diff --git a/accessible/src/base/nsCoreUtils.cpp b/accessible/src/base/nsCoreUtils.cpp
index ab8c1251ffa6..89047e0f4ab9 100644
--- a/accessible/src/base/nsCoreUtils.cpp
+++ b/accessible/src/base/nsCoreUtils.cpp
@@ -203,8 +203,7 @@ nsCoreUtils::GetDOMNodeFromDOMPoint(nsINode *aNode, PRUint32 aOffset)
 {
   if (aNode && aNode->IsElement()) {
     PRUint32 childCount = aNode->GetChildCount();
-    NS_ASSERTION(aOffset >= 0 && aOffset <= childCount,
-                 "Wrong offset of the DOM point!");
+    NS_ASSERTION(aOffset <= childCount, "Wrong offset of the DOM point!");
 
     // The offset can be after last child of container node that means DOM point
     // is placed immediately after the last child. In this case use the DOM node
diff --git a/accessible/src/generic/ARIAGridAccessible.cpp b/accessible/src/generic/ARIAGridAccessible.cpp
index 87179836ec02..cab9412d63dd 100644
--- a/accessible/src/generic/ARIAGridAccessible.cpp
+++ b/accessible/src/generic/ARIAGridAccessible.cpp
@@ -265,7 +265,7 @@ ARIAGridAccessible::SelectedCells(nsTArray<Accessible*>* aCells)
 void
 ARIAGridAccessible::SelectedCellIndices(nsTArray<PRUint32>* aCells)
 {
-  PRUint32 rowCount = RowCount(), colCount = ColCount();
+  PRUint32 colCount = ColCount();
 
   AccIterator rowIter(this, filters::GetRow);
   Accessible* row = nsnull;
diff --git a/accessible/src/generic/HyperTextAccessible.cpp b/accessible/src/generic/HyperTextAccessible.cpp
index 522dcab01f88..080e37085a89 100644
--- a/accessible/src/generic/HyperTextAccessible.cpp
+++ b/accessible/src/generic/HyperTextAccessible.cpp
@@ -1808,8 +1808,6 @@ HyperTextAccessible::SetSelectionBounds(PRInt32 aSelectionNum,
   if (rangeCount < static_cast<PRUint32>(aSelectionNum))
     return NS_ERROR_INVALID_ARG;
 
-  // Caret is a collapsed selection
-  bool isOnlyCaret = (aStartOffset == aEndOffset);
   nsRefPtr<nsRange> range;
   if (aSelectionNum == rangeCount)
     range = new nsRange();
diff --git a/accessible/src/html/HTMLTableAccessible.cpp b/accessible/src/html/HTMLTableAccessible.cpp
index bc3b900f2f79..f78714b7d253 100644
--- a/accessible/src/html/HTMLTableAccessible.cpp
+++ b/accessible/src/html/HTMLTableAccessible.cpp
@@ -36,6 +36,7 @@
 #include "nsArrayUtils.h"
 #include "nsComponentManagerUtils.h"
 
+using namespace mozilla;
 using namespace mozilla::a11y;
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -766,10 +767,11 @@ HTMLTableAccessible::ColExtentAt(PRUint32 aRowIdx, PRUint32 aColIdx)
   bool isSelected;
   PRInt32 columnExtent = 0;
 
-  tableLayout->
+  DebugOnly<nsresult> rv = tableLayout->
     GetCellDataAt(aRowIdx, aColIdx, *getter_AddRefs(domElement),
                   startRowIndex, startColIndex, rowSpan, colSpan,
                   actualRowSpan, columnExtent, isSelected);
+  NS_ASSERTION(NS_SUCCEEDED(rv), "Could not get cell data");
 
   return columnExtent;
 }
@@ -786,10 +788,11 @@ HTMLTableAccessible::RowExtentAt(PRUint32 aRowIdx, PRUint32 aColIdx)
   bool isSelected;
   PRInt32 rowExtent = 0;
 
-  tableLayout->
+  DebugOnly<nsresult> rv = tableLayout->
     GetCellDataAt(aRowIdx, aColIdx, *getter_AddRefs(domElement),
                   startRowIndex, startColIndex, rowSpan, colSpan,
                   rowExtent, actualColSpan, isSelected);
+  NS_ASSERTION(NS_SUCCEEDED(rv), "Could not get cell data");
 
   return rowExtent;
 }
diff --git a/accessible/src/xpcom/nsAccessibleRelation.h b/accessible/src/xpcom/nsAccessibleRelation.h
index 982d79bd5eaa..4134973b9d52 100644
--- a/accessible/src/xpcom/nsAccessibleRelation.h
+++ b/accessible/src/xpcom/nsAccessibleRelation.h
@@ -10,6 +10,7 @@
 
 #include "nsCOMPtr.h"
 #include "nsIMutableArray.h"
+#include "mozilla/Attributes.h"
 
 namespace mozilla {
 namespace a11y {
@@ -19,7 +20,7 @@ class Relation;
 /**
  * Class represents an accessible relation.
  */
-class nsAccessibleRelation : public nsIAccessibleRelation
+class nsAccessibleRelation MOZ_FINAL : public nsIAccessibleRelation
 {
 public:
   nsAccessibleRelation(PRUint32 aType, Relation* aRel);