Index: src/expr.c
==================================================================
--- src/expr.c
+++ src/expr.c
@@ -2241,10 +2241,19 @@
     }
     default: break;
   }
   return rc;
 }
+
+/*
+** Return true if p is a Column node that references a virtual table.
+*/
+int sqlite3ExprIsVtabRef(Expr *p){
+  if( p->op!=TK_COLUMN ) return 0;
+  if( p->y.pTab==0 ) return 0;
+  return IsVirtual(p->y.pTab);
+}
 
 /*
 ** Return FALSE if there is no chance that the expression can be NULL.
 **
 ** If the expression might be NULL or if the expression is too complex
@@ -5477,12 +5486,12 @@
       testcase( pExpr->op==TK_NE );
       testcase( pExpr->op==TK_LT );
       testcase( pExpr->op==TK_LE );
       testcase( pExpr->op==TK_GT );
       testcase( pExpr->op==TK_GE );
-      if( (pExpr->pLeft->op==TK_COLUMN && IsVirtual(pExpr->pLeft->y.pTab))
-       || (pExpr->pRight->op==TK_COLUMN && IsVirtual(pExpr->pRight->y.pTab))
+      if( sqlite3ExprIsVtabRef(pExpr->pLeft)
+       || sqlite3ExprIsVtabRef(pExpr->pRight)
       ){
        return WRC_Prune;
       }
 
     default:

Index: src/sqliteInt.h
==================================================================
--- src/sqliteInt.h
+++ src/sqliteInt.h
@@ -4276,10 +4276,11 @@
 int sqlite3ExprIsTableConstant(Expr*,int);
 #ifdef SQLITE_ENABLE_CURSOR_HINTS
 int sqlite3ExprContainsSubquery(Expr*);
 #endif
 int sqlite3ExprIsInteger(Expr*, int*);
+int sqlite3ExprIsVtabRef(Expr*);
 int sqlite3ExprCanBeNull(const Expr*);
 int sqlite3ExprNeedsNoAffinityChange(const Expr*, char);
 int sqlite3IsRowid(const char*);
 void sqlite3GenerateRowDelete(
     Parse*,Table*,Trigger*,int,int,int,i16,u8,u8,u8,int);

Index: src/whereexpr.c
==================================================================
--- src/whereexpr.c
+++ src/whereexpr.c
@@ -375,11 +375,11 @@
     **
     **       vtab_column MATCH expression
     **       MATCH(expression,vtab_column)
     */
     pCol = pList->a[1].pExpr;
-    if( pCol->op==TK_COLUMN && IsVirtual(pCol->y.pTab) ){
+    if( sqlite3ExprIsVtabRef(pCol) ){
       for(i=0; i<ArraySize(aOp); i++){
         if( sqlite3StrICmp(pExpr->u.zToken, aOp[i].zOp)==0 ){
           *peOp2 = aOp[i].eOp2;
           *ppRight = pList->a[0].pExpr;
           *ppLeft = pCol;
@@ -397,11 +397,11 @@
     ** Historically, xFindFunction expected to see lower-case function
     ** names.  But for this use case, xFindFunction is expected to deal
     ** with function names in an arbitrary case.
     */
     pCol = pList->a[0].pExpr;
-    if( pCol->op==TK_COLUMN && IsVirtual(pCol->y.pTab) ){
+    if( sqlite3ExprIsVtabRef(pCol) ){
       sqlite3_vtab *pVtab;
       sqlite3_module *pMod;
       void (*xNotUsed)(sqlite3_context*,int,sqlite3_value**);
       void *pNotUsed;
       pVtab = sqlite3GetVTable(db, pCol->y.pTab)->pVtab;
@@ -420,14 +420,14 @@
     }
   }else if( pExpr->op==TK_NE || pExpr->op==TK_ISNOT || pExpr->op==TK_NOTNULL ){
     int res = 0;
     Expr *pLeft = pExpr->pLeft;
     Expr *pRight = pExpr->pRight;
-    if( pLeft->op==TK_COLUMN && IsVirtual(pLeft->y.pTab) ){
+    if( sqlite3ExprIsVtabRef(pLeft) ){
       res++;
     }
-    if( pRight && pRight->op==TK_COLUMN && IsVirtual(pRight->y.pTab) ){
+    if( pRight && sqlite3ExprIsVtabRef(pRight) ){
       res++;
       SWAP(Expr*, pLeft, pRight);
     }
     *ppLeft = pLeft;
     *ppRight = pRight;