patch 8.1.0098: segfault when pattern with z() is very slow commit https://github.com/vim/vim/commit/bcf9442307075bac40d44328c8bf7ea21857b138 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Jun 23 14:21:42 2018 +0200 patch 8.1.0098: segfault when pattern with \z() is very slow Problem: Segfault when pattern with \z() is very slow. Solution: Check for NULL regprog. Add "nfa_fail" to test_override() to be able to test this. Fix that 'searchhl' resets called_emsg.

--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -8694,6 +8694,8 @@ test_override({name}, {val})				*test_ov
 		redraw       disable the redrawing() function
 		char_avail   disable the char_avail() function
 		starting     reset the "starting" variable, see below
+		nfa_fail     makes the NFA regexp engine fail to force a
+			     fallback to the old engine
 		ALL	     clear all overrides ({val} is not used)
 
 		"starting" is to be used when a test should behave like