From e0c9ff5544ad20cce3446cb095baf3c0ffd6640f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=98=88king?= <rking@sharpsaw.org>
Date: Thu, 13 Sep 2012 02:14:47 -0600
Subject: [PATCH] Make a common failure explain itself better.

---
 lib/pry/command_set.rb | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/pry/command_set.rb b/lib/pry/command_set.rb
index 900ff162..2a39d2e7 100644
--- a/lib/pry/command_set.rb
+++ b/lib/pry/command_set.rb
@@ -219,7 +219,8 @@ class Pry
     # @example Pass explicit description (overriding default).
     #   Pry.config.commands.alias_command "lM", "ls -M", :desc => "cutiepie"
     def alias_command(match, action,  options={})
-      original_options = find_command(action).options.dup
+      cmd = find_command(action) or fail "Command: `#{action}` not found"
+      original_options = cmd.options.dup
 
       options = original_options.merge!({
                                           :desc => "Alias for `#{action}`",