From 965cc82428e8cea868fbd35eca4ca05ddffcfabc Mon Sep 17 00:00:00 2001
From: Matthew Leon <ml@matthewleon.com>
Date: Mon, 1 Jan 2018 11:25:25 -0500
Subject: [PATCH 1/2] rename __unused constant to $unused

fixes https://github.com/purescript/purescript/issues/3187
---
 src/Language/PureScript/Constants.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Language/PureScript/Constants.hs b/src/Language/PureScript/Constants.hs
index 3703e07bf1..f48998afa2 100644
--- a/src/Language/PureScript/Constants.hs
+++ b/src/Language/PureScript/Constants.hs
@@ -421,7 +421,7 @@ symbol = "Symbol"
 -- Code Generation
 
 __unused :: forall a. (IsString a) => a
-__unused = "__unused"
+__unused = "$unused" -- $ avoids name clashing
 
 -- Modules
 

From 34d62e8eddce9b736bb1e98ae857d98b7fd4b6ff Mon Sep 17 00:00:00 2001
From: Matthew Leon <ml@matthewleon.com>
Date: Mon, 1 Jan 2018 13:09:44 -0500
Subject: [PATCH 2/2] add test for __unused name clash

---
 examples/passing/3187-UnusedNameClash.purs | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 examples/passing/3187-UnusedNameClash.purs

diff --git a/examples/passing/3187-UnusedNameClash.purs b/examples/passing/3187-UnusedNameClash.purs
new file mode 100644
index 0000000000..bd84f095b8
--- /dev/null
+++ b/examples/passing/3187-UnusedNameClash.purs
@@ -0,0 +1,12 @@
+module Main (main) where
+
+import Prelude ((+))
+import Control.Monad.Eff.Console (log)
+
+-- the __unused parameter used to get optimized away
+abuseUnused :: forall a. a -> a
+abuseUnused __unused = __unused
+
+main = do
+  let explode = abuseUnused 0 + abuseUnused 0
+  log "Done"