patch 8.2.0253: crash when using :disassamble without argument

Problem:    Crash when using :disassamble without argument. (Dhiraj Mishra)
Solution:   Check for missing argument. (Dominique Pelle, closes #5635,
            closes #5637)

src/ex_cmds.h

@@ -479,7 +479,7 @@ EXCMD(CMD_digraphs,	"digraphs",	ex_digraphs,
 	EX_BANG|EX_EXTRA|EX_TRLBAR|EX_CMDWIN,
 	ADDR_NONE),
 EXCMD(CMD_disassemble,	"disassemble",	ex_disassemble,
-	EX_EXTRA|EX_TRLBAR|EX_CMDWIN,
+	EX_EXTRA|EX_NEEDARG|EX_TRLBAR|EX_CMDWIN,
 	ADDR_NONE),
 EXCMD(CMD_djump,	"djump",	ex_findpat,
 	EX_BANG|EX_RANGE|EX_DFLALL|EX_WHOLEFOLD|EX_EXTRA,

src/testdir/test_vim9_disassemble.vim

@@ -23,6 +23,10 @@ enddef
 def Test_disassemble_load()
   assert_fails('disass NoFunc', 'E1061:')
   assert_fails('disass NotCompiled', 'E1062:')
+  assert_fails('disass', 'E471:')
+  assert_fails('disass [', 'E475:')
+  assert_fails('disass 234', 'E475:')
+  assert_fails('disass <XX>foo', 'E475:')
 
   let res = execute('disass s:ScriptFuncLoad')
   assert_match('<SNR>\d*_ScriptFuncLoad.*'

src/version.c

@@ -742,6 +742,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    253,
 /**/
     252,
 /**/

src/vim9execute.c

@@ -1590,6 +1590,7 @@ call_def_function(
     void
 ex_disassemble(exarg_T *eap)
 {
+    char_u	*arg = eap->arg;
     char_u	*fname;
     ufunc_T	*ufunc;
     dfunc_T	*dfunc;
@@ -1598,8 +1599,14 @@ ex_disassemble(exarg_T *eap)
     int		line_idx = 0;
     int		prev_current = 0;
 
-    fname = trans_function_name(&eap->arg, FALSE,
+    fname = trans_function_name(&arg, FALSE,
 	     TFN_INT | TFN_QUIET | TFN_NO_AUTOLOAD | TFN_NO_DEREF, NULL, NULL);
+    if (fname == NULL)
+    {
+	semsg(_(e_invarg2), eap->arg);
+	return;
+    }
+
     ufunc = find_func(fname, NULL);
     vim_free(fname);
     if (ufunc == NULL)