5 files changed, 13 insertions, 5 deletions
diff --git a/src/alter.c b/src/alter.c
index e9640d238..b68e18914 100644
--- a/src/alter.c
+++ b/src/alter.c
@@ -1575,7 +1575,7 @@ static int renameTableSelectCb(Walker *pWalker, Select *pSelect){
   RenameCtx *p = pWalker->u.pRename;
   SrcList *pSrc = pSelect->pSrc;
   if( pSelect->selFlags & SF_View ) return WRC_Prune;
-  if( pSrc==0 ){
+  if( NEVER(pSrc==0) ){
     assert( pWalker->pParse->db->mallocFailed );
     return WRC_Abort;
   }
diff --git a/src/build.c b/src/build.c
index ecc08f60f..5506d36de 100644
--- a/src/build.c
+++ b/src/build.c
@@ -4595,8 +4595,8 @@ SrcList *sqlite3SrcListAppend(
 void sqlite3SrcListAssignCursors(Parse *pParse, SrcList *pList){
   int i;
   SrcItem *pItem;
-  assert(pList || pParse->db->mallocFailed );
-  if( pList ){
+  assert( pList || pParse->db->mallocFailed );
+  if( ALWAYS(pList) ){
     for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
       if( pItem->iCursor>=0 ) continue;
       pItem->iCursor = pParse->nTab++;
diff --git a/src/expr.c b/src/expr.c
index d9c8af65c..bd45fbcd1 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1648,6 +1648,14 @@ Select *sqlite3SelectDup(sqlite3 *db, Select *pDup, int flags){
     if( p->pWin && db->mallocFailed==0 ) gatherSelectWindows(pNew);
 #endif
     pNew->selId = p->selId;
+    if( db->mallocFailed ){
+      /* Any prior OOM might have left the Select object incomplete.
+      ** Delete the whole thing rather than allow an incomplete Select
+      ** to be used by the code generator. */
+      pNew->pNext = 0;
+      sqlite3SelectDelete(db, pNew);
+      break;
+    }
     *pp = pNew;
     pp = &pNew->pPrior;
     pNext = pNew;
diff --git a/src/select.c b/src/select.c
index 92c2ecf8f..6a773202e 100644
--- a/src/select.c
+++ b/src/select.c
@@ -4207,7 +4207,7 @@ static int flattenSubquery(
       p->pPrior = pPrior;
     }else{
       pNew->selId = ++pParse->nSelect;
-      if( aCsrMap && db->mallocFailed==0 ){
+      if( aCsrMap && ALWAYS(db->mallocFailed==0) ){
         renumberCursors(pParse, pNew, iFrom, aCsrMap);
       }
       pNew->pPrior = pPrior;
diff --git a/src/walker.c b/src/walker.c
index 28c80fa79..e0acd5de2 100644
--- a/src/walker.c
+++ b/src/walker.c
@@ -164,7 +164,7 @@ int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
   SrcItem *pItem;
 
   pSrc = p->pSrc;
-  if( pSrc ){
+  if( ALWAYS(pSrc) ){
     for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
       if( pItem->pSelect && sqlite3WalkSelect(pWalker, pItem->pSelect) ){
         return WRC_Abort;