patch 8.2.2761: using "syn include" does not work properly

Problem:    Using "syn include" does not work properly.
Solution:   Don't add current_syn_inc_tag to topgrp. (Jaehwang Jerry Jung,
            closes #8104)

src/syntax.c

@@ -5990,12 +5990,17 @@ get_id_list(
 		    break;
 		}
 		if (name[1] == 'A')
-		    id = SYNID_ALLBUT;
+		    id = SYNID_ALLBUT + current_syn_inc_tag;
 		else if (name[1] == 'T')
-		    id = SYNID_TOP;
+		{
+		    if (curwin->w_s->b_syn_topgrp >= SYNID_CLUSTER)
+			id = curwin->w_s->b_syn_topgrp;
+		    else
+			id = SYNID_TOP + current_syn_inc_tag;
+		}
 		else
-		    id = SYNID_CONTAINED;
-		id += current_syn_inc_tag;
+		    id = SYNID_CONTAINED + current_syn_inc_tag;
+
 	    }
 	    else if (name[1] == '@')
 	    {

src/testdir/test_syntax.vim

@@ -920,4 +920,21 @@ func Test_syn_contained_transparent()
   bw!
 endfunc
 
+func Test_syn_include_contains_TOP()
+  let l:case = "TOP in included syntax means its group list name"
+  new
+  syntax include @INCLUDED syntax/c.vim
+  syntax region FencedCodeBlockC start=/```c/ end=/```/ contains=@INCLUDED
+
+  call setline(1,  ['```c', '#if 0', 'int', '#else', 'int', '#endif', '```' ])
+  let l:expected = ["cCppOutIf2"]
+  eval AssertHighlightGroups(3, 1, l:expected, 1)
+  " cCppOutElse has contains=TOP
+  let l:expected = ["cType"]
+  eval AssertHighlightGroups(5, 1, l:expected, 1, l:case)
+  syntax clear
+  bw!
+endfunc
+
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2761,
 /**/
     2760,
 /**/