patch 8.2.2033: Vim9: :def without argument gives compilation error

Problem:    Vim9: :def without argument gives compilation error.
Solution:   Add the DEF instruction. (closes #7344)

src/ex_docmd.c

@@ -274,7 +274,6 @@ static void	ex_tag_cmd(exarg_T *eap, char_u *name);
 # define ex_continue		ex_ni
 # define ex_debug		ex_ni
 # define ex_debuggreedy		ex_ni
-# define ex_def			ex_ni
 # define ex_defcompile		ex_ni
 # define ex_delfunction		ex_ni
 # define ex_disassemble		ex_ni

src/proto/userfunc.pro

@@ -33,6 +33,7 @@ int call_func(char_u *funcname, int len, typval_T *rettv, int argcount_in, typva
 char_u *printable_func_name(ufunc_T *fp);
 char_u *trans_function_name(char_u **pp, int *is_global, int skip, int flags, funcdict_T *fdp, partial_T **partial);
 char_u *untrans_function_name(char_u *name);
+void list_functions(regmatch_T *regmatch);
 ufunc_T *define_function(exarg_T *eap, char_u *name_arg);
 void ex_function(exarg_T *eap);
 void ex_defcompile(exarg_T *eap);

src/testdir/test_vim9_disassemble.vim

@@ -905,6 +905,29 @@ def Test_nested_func()
         instr)
 enddef
 
+def NestedDefList()
+  def
+  def Info
+  def /Info
+  def /Info/
+enddef
+
+def Test_nested_def_list()
+   var instr = execute('disassemble NestedDefList')
+   assert_match('NestedDefList\_s*' ..
+        'def\_s*' ..
+        '\d DEF \_s*' ..
+        'def Info\_s*' ..
+        '\d DEF Info\_s*' ..
+        'def /Info\_s*' ..
+        '\d DEF /Info\_s*' ..
+        'def /Info/\_s*' ..
+        '\d DEF /Info/\_s*' ..
+        '\d PUSHNR 0\_s*' ..
+        '\d RETURN',
+        instr)
+enddef
+
 def AndOr(arg: any): string
   if arg == 1 && arg != 2 || arg == 4
     return 'yes'

src/testdir/test_vim9_func.vim

@@ -288,6 +288,33 @@ def Test_nested_global_function()
   CheckScriptFailure(lines, "E1073:")
 enddef
 
+def DefListAll()
+  def
+enddef
+
+def DefListOne()
+  def DefListOne
+enddef
+
+def DefListMatches()
+  def /DefList
+enddef
+
+def Test_nested_def_list()
+  var funcs = split(execute('call DefListAll()'), "\n")
+  assert_true(len(funcs) > 10)
+  assert_true(funcs->index('def DefListAll()') >= 0)
+
+  funcs = split(execute('call DefListOne()'), "\n")
+  assert_equal(['   def DefListOne()', '1    def DefListOne', '   enddef'], funcs)
+
+  funcs = split(execute('call DefListMatches()'), "\n")
+  assert_true(len(funcs) >= 3)
+  assert_true(funcs->index('def DefListAll()') >= 0)
+  assert_true(funcs->index('def DefListOne()') >= 0)
+  assert_true(funcs->index('def DefListMatches()') >= 0)
+enddef
+
 def Test_global_local_function()
   var lines =<< trim END
       vim9script

src/userfunc.c

@@ -2748,7 +2748,7 @@ untrans_function_name(char_u *name)
  * List functions.  When "regmatch" is NULL all of then.
  * Otherwise functions matching "regmatch".
  */
-    static void
+    void
 list_functions(regmatch_T *regmatch)
 {
     int		changed = func_hashtab.ht_changed;

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2033,
 /**/
     2032,
 /**/

src/vim9.h

@@ -82,6 +82,7 @@ typedef enum {
     ISN_RETURN,	    // return, result is on top of stack
     ISN_FUNCREF,    // push a function ref to dfunc isn_arg.funcref
     ISN_NEWFUNC,    // create a global function from a lambda function
+    ISN_DEF,	    // list functions
 
     // expression operations
     ISN_JUMP,	    // jump if condition is matched isn_arg.jump

src/vim9compile.c

@@ -1432,6 +1432,26 @@ generate_NEWFUNC(cctx_T *cctx, char_u *lambda_name, char_u *func_name)
     return OK;
 }
 
+/*
+ * Generate an ISN_DEF instruction: list functions
+ */
+    static int
+generate_DEF(cctx_T *cctx, char_u *name, size_t len)
+{
+    isn_T	*isn;
+
+    RETURN_OK_IF_SKIP(cctx);
+    if ((isn = generate_instr(cctx, ISN_DEF)) == NULL)
+	return FAIL;
+    if (len > 0)
+    {
+	isn->isn_arg.string = vim_strnsave(name, len);
+	if (isn->isn_arg.string == NULL)
+	    return FAIL;
+    }
+    return OK;
+}
+
 /*
  * Generate an ISN_JUMP instruction.
  */
@@ -4801,6 +4821,27 @@ compile_nested_function(exarg_T *eap, cctx_T *cctx)
 	return NULL;
     }
 
+    if (*name_start == '/')
+    {
+	name_end = skip_regexp(name_start + 1, '/', TRUE);
+	if (*name_end == '/')
+	    ++name_end;
+	eap->nextcmd = check_nextcmd(name_end);
+    }
+    if (name_end == name_start || *skipwhite(name_end) != '(')
+    {
+	if (!ends_excmd2(name_start, name_end))
+	{
+	    semsg(_(e_invalid_command_str), eap->cmd);
+	    return NULL;
+	}
+
+	// "def" or "def Name": list functions
+	if (generate_DEF(cctx, name_start, name_end - name_start) == FAIL)
+	    return NULL;
+	return eap->nextcmd == NULL ? (char_u *)"" : eap->nextcmd;
+    }
+
     // Only g:Func() can use a namespace.
     if (name_start[1] == ':' && !is_global)
     {
@@ -7736,22 +7777,23 @@ delete_instr(isn_T *isn)
 {
     switch (isn->isn_type)
     {
+	case ISN_DEF:
 	case ISN_EXEC:
+	case ISN_LOADB:
 	case ISN_LOADENV:
 	case ISN_LOADG:
-	case ISN_LOADB:
-	case ISN_LOADW:
-	case ISN_LOADT:
 	case ISN_LOADOPT:
-	case ISN_STRINGMEMBER:
+	case ISN_LOADT:
+	case ISN_LOADW:
 	case ISN_PUSHEXC:
+	case ISN_PUSHFUNC:
 	case ISN_PUSHS:
+	case ISN_STOREB:
 	case ISN_STOREENV:
 	case ISN_STOREG:
-	case ISN_STOREB:
-	case ISN_STOREW:
 	case ISN_STORET:
-	case ISN_PUSHFUNC:
+	case ISN_STOREW:
+	case ISN_STRINGMEMBER:
 	    vim_free(isn->isn_arg.string);
 	    break;
 

src/vim9execute.c

@@ -1970,6 +1970,20 @@ call_def_function(
 		}
 		break;
 
+	    // List functions
+	    case ISN_DEF:
+		if (iptr->isn_arg.string == NULL)
+		    list_functions(NULL);
+		else
+		{
+		    exarg_T ea;
+
+		    CLEAR_FIELD(ea);
+		    ea.cmd = ea.arg = iptr->isn_arg.string;
+		    define_function(&ea, NULL);
+		}
+		break;
+
 	    // jump if a condition is met
 	    case ISN_JUMP:
 		{
@@ -3371,6 +3385,15 @@ ex_disassemble(exarg_T *eap)
 		}
 		break;
 
+	    case ISN_DEF:
+		{
+		    char_u *name = iptr->isn_arg.string;
+
+		    smsg("%4d DEF %s", current,
+					   name == NULL ? (char_u *)"" : name);
+		}
+		break;
+
 	    case ISN_JUMP:
 		{
 		    char *when = "?";