From be420ec875211cfc2be7f3b0e1d95435e0d079de Mon Sep 17 00:00:00 2001
From: Luis Lavena <luislavena@gmail.com>
Date: Tue, 15 Mar 2016 20:49:36 -0300
Subject: [PATCH] Fix incorrect return type

`Result#key` is expected to be `String`, yet Crystal considered
that by branching is possible result to be `nil`.

This was caused by *return-early* approach:

    def foo
      return @foo if @foo

      @foo = "awesome"
    end

    pp typeof(foo) # => String?

Changed to instead use memoization technique.
---
 src/radix/result.cr | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/src/radix/result.cr b/src/radix/result.cr
index d58fc0f..ca93480 100644
--- a/src/radix/result.cr
+++ b/src/radix/result.cr
@@ -61,15 +61,13 @@ module Radix
     # # => ""
     # ```
     def key : String
-      return @key if @key
-
-      key = String.build { |io|
-        @nodes.each do |node|
-          io << node.key
-        end
-      }
-
-      @key = key
+      @key ||= begin
+        String.build { |io|
+          @nodes.each do |node|
+            io << node.key
+          end
+        }
+      end
     end
 
     # Adjust result information by using the details of the given `Node`.