Index: src/vdbe.c
==================================================================
--- src/vdbe.c
+++ src/vdbe.c
@@ -1910,10 +1910,15 @@
   int res, res2;      /* Result of the comparison of pIn1 against pIn3 */
   char affinity;      /* Affinity to use for comparison */
   u16 flags1;         /* Copy of initial value of pIn1->flags */
   u16 flags3;         /* Copy of initial value of pIn3->flags */
 
+  /* The only way for P1 and P3 to be the same is when comparing constants.
+  ** But in that case, the affinities will always be SQLITE_AFF_BLOB or none */
+  assert( pOp->p1!=pOp->p3 || (pOp->p5 & SQLITE_AFF_MASK)<=SQLITE_AFF_BLOB );
+  testcase( pOp->p1==pOp->p3 );
+
   pIn1 = &aMem[pOp->p1];
   pIn3 = &aMem[pOp->p3];
   flags1 = pIn1->flags;
   flags3 = pIn3->flags;
   if( (flags1 | flags3)&MEM_Null ){
@@ -1957,11 +1962,15 @@
     affinity = pOp->p5 & SQLITE_AFF_MASK;
     if( affinity>=SQLITE_AFF_NUMERIC ){
       if( (flags1 | flags3)&MEM_Str ){
         if( (flags1 & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
           applyNumericAffinity(pIn1,0);
-          testcase( flags3!=pIn3->flags ); /* Possible if pIn1==pIn3 */
+          /* testcase( flags3!=pIn3->flags );
+          ** this used to be possible with pIn1==pIn3, but not since
+          ** the column cache was removed.  The following assignment
+          ** is essentially a no-op.  But, it prevents defense-in-depth
+          ** in case our analysis is incorrect, so it is left in. */
           flags3 = pIn3->flags;
         }
         if( (flags3 & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
           applyNumericAffinity(pIn3,0);
         }