patch 8.2.1003: Vim9: return type of sort() is too generic

Problem:    Vim9: return type of sort() is too generic.
Solution:   Get type from the first argument. (closes #6292)

src/evalfunc.c

@@ -339,6 +339,14 @@ ret_job(int argcount UNUSED, type_T **argtypes UNUSED)
     return &t_job;
 }
 
+    static type_T *
+ret_first_arg(int argcount, type_T **argtypes)
+{
+    if (argcount > 0)
+	return argtypes[0];
+    return &t_void;
+}
+
 static type_T *ret_f_function(int argcount, type_T **argtypes);
 
 /*
@@ -849,7 +857,7 @@ static funcentry_T global_functions[] =
     {"simplify",	1, 1, FEARG_1,	  ret_string,	f_simplify},
     {"sin",		1, 1, FEARG_1,	  ret_float,	FLOAT_FUNC(f_sin)},
     {"sinh",		1, 1, FEARG_1,	  ret_float,	FLOAT_FUNC(f_sinh)},
-    {"sort",		1, 3, FEARG_1,	  ret_list_any,	f_sort},
+    {"sort",		1, 3, FEARG_1,	  ret_first_arg, f_sort},
     {"sound_clear",	0, 0, 0,	  ret_void,	SOUND_FUNC(f_sound_clear)},
     {"sound_playevent",	1, 2, FEARG_1,	  ret_number,	SOUND_FUNC(f_sound_playevent)},
     {"sound_playfile",	1, 2, FEARG_1,	  ret_number,	SOUND_FUNC(f_sound_playfile)},

src/testdir/test_vim9_func.vim

@@ -807,5 +807,10 @@ def Test_call_closure_not_compiled()
   assert_equal('sometext', GetResult(g:Ref))
 enddef
 
+def Test_sort_return_type()
+  let res: list<number>
+  res = [1, 2, 3]->sort()
+enddef
+
 
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1003,
 /**/
     1002,
 /**/