diff --git a/zsh-syntax-highlighting.zsh b/zsh-syntax-highlighting.zsh
index d100edb..96243fe 100644
--- a/zsh-syntax-highlighting.zsh
+++ b/zsh-syntax-highlighting.zsh
@@ -1,3 +1,4 @@
+() { # that's here to make the line numbers in errors match the file line numbers.
 # -------------------------------------------------------------------------------------------------
 # Copyright (c) 2010-2016 zsh-syntax-highlighting contributors
 # All rights reserved.
@@ -28,13 +29,17 @@
 # -------------------------------------------------------------------------------------------------
 
 # First of all, ensure predictable parsing.
-zsh_highlight__aliases=`builtin alias -Lm '[^+]*'`
+local zsh_highlight__aliases="$(builtin alias -Lm '[^+]*')"
 # In zsh <= 5.2, `alias -L` emits aliases that begin with a plus sign ('alias -- +foo=42')
 # them without a '--' guard, so they don't round trip.
 #
 # Hence, we exclude them from unaliasing:
 builtin unalias -m '[^+]*'
 
+# Set the 5.4-to-be WARN_NESTED_VAR option if it's available.
+emulate -L zsh
+setopt localoptions warncreateglobal ${(k)options[(I)warnnestedvar]}
+
 # Set $0 to the expected value, regardless of functionargzero.
 0=${(%):-%N}
 if true; then
@@ -45,7 +50,7 @@ if true; then
     # When running from a source tree without 'make install', $ZSH_HIGHLIGHT_REVISION
     # would be set to '$Format:%H$' literally.  That's an invalid value, and obtaining
     # the valid value (via `git rev-parse HEAD`, as Makefile does) might be costly, so:
-    ZSH_HIGHLIGHT_REVISION=HEAD
+    typeset -g ZSH_HIGHLIGHT_REVISION=HEAD
   fi
 fi
 
@@ -428,7 +433,7 @@ add-zsh-hook preexec _zsh_highlight_preexec_hook 2>/dev/null || {
 zmodload zsh/parameter 2>/dev/null || true
 
 # Initialize the array of active highlighters if needed.
-[[ $#ZSH_HIGHLIGHT_HIGHLIGHTERS -eq 0 ]] && ZSH_HIGHLIGHT_HIGHLIGHTERS=(main)
+[[ $#ZSH_HIGHLIGHT_HIGHLIGHTERS -eq 0 ]] && ZSH_HIGHLIGHT_HIGHLIGHTERS[1]=main
 
 # Restore the aliases we unned
 eval "$zsh_highlight__aliases"
@@ -436,3 +441,6 @@ builtin unset zsh_highlight__aliases
 
 # Set $?.
 true
+
+# End anonymous function
+}