From 98ffcc1fd1bdd80f8229d9d2a759f63939914ce9 Mon Sep 17 00:00:00 2001
From: Michal Moskal <michal.moskal@microsoft.com>
Date: Sun, 25 Oct 2015 12:59:45 -0700
Subject: [PATCH] Add status panic codes for ref-count errors

---
 inc/ErrorNo.h         | 8 +++++++-
 source/RefCounted.cpp | 4 ++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/inc/ErrorNo.h b/inc/ErrorNo.h
index 84a37d6..19c6e62 100644
--- a/inc/ErrorNo.h
+++ b/inc/ErrorNo.h
@@ -22,6 +22,12 @@ enum Error{
     MICROBIT_OOM = 20, 
 
     // Corruption detected in the micro:bit heap space
-    MICROBIT_HEAP_ERROR = 30 
+    MICROBIT_HEAP_ERROR = 30,
+
+    // refcounter on an object is invalid (memory corruption)
+    MICROBIT_REF_COUNT_CORRUPTION = 31,
+
+    // refcounter was incremented/decremented after it already reached zero
+    MICROBIT_USE_AFTER_FREE = 32,
 };
 #endif
diff --git a/source/RefCounted.cpp b/source/RefCounted.cpp
index b8d646e..4ed60c1 100644
--- a/source/RefCounted.cpp
+++ b/source/RefCounted.cpp
@@ -16,10 +16,10 @@ static inline bool isReadOnlyInline(RefCounted *t)
 
     // Do some sanity checking while we're here
     if (refCount == 1)
-        uBit.panic(30); // object should have been deleted
+        uBit.panic(MICROBIT_USE_AFTER_FREE); // object should have been deleted
 
     if ((refCount & 1) == 0)
-        uBit.panic(31); // refCount doesn't look right
+        uBit.panic(MICROBIT_REF_COUNT_CORRUPTION); // refCount doesn't look right
 
     // Not read only
     return false;