Index: src/walker.c
==================================================================
--- src/walker.c
+++ src/walker.c
@@ -23,15 +23,26 @@
 ** as the second argument.
 */
 static int walkWindowList(Walker *pWalker, Window *pList){
   Window *pWin;
   for(pWin=pList; pWin; pWin=pWin->pNextWin){
-    if( sqlite3WalkExprList(pWalker, pWin->pOrderBy) ) return WRC_Abort;
-    if( sqlite3WalkExprList(pWalker, pWin->pPartition) ) return WRC_Abort;
-    if( sqlite3WalkExpr(pWalker, pWin->pFilter) ) return WRC_Abort;
-    if( sqlite3WalkExpr(pWalker, pWin->pStart) ) return WRC_Abort;
-    if( sqlite3WalkExpr(pWalker, pWin->pEnd) ) return WRC_Abort;
+    int rc;
+    rc = sqlite3WalkExprList(pWalker, pWin->pOrderBy);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExprList(pWalker, pWin->pPartition);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExpr(pWalker, pWin->pFilter);
+    if( rc ) return WRC_Abort;
+
+    /* The next two are purely for calls to sqlite3RenameExprUnmap()
+    ** within sqlite3WindowOffsetExpr().  Because of constraints imposed
+    ** by sqlite3WindowOffsetExpr(), they can never fail.  The results do
+    ** not matter anyhow. */
+    rc = sqlite3WalkExpr(pWalker, pWin->pStart);
+    if( NEVER(rc) ) return WRC_Abort;
+    rc = sqlite3WalkExpr(pWalker, pWin->pEnd);
+    if( NEVER(rc) ) return WRC_Abort;
   }
   return WRC_Continue;
 }
 #endif