From 109c9d551f7a00394b6211d8983ca0169a0e7fdf Mon Sep 17 00:00:00 2001
From: Matthew Baulch <baulch.matt@gmail.com>
Date: Tue, 5 Jul 2016 22:56:22 +1000
Subject: [PATCH] Regard nil nodes as having equal type constraints.

---
 compiler/types.nim | 1 +
 1 file changed, 1 insertion(+)

diff --git a/compiler/types.nim b/compiler/types.nim
index bada470756..107bd9f754 100644
--- a/compiler/types.nim
+++ b/compiler/types.nim
@@ -727,6 +727,7 @@ proc equalParam(a, b: PSym): TParamsEquality =
     result = paramsNotEqual
 
 proc sameConstraints(a, b: PNode): bool =
+  if isNil(a) and isNil(b): return true
   internalAssert a.len == b.len
   for i in 1 .. <a.len:
     if not exprStructuralEquivalent(a[i].sym.constraint,