commit https://github.com/vim/vim/commit/437bafe4c8a83ed71ee006eda7f54b65a90f0d4c Author: Bram Moolenaar <Bram@vim.org> Date: Mon Aug 1 15:40:54 2016 +0200 patch 7.4.2137 Problem: Using function() with a name will find another function when it is redefined. Solution: Add funcref(). Refer to lambda using a partial. Fix several reference counting issues.

--- a/src/regexp.c
+++ b/src/regexp.c
@@ -7499,7 +7499,7 @@ vim_regsub_both(
 		    {
 			partial_T   *partial = expr->vval.v_partial;
 
-			s = partial->pt_name;
+			s = partial_name(partial);
 			call_func(s, (int)STRLEN(s), &rettv,
 					1, argv, fill_submatch_list,
 					  0L, 0L, &dummy, TRUE, partial, NULL);