Index: src/select.c
==================================================================
--- src/select.c
+++ src/select.c
@@ -4535,16 +4535,16 @@
            && OptimizationEnabled(db, SQLITE_SubqCoroutine)
     ){
       /* Implement a co-routine that will return a single row of the result
       ** set on each invocation.
       */
-      int addrTop;
+      int addrTop = sqlite3VdbeCurrentAddr(v)+1;
       pItem->regReturn = ++pParse->nMem;
-      sqlite3VdbeAddOp0(v, OP_Goto);
-      addrTop = sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor);
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pItem->regReturn, 0, addrTop);
+      VdbeComment((v, "%s", pItem->pTab->zName));
+      sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor);
       sqlite3VdbeChangeP5(v, 1);
-      VdbeComment((v, "coroutine %s", pItem->pTab->zName));
       pItem->addrFillSub = addrTop;
       sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn);
       explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
       sqlite3Select(pParse, pSub, &dest);
       pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
@@ -4565,16 +4565,18 @@
       int retAddr;
       assert( pItem->addrFillSub==0 );
       pItem->regReturn = ++pParse->nMem;
       topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn);
       pItem->addrFillSub = topAddr+1;
-      VdbeNoopComment((v, "materialize %s", pItem->pTab->zName));
       if( pItem->isCorrelated==0 ){
         /* If the subquery is not correlated and if we are not inside of
         ** a trigger, then we only need to compute the value of the subquery
         ** once. */
         onceAddr = sqlite3CodeOnce(pParse);
+        VdbeComment((v, "materialize \"%s\"", pItem->pTab->zName));
+      }else{
+        VdbeNoopComment((v, "materialize \"%s\"", pItem->pTab->zName));
       }
       sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
       explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
       sqlite3Select(pParse, pSub, &dest);
       pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;

Index: src/where.c
==================================================================
--- src/where.c
+++ src/where.c
@@ -2785,11 +2785,11 @@
   /* Special case of a FROM clause subquery implemented as a co-routine */
   if( pTabItem->viaCoroutine ){
     int regYield = pTabItem->regReturn;
     sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pTabItem->addrFillSub);
     pLevel->p2 =  sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk);
-    VdbeComment((v, "next row of co-routine %s", pTabItem->pTab->zName));
+    VdbeComment((v, "next row of \"%s\"", pTabItem->pTab->zName));
     pLevel->op = OP_Goto;
   }else
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
   if(  (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){