Index: src/whereexpr.c
==================================================================
--- src/whereexpr.c
+++ src/whereexpr.c
@@ -1571,10 +1571,11 @@
   pTab = pItem->pTab;
   assert( pTab!=0 );
   pArgs = pItem->u1.pFuncArg;
   if( pArgs==0 ) return;
   for(j=k=0; j<pArgs->nExpr; j++){
+    Expr *pRhs;
     while( k<pTab->nCol && (pTab->aCol[k].colFlags & COLFLAG_HIDDEN)==0 ){k++;}
     if( k>=pTab->nCol ){
       sqlite3ErrorMsg(pParse, "too many arguments on %s() - max %d",
                       pTab->zName, j);
       return;
@@ -1582,10 +1583,11 @@
     pColRef = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0);
     if( pColRef==0 ) return;
     pColRef->iTable = pItem->iCursor;
     pColRef->iColumn = k++;
     pColRef->y.pTab = pTab;
-    pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef,
-                         sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0));
+    pRhs = sqlite3PExpr(pParse, TK_UPLUS, 
+        sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0), 0);
+    pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef, pRhs);
     whereClauseInsert(pWC, pTerm, TERM_DYNAMIC);
   }
 }

Index: test/bestindex4.test
==================================================================
--- test/bestindex4.test
+++ test/bestindex4.test
@@ -114,7 +114,60 @@
       }
     }
 
   }
 }
+
+#-------------------------------------------------------------------------
+# Test that a parameter passed to a table-valued function cannot be
+# used to drive an index. i.e. that in the following:
+#
+#   SELECT * FROM tbl, vtab(tbl.x);
+#
+# The implicit constraint "tbl.x = vtab.hidden" is not optimized using
+# an index on tbl.x.
+#
+reset_db
+register_tcl_module db
+proc vtab_command {method args} {
+  switch -- $method {
+    xConnect {
+      return "CREATE TABLE t1(a, b, c, d HIDDEN)"
+    }
+
+    xBestIndex {
+      set clist [lindex $args 0]
+      if {[llength $clist]!=1} { error "unexpected constraint list" }
+      catch { array unset C }
+      array set C [lindex $clist 0]
+      if {$C(usable)} {
+        return [list omit 0 idxnum 555 rows 10 cost 100]
+      }
+      return [list cost 100000000]
+    }
+
+  }
+
+  return {}
+}
+
+do_execsql_test 2.0 {
+  CREATE VIRTUAL TABLE x1 USING tcl(vtab_command);
+  CREATE TABLE t1 (x INT PRIMARY KEY);
+} {}
+
+do_execsql_test 2.1 {
+  EXPLAIN QUERY PLAN SELECT * FROM t1, x1 WHERE x1.d=t1.x;
+} {
+  3 0 0 {SCAN TABLE x1 VIRTUAL TABLE INDEX 0:}
+  7 0 0 {SEARCH TABLE t1 USING COVERING INDEX sqlite_autoindex_t1_1 (x=?)}
+}
+
+do_execsql_test 2.2 {
+  EXPLAIN QUERY PLAN SELECT * FROM t1, x1(t1.x)
+} {
+  3 0 0 {SCAN TABLE t1} 
+  5 0 0 {SCAN TABLE x1 VIRTUAL TABLE INDEX 555:}
+}
+
 
 finish_test