From 4b386477ec20610cf7daec261474b9ee4380abad Mon Sep 17 00:00:00 2001
From: Brian Huffman <huffman@galois.com>
Date: Wed, 4 Oct 2017 21:22:59 -0700
Subject: [PATCH] Avoid creating a new option when :set is used with a prefix
 of a name.

Fixes #450.
---
 src/Cryptol/REPL/Monad.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Cryptol/REPL/Monad.hs b/src/Cryptol/REPL/Monad.hs
index 1d58c408..0784b119 100644
--- a/src/Cryptol/REPL/Monad.hs
+++ b/src/Cryptol/REPL/Monad.hs
@@ -538,7 +538,7 @@ setUser name val = case lookupTrieExact name userOptions of
                                     writeEnv v
     writeEnv ev =
       do optEff opt ev
-         modifyRW_ (\rw -> rw { eUserEnv = Map.insert name ev (eUserEnv rw) })
+         modifyRW_ (\rw -> rw { eUserEnv = Map.insert (optName opt) ev (eUserEnv rw) })
 
 splitOptArgs :: String -> [String]
 splitOptArgs  = unfoldr (parse "")