  let g:options=[['cindent', '0', '0', '0', '1', 'global', 'set']]
+  let g:options = [['cindent', '0', '0', '0', '1', 'global', 'set']]
   set cindent
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1088,7 +1111,7 @@ func Test_OptionSet()
   " 32a: Setting global boolean local (to window) option"
   noa setglobal nocursorcolumn " Reset global and local value (without triggering autocmd)
   noa setlocal cursorcolumn
-  let g:options=[['cursorcolumn', '0', '', '0', '1', 'global', 'setglobal']]
+  let g:options = [['cursorcolumn', '0', '', '0', '1', 'global', 'setglobal']]
   setglobal cursorcolumn
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1096,7 +1119,7 @@ func Test_OptionSet()
   " 32b: Setting local boolean local (to window) option"
   noa setglobal nocursorcolumn " Reset global and local value (without triggering autocmd)
   noa setlocal cursorcolumn
-  let g:options=[['cursorcolumn', '1', '1', '', '0', 'local', 'setlocal']]
+  let g:options = [['cursorcolumn', '1', '1', '', '0', 'local', 'setlocal']]
   setlocal nocursorcolumn
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1104,14 +1127,14 @@ func Test_OptionSet()
   " 32c: Setting again boolean local (to window) option"
   noa setglobal nocursorcolumn " Reset global and local value (without triggering autocmd)
   noa setlocal cursorcolumn
-  let g:options=[['cursorcolumn', '1', '1', '0', '1', 'global', 'set']]
+  let g:options = [['cursorcolumn', '1', '1', '0', '1', 'global', 'set']]
   set cursorcolumn
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
 
   " 32d: Setting again global boolean local (to window) option"
   noa set nocursorcolumn " Reset global and local value (without triggering autocmd)
-  let g:options=[['cursorcolumn', '0', '0', '0', '1', 'global', 'set']]
+  let g:options = [['cursorcolumn', '0', '0', '0', '1', 'global', 'set']]
   set cursorcolumn
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1119,7 +1142,7 @@ func Test_OptionSet()
 
   " 33: Test autocommands when an option value is converted internally.
   noa set backspace=1 " Reset global and local value (without triggering autocmd)
-  let g:options=[['backspace', 'indent,eol', 'indent,eol', 'indent,eol', '2', 'global', 'set']]
+  let g:options = [['backspace', 'indent,eol', 'indent,eol', 'indent,eol', '2', 'global', 'set']]
   set backspace=2
   call assert_equal([], g:options)
   call assert_equal(g:opt[0], g:opt[1])
@@ -1139,7 +1162,7 @@ func Test_OptionSet_diffmode()
   call test_override('starting', 1)
   " 18: Changing an option when entering diff mode
   new
-  au OptionSet diff :let &l:cul=v:option_new
+  au OptionSet diff :let &l:cul = v:option_new
 
   call setline(1, ['buffer 1', 'line2', 'line3', 'line4'])
   call assert_equal(0, &l:cul)
@@ -2355,7 +2378,7 @@ func Test_autocmd_CmdWinEnter()
     autocmd CmdWinEnter * quit
     let winnr = winnr('$')
   END
-  let filename='XCmdWinEnter'
+  let filename = 'XCmdWinEnter'
   call writefile(lines, filename)
   let buf = RunVimInTerminal('-S '.filename, #{rows: 6})
 

src/testdir/test_python3.vim

@@ -12,6 +12,7 @@ func Create_vim_dict()
   return {'a': 1}
 endfunction
 
+let s:system_error_pat = 'Vim(py3):SystemError: \(<built-in function eval> returned NULL without setting an error\|error return without exception set\)'
 
 " This function should be called first. This sets up python functions used by
 " the other tests.
@@ -539,11 +540,11 @@ endfunc
 func Test_python3_list()
   " Try to convert a null List
   call AssertException(["py3 t = vim.eval('test_null_list()')"],
-        \ 'Vim(py3):SystemError: <built-in function eval> returned NULL without setting an error')
+        \ s:system_error_pat)
 
   " Try to convert a List with a null List item
   call AssertException(["py3 t = vim.eval('[test_null_list()]')"],
-        \ 'Vim(py3):SystemError: <built-in function eval> returned NULL without setting an error')
+        \ s:system_error_pat)
 
   " Try to bind a null List variable (works because an empty list is used)
   let cmds =<< trim END
@@ -582,11 +583,11 @@ endfunc
 func Test_python3_dict()
   " Try to convert a null Dict
   call AssertException(["py3 t = vim.eval('test_null_dict()')"],
-        \ 'Vim(py3):SystemError: <built-in function eval> returned NULL without setting an error')
+        \ s:system_error_pat)
 
   " Try to convert a Dict with a null List value
   call AssertException(["py3 t = vim.eval(\"{'a' : test_null_list()}\")"],
-        \ 'Vim(py3):SystemError: <built-in function eval> returned NULL without setting an error')
+        \ s:system_error_pat)
 
   " Try to convert a Dict with a null string key
   py3 t = vim.eval("{test_null_string() : 10}")
@@ -1119,7 +1120,7 @@ func Test_python3_list_slice()
   let l = [test_null_list()]
   py3 ll = vim.bindeval('l')
   call AssertException(["py3 x = ll[:]"],
-        \ "Vim(py3):SystemError: error return without exception set")
+        \ s:system_error_pat)
 endfunc
 
 " Vars

src/testdir/test_vim9_func.vim

@@ -299,6 +299,7 @@ def Test_nested_global_function()
       Outer()
   END
   CheckScriptFailure(lines, "E122:")
+  delfunc g:Inner
 
   lines =<< trim END
       vim9script
@@ -1565,6 +1566,25 @@ def Test_global_closure()
   bwipe!
 enddef
 
+def Test_global_closure_called_directly()
+  var lines =<< trim END
+      vim9script
+      def Outer()
+        var x = 1
+        def g:Inner()
+          var y = x
+          x += 1
+          assert_equal(1, y)
+        enddef
+        g:Inner()
+        assert_equal(2, x)
+      enddef
+      Outer()
+  END
+  CheckScriptSuccess(lines)
+  delfunc g:Inner
+enddef
+
 def Test_failure_in_called_function()
   # this was using the frame index as the return value
   var lines =<< trim END
@@ -1976,5 +1996,20 @@ def Test_dict_member_with_silent()
   CheckScriptSuccess(lines)
 enddef
 
+def Test_opfunc()
+  nnoremap <F3> <cmd>set opfunc=Opfunc<cr>g@
+  def g:Opfunc(_: any): string
+    setline(1, 'ASDF')
+    return ''
+  enddef
+  new
+  setline(1, 'asdf')
+  feedkeys("\<F3>$", 'x')
+  assert_equal('ASDF', getline(1))
+
+  bwipe!
+  nunmap <F3>
+enddef
+
 
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker

src/userfunc.c

@@ -1260,8 +1260,7 @@ func_clear(ufunc_T *fp, int force)
     // clear this function
     func_clear_items(fp);
     funccal_unref(fp->uf_scoped, fp, force);
-    if ((fp->uf_flags & FC_COPY) == 0)
-	clear_def_function(fp);
+    unlink_def_function(fp);
 }
 
 /*
@@ -1307,75 +1306,98 @@ func_clear_free(ufunc_T *fp, int force)
 /*
  * Copy already defined function "lambda" to a new function with name "global".
  * This is for when a compiled function defines a global function.
- * Caller should take care of adding a partial for a closure.
  */
-    ufunc_T *
-copy_func(char_u *lambda, char_u *global)
+    int
+copy_func(char_u *lambda, char_u *global, ectx_T *ectx)
 {
     ufunc_T *ufunc = find_func_even_dead(lambda, TRUE, NULL);
     ufunc_T *fp = NULL;
 
     if (ufunc == NULL)
-	semsg(_(e_lambda_function_not_found_str), lambda);
-    else
     {
-	// TODO: handle ! to overwrite
-	fp = find_func(global, TRUE, NULL);
-	if (fp != NULL)
-	{
-	    semsg(_(e_funcexts), global);
-	    return NULL;
-	}
-
-	fp = alloc_clear(offsetof(ufunc_T, uf_name) + STRLEN(global) + 1);
-	if (fp == NULL)
-	    return NULL;
-
-	fp->uf_varargs = ufunc->uf_varargs;
-	fp->uf_flags = (ufunc->uf_flags & ~FC_VIM9) | FC_COPY;
-	fp->uf_def_status = ufunc->uf_def_status;
-	fp->uf_dfunc_idx = ufunc->uf_dfunc_idx;
-	if (ga_copy_strings(&ufunc->uf_args, &fp->uf_args) == FAIL
-		|| ga_copy_strings(&ufunc->uf_def_args, &fp->uf_def_args)
-									== FAIL
-		|| ga_copy_strings(&ufunc->uf_lines, &fp->uf_lines) == FAIL)
-	    goto failed;
-
-	fp->uf_name_exp = ufunc->uf_name_exp == NULL ? NULL
-					     : vim_strsave(ufunc->uf_name_exp);
-	if (ufunc->uf_arg_types != NULL)
-	{
-	    fp->uf_arg_types = ALLOC_MULT(type_T *, fp->uf_args.ga_len);
-	    if (fp->uf_arg_types == NULL)
-		goto failed;
-	    mch_memmove(fp->uf_arg_types, ufunc->uf_arg_types,
-					sizeof(type_T *) * fp->uf_args.ga_len);
-	}
-	if (ufunc->uf_def_arg_idx != NULL)
-	{
-	    fp->uf_def_arg_idx = ALLOC_MULT(int, fp->uf_def_args.ga_len + 1);
-	    if (fp->uf_def_arg_idx == NULL)
-		goto failed;
-	    mch_memmove(fp->uf_def_arg_idx, ufunc->uf_def_arg_idx,
-				     sizeof(int) * fp->uf_def_args.ga_len + 1);
-	}
-	if (ufunc->uf_va_name != NULL)
-	{
-	    fp->uf_va_name = vim_strsave(ufunc->uf_va_name);
-	    if (fp->uf_va_name == NULL)
-		goto failed;
-	}
-	fp->uf_ret_type = ufunc->uf_ret_type;
-
-	fp->uf_refcount = 1;
-	STRCPY(fp->uf_name, global);
-	hash_add(&func_hashtab, UF2HIKEY(fp));
+	semsg(_(e_lambda_function_not_found_str), lambda);
+	return FAIL;
     }
-    return fp;
+
+    // TODO: handle ! to overwrite
+    fp = find_func(global, TRUE, NULL);
+    if (fp != NULL)
+    {
+	semsg(_(e_funcexts), global);
+	return FAIL;
+    }
+
+    fp = alloc_clear(offsetof(ufunc_T, uf_name) + STRLEN(global) + 1);
+    if (fp == NULL)
+	return FAIL;
+
+    fp->uf_varargs = ufunc->uf_varargs;
+    fp->uf_flags = (ufunc->uf_flags & ~FC_VIM9) | FC_COPY;
+    fp->uf_def_status = ufunc->uf_def_status;
+    fp->uf_dfunc_idx = ufunc->uf_dfunc_idx;
+    if (ga_copy_strings(&ufunc->uf_args, &fp->uf_args) == FAIL
+	    || ga_copy_strings(&ufunc->uf_def_args, &fp->uf_def_args)
+								    == FAIL
+	    || ga_copy_strings(&ufunc->uf_lines, &fp->uf_lines) == FAIL)
+	goto failed;
+
+    fp->uf_name_exp = ufunc->uf_name_exp == NULL ? NULL
+					 : vim_strsave(ufunc->uf_name_exp);
+    if (ufunc->uf_arg_types != NULL)
+    {
+	fp->uf_arg_types = ALLOC_MULT(type_T *, fp->uf_args.ga_len);
+	if (fp->uf_arg_types == NULL)
+	    goto failed;
+	mch_memmove(fp->uf_arg_types, ufunc->uf_arg_types,
+				    sizeof(type_T *) * fp->uf_args.ga_len);
+    }
+    if (ufunc->uf_def_arg_idx != NULL)
+    {
+	fp->uf_def_arg_idx = ALLOC_MULT(int, fp->uf_def_args.ga_len + 1);
+	if (fp->uf_def_arg_idx == NULL)
+	    goto failed;
+	mch_memmove(fp->uf_def_arg_idx, ufunc->uf_def_arg_idx,
+				 sizeof(int) * fp->uf_def_args.ga_len + 1);
+    }
+    if (ufunc->uf_va_name != NULL)
+    {
+	fp->uf_va_name = vim_strsave(ufunc->uf_va_name);
+	if (fp->uf_va_name == NULL)
+	    goto failed;
+    }
+    fp->uf_ret_type = ufunc->uf_ret_type;
+
+    fp->uf_refcount = 1;
+    STRCPY(fp->uf_name, global);
+    hash_add(&func_hashtab, UF2HIKEY(fp));
+
+    // the referenced dfunc_T is now used one more time
+    link_def_function(fp);
+
+    // Create a partial to store the context of the function, if not done
+    // already.
+    if ((ufunc->uf_flags & FC_CLOSURE) && ufunc->uf_partial == NULL)
+    {
+	partial_T   *pt = ALLOC_CLEAR_ONE(partial_T);
+
+	if (pt == NULL)
+	    goto failed;
+	if (fill_partial_and_closure(pt, ufunc, ectx) == FAIL)
+	    goto failed;
+	ufunc->uf_partial = pt;
+	--pt->pt_refcount;  // not referenced here yet
+    }
+    if (ufunc->uf_partial != NULL)
+    {
+	fp->uf_partial = ufunc->uf_partial;
+	++fp->uf_partial->pt_refcount;
+    }
+
+    return OK;
 
 failed:
     func_clear_free(fp, TRUE);
-    return NULL;
+    return FAIL;
 }
 
 static int	funcdepth = 0;
@@ -3515,7 +3537,7 @@ define_function(exarg_T *eap, char_u *name_arg)
 		fp->uf_profiling = FALSE;
 		fp->uf_prof_initialized = FALSE;
 #endif
-		clear_def_function(fp);
+		unlink_def_function(fp);
 	    }
 	}
     }

src/version.c

@@ -750,6 +750,14 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2188,
+/**/
+    2187,
+/**/
+    2186,
+/**/
+    2185,
 /**/
     2184,
 /**/

src/vim9.h

@@ -341,8 +341,10 @@ struct isn_S {
  */
 struct dfunc_S {
     ufunc_T	*df_ufunc;	    // struct containing most stuff
+    int		df_refcount;	    // how many ufunc_T point to this dfunc_T
     int		df_idx;		    // index in def_functions
     int		df_deleted;	    // if TRUE function was deleted
+    char_u	*df_name;	    // name used for error messages
 
     garray_T	df_def_args_isn;    // default argument instructions
     isn_T	*df_instr;	    // function body to be executed

src/vim9compile.c

@@ -7336,6 +7336,8 @@ add_def_function(ufunc_T *ufunc)
     dfunc->df_idx = def_functions.ga_len;
     ufunc->uf_dfunc_idx = dfunc->df_idx;
     dfunc->df_ufunc = ufunc;
+    dfunc->df_name = vim_strsave(ufunc->uf_name);
+    ++dfunc->df_refcount;
     ++def_functions.ga_len;
     return OK;
 }
@@ -7928,6 +7930,7 @@ erret:
 	for (idx = 0; idx < instr->ga_len; ++idx)
 	    delete_instr(((isn_T *)instr->ga_data) + idx);
 	ga_clear(instr);
+	VIM_CLEAR(dfunc->df_name);
 
 	// If using the last entry in the table and it was added above, we
 	// might as well remove it.
@@ -8102,9 +8105,7 @@ delete_instr(isn_T *isn)
 
 		if (ufunc != NULL)
 		{
-		    // Clear uf_dfunc_idx so that the function is deleted.
-		    clear_def_function(ufunc);
-		    ufunc->uf_dfunc_idx = 0;
+		    unlink_def_function(ufunc);
 		    func_ptr_unref(ufunc);
 		}
 
@@ -8206,7 +8207,7 @@ delete_instr(isn_T *isn)
 }
 
 /*
- * Free all instructions for "dfunc".
+ * Free all instructions for "dfunc" except df_name.
  */
     static void
 delete_def_function_contents(dfunc_T *dfunc)
@@ -8227,31 +8228,39 @@ delete_def_function_contents(dfunc_T *dfunc)
 
 /*
  * When a user function is deleted, clear the contents of any associated def
- * function.  The position in def_functions can be re-used.
+ * function, unless another user function still uses it.
+ * The position in def_functions can be re-used.
  */
     void
-clear_def_function(ufunc_T *ufunc)
+unlink_def_function(ufunc_T *ufunc)
 {
     if (ufunc->uf_dfunc_idx > 0)
     {
 	dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data)
 							 + ufunc->uf_dfunc_idx;
 
-	delete_def_function_contents(dfunc);
+	if (--dfunc->df_refcount <= 0)
+	    delete_def_function_contents(dfunc);
 	ufunc->uf_def_status = UF_NOT_COMPILED;
+	ufunc->uf_dfunc_idx = 0;
+	if (dfunc->df_ufunc == ufunc)
+	    dfunc->df_ufunc = NULL;
     }
 }
 
 /*
- * Used when a user function is about to be deleted: remove the pointer to it.
- * The entry in def_functions is then unused.
+ * Used when a user function refers to an existing dfunc.
  */
     void
-unlink_def_function(ufunc_T *ufunc)
+link_def_function(ufunc_T *ufunc)
 {
-    dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data) + ufunc->uf_dfunc_idx;
+    if (ufunc->uf_dfunc_idx > 0)
+    {
+	dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data)
+							 + ufunc->uf_dfunc_idx;
 
-    dfunc->df_ufunc = NULL;
+	++dfunc->df_refcount;
+    }
 }
 
 #if defined(EXITFREE) || defined(PROTO)
@@ -8268,6 +8277,7 @@ free_def_functions(void)
 	dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data) + idx;
 
 	delete_def_function_contents(dfunc);
+	vim_free(dfunc->df_name);
     }
 
     ga_clear(&def_functions);

src/vim9execute.c

@@ -54,7 +54,7 @@ typedef struct {
 /*
  * Execution context.
  */
-typedef struct {
+struct ectx_S {
     garray_T	ec_stack;	// stack of typval_T values
     int		ec_frame_idx;	// index in ec_stack: context of ec_dfunc_idx
 
@@ -69,7 +69,7 @@ typedef struct {
     int		ec_iidx;	// index in ec_instr: instruction to execute
 
     garray_T	ec_funcrefs;	// partials that might be a closure
-} ectx_T;
+};
 
 // Get pointer to item relative to the bottom of the stack, -1 is the last one.
 #define STACK_TV_BOT(idx) (((typval_T *)ectx->ec_stack.ga_data) + ectx->ec_stack.ga_len + (idx))
@@ -173,7 +173,9 @@ call_dfunc(int cdf_idx, int argcount_arg, ectx_T *ectx)
 
     if (dfunc->df_deleted)
     {
-	emsg_funcname(e_func_deleted, ufunc->uf_name);
+	// don't use ufunc->uf_name, it may have been freed
+	emsg_funcname(e_func_deleted,
+		dfunc->df_name == NULL ? (char_u *)"unknown" : dfunc->df_name);
 	return FAIL;
     }
 
@@ -260,6 +262,12 @@ call_dfunc(int cdf_idx, int argcount_arg, ectx_T *ectx)
     }
     ectx->ec_stack.ga_len += STACK_FRAME_SIZE + varcount;
 
+    if (ufunc->uf_partial != NULL)
+    {
+	ectx->ec_outer_stack = ufunc->uf_partial->pt_ectx_stack;
+	ectx->ec_outer_frame = ufunc->uf_partial->pt_ectx_frame;
+    }
+
     // Set execution state to the start of the called function.
     ectx->ec_dfunc_idx = cdf_idx;
     ectx->ec_instr = dfunc->df_instr;
@@ -618,6 +626,7 @@ call_ufunc(ufunc_T *ufunc, int argcount, ectx_T *ectx, isn_T *iptr)
 
 	// The function has been compiled, can call it quickly.  For a function
 	// that was defined later: we can call it directly next time.
+	// TODO: what if the function was deleted and then defined again?
 	if (iptr != NULL)
 	{
 	    delete_instr(iptr);
@@ -890,7 +899,7 @@ call_eval_func(char_u *name, int argcount, ectx_T *ectx, isn_T *iptr)
  * When a function reference is used, fill a partial with the information
  * needed, especially when it is used as a closure.
  */
-    static int
+    int
 fill_partial_and_closure(partial_T *pt, ufunc_T *ufunc, ectx_T *ectx)
 {
     pt->pt_func = ufunc;
@@ -2120,25 +2129,10 @@ call_def_function(
 	    case ISN_NEWFUNC:
 		{
 		    newfunc_T	*newfunc = &iptr->isn_arg.newfunc;
-		    ufunc_T	*new_ufunc;
 
-		    new_ufunc = copy_func(
-				       newfunc->nf_lambda, newfunc->nf_global);
-		    if (new_ufunc != NULL
-					 && (new_ufunc->uf_flags & FC_CLOSURE))
-		    {
-			partial_T   *pt = ALLOC_CLEAR_ONE(partial_T);
-
-			// Need to create a partial to store the context of the
-			// function.
-			if (pt == NULL)
-			    goto failed;
-			if (fill_partial_and_closure(pt, new_ufunc,
+		    if (copy_func(newfunc->nf_lambda, newfunc->nf_global,
 								&ectx) == FAIL)
-			    goto failed;
-			new_ufunc->uf_partial = pt;
-			--pt->pt_refcount;  // not referenced here
-		    }
+			goto failed;
 		}
 		break;