From 38e1e6335c144fe52eb908e63c6b2cad5a1006ab Mon Sep 17 00:00:00 2001
From: Junegunn Choi <junegunn.c@gmail.com>
Date: Sun, 15 Nov 2015 22:43:25 +0900
Subject: [PATCH] Case-sensitive validation of on arguments (#314)

---
 plug.vim | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/plug.vim b/plug.vim
index 6541ace..80f9629 100644
--- a/plug.vim
+++ b/plug.vim
@@ -175,11 +175,14 @@ function! plug#end()
             call s:assoc(lod.map, cmd, name)
           endif
           call add(s:triggers[name].map, cmd)
-        elseif cmd =~ '^[A-Z]'
+        elseif cmd =~# '^[A-Z]'
           if exists(':'.cmd) != 2
             call s:assoc(lod.cmd, cmd, name)
           endif
           call add(s:triggers[name].cmd, cmd)
+        else
+          call s:err('Invalid `on` option: '.cmd.
+          \ '. Should start with an uppercase letter or `<Plug>`.')
         endif
       endfor
     endif