commit https://github.com/vim/vim/commit/35a4cfa200917dd171b1fff3cd5b6cee9add673d Author: Bram Moolenaar <Bram@vim.org> Date: Sun Aug 14 16:07:48 2016 +0200 patch 7.4.2209 Problem: Cannot map <M-">. (Stephen Riehm) Solution: Solve the memory access problem in another way. (Dominique Pelle) Allow for using <M-\"> in a string.

--- a/src/syntax.c
+++ b/src/syntax.c
@@ -7939,7 +7939,7 @@ do_highlight(
 		 */
 		for (p = arg, off = 0; off < 100 - 6 && *p; )
 		{
-		    len = trans_special(&p, buf + off, FALSE);
+		    len = trans_special(&p, buf + off, FALSE, FALSE);
 		    if (len > 0)	    /* recognized special char */
 			off += len;
 		    else		    /* copy as normal char */