From 09bede3b805d88c41c0e39a236c34f6ee9c4572c Mon Sep 17 00:00:00 2001
From: Robert Schadek <rschadek@symmetryinvestments.com>
Date: Mon, 27 Jan 2020 09:23:07 +0000
Subject: [PATCH] adding assert messages to rbtree

---
 std/container/rbtree.d | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/std/container/rbtree.d b/std/container/rbtree.d
index 41b3c2ad3..6540f93d9 100644
--- a/std/container/rbtree.d
+++ b/std/container/rbtree.d
@@ -183,7 +183,7 @@ struct RBNode(V)
     Node rotateR()
     in
     {
-        assert(_left !is null);
+        assert(_left !is null, "left node must not be null");
     }
     do
     {
@@ -226,7 +226,7 @@ struct RBNode(V)
     Node rotateL()
     in
     {
-        assert(_right !is null);
+        assert(_right !is null, "right node must not be null");
     }
     do
     {
@@ -255,7 +255,7 @@ struct RBNode(V)
     @property bool isLeftNode() const
     in
     {
-        assert(_parent !is null);
+        assert(_parent !is null, "parent must not be null");
     }
     do
     {
@@ -789,7 +789,8 @@ if (is(typeof(binaryFun!less(T.init, T.init))))
 
     private void _setup()
     {
-        assert(!_end); //Make sure that _setup isn't run more than once.
+        //Make sure that _setup isn't run more than once.
+        assert(!_end, "Setup must only be run once");
         _begin = _end = allocate();
     }