diff -r 000000000000 -r 6474c204b198 dom/xslt/xpath/txUnionExpr.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/xslt/xpath/txUnionExpr.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "txExpr.h"
+#include "txIXPathContext.h"
+#include "txNodeSet.h"
+
+  //-------------/
+ //- UnionExpr -/
+//-------------/
+
+    //-----------------------------/
+  //- Virtual methods from Expr -/
+//-----------------------------/
+
+/**
+ * Evaluates this Expr based on the given context node and processor state
+ * @param context the context node for evaluation of this Expr
+ * @param ps the ContextState containing the stack information needed
+ * for evaluation
+ * @return the result of the evaluation
+**/
+nsresult
+UnionExpr::evaluate(txIEvalContext* aContext, txAExprResult** aResult)
+{
+    *aResult = nullptr;
+    nsRefPtr<txNodeSet> nodes;
+    nsresult rv = aContext->recycler()->getNodeSet(getter_AddRefs(nodes));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    uint32_t i, len = mExpressions.Length();
+    for (i = 0; i < len; ++i) {
+        nsRefPtr<txAExprResult> exprResult;
+        rv = mExpressions[i]->evaluate(aContext, getter_AddRefs(exprResult));
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        if (exprResult->getResultType() != txAExprResult::NODESET) {
+            //XXX ErrorReport: report nonnodeset error
+            return NS_ERROR_XSLT_NODESET_EXPECTED;
+        }
+
+        nsRefPtr<txNodeSet> resultSet, ownedSet;
+        resultSet = static_cast<txNodeSet*>
+                               (static_cast<txAExprResult*>(exprResult));
+        exprResult = nullptr;
+        rv = aContext->recycler()->
+            getNonSharedNodeSet(resultSet, getter_AddRefs(ownedSet));
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        rv = nodes->addAndTransfer(ownedSet);
+        NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    *aResult = nodes;
+    NS_ADDREF(*aResult);
+
+    return NS_OK;
+} //-- evaluate
+
+Expr::ExprType
+UnionExpr::getType()
+{
+  return UNION_EXPR;
+}
+
+TX_IMPL_EXPR_STUBS_LIST(UnionExpr, NODESET_RESULT, mExpressions)
+
+bool
+UnionExpr::isSensitiveTo(ContextSensitivity aContext)
+{
+    uint32_t i, len = mExpressions.Length();
+    for (i = 0; i < len; ++i) {
+        if (mExpressions[i]->isSensitiveTo(aContext)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+#ifdef TX_TO_STRING
+void
+UnionExpr::toString(nsAString& dest)
+{
+    uint32_t i;
+    for (i = 0; i < mExpressions.Length(); ++i) {
+        if (i > 0)
+            dest.AppendLiteral(" | ");
+        mExpressions[i]->toString(dest);
+    }
+}
+#endif