1 files changed, 1 insertions, 0 deletions
diff --git a/src/vdbesort.c b/src/vdbesort.c
index d76487d49..5a43a1054 100644
--- a/src/vdbesort.c
+++ b/src/vdbesort.c
@@ -2414,6 +2414,7 @@ int sqlite3VdbeSorterNext(sqlite3 *db, const VdbeCursor *pCsr, int *pbEof){
     }else
 #endif
     /*if( !pSorter->bUseThreads )*/ {
+      assert( pSorter->pMerger!=0 );
       assert( pSorter->pMerger->pTask==(&pSorter->aTask[0]) );
       rc = vdbeMergeEngineStep(pSorter->pMerger, pbEof);
     }