Index: src/where.c
==================================================================
--- src/where.c
+++ src/where.c
@@ -3687,11 +3687,11 @@
             if( sqlite3ExprCompare(0,
                   pOBExpr,pIndex->aColExpr->a[j].pExpr,iCur) ){
               continue;
             }
           }
-          if( iColumn>=0 ){
+          if( iColumn!=XN_ROWID ){
             pColl = sqlite3ExprCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
             if( !pColl ) pColl = db->pDfltColl;
             if( sqlite3StrICmp(pColl->zName, pIndex->azColl[j])!=0 ) continue;
           }
           pLoop->u.btree.nIdxCol = j+1;

Index: test/indexexpr2.test
==================================================================
--- test/indexexpr2.test
+++ test/indexexpr2.test
@@ -37,7 +37,104 @@
 }
 
 do_execsql_test 2.1 {
   SELECT a+1, quote(a+1) FROM t1 ORDER BY 1;
 } {2 2 3 3 4 4}
+
+#-------------------------------------------------------------------------
+# At one point SQLite was incorrectly using indexes on expressions to
+# optimize ORDER BY and GROUP BY clauses even when the collation
+# sequences of the query and index did not match (ticket [e20dd54ab0e4]).
+# The following tests - 3.* - attempt to verify that this has been fixed.
+#
+
+reset_db
+do_execsql_test 3.1.0 {
+  CREATE TABLE t1(a, b);
+  CREATE INDEX i1 ON t1(a, b);
+} {}
+
+do_eqp_test 3.1.1 {
+  SELECT b FROM t1 WHERE b IS NOT NULL AND a IS NULL 
+  GROUP BY b COLLATE nocase
+  ORDER BY b COLLATE nocase;
+} {
+  0 0 0 {SEARCH TABLE t1 USING COVERING INDEX i1 (a=? AND b>?)}
+  0 0 0 {USE TEMP B-TREE FOR GROUP BY}
+}
+
+do_execsql_test 3.2.0 {
+  CREATE TABLE t2(x);
+
+  INSERT INTO t2 VALUES('.ABC');
+  INSERT INTO t2 VALUES('.abcd');
+  INSERT INTO t2 VALUES('.defg');
+  INSERT INTO t2 VALUES('.DEF');
+} {}
+
+do_execsql_test 3.2.1 {
+  SELECT x FROM t2 ORDER BY substr(x, 2) COLLATE nocase;
+} {
+  .ABC .abcd .DEF .defg
+}
+
+do_execsql_test 3.2.2 {
+  CREATE INDEX i2 ON t2( substr(x, 2) );
+  SELECT x FROM t2 ORDER BY substr(x, 2) COLLATE nocase;
+} {
+  .ABC .abcd .DEF .defg
+}
+
+do_execsql_test 3.3.0 {
+  CREATE TABLE t3(x);
+}
+
+do_eqp_test 3.3.1 {
+  SELECT json_extract(x, '$.b') FROM t2 
+  WHERE json_extract(x, '$.b') IS NOT NULL AND json_extract(x, '$.a') IS NULL 
+  GROUP BY json_extract(x, '$.b') COLLATE nocase
+  ORDER BY json_extract(x, '$.b') COLLATE nocase;
+} {
+  0 0 0 {SCAN TABLE t2} 
+  0 0 0 {USE TEMP B-TREE FOR GROUP BY}
+}
+
+do_execsql_test 3.3.2 {
+  CREATE INDEX i3 ON t3(json_extract(x, '$.a'), json_extract(x, '$.b'));
+} {}
+
+do_eqp_test 3.3.3 {
+  SELECT json_extract(x, '$.b') FROM t3 
+  WHERE json_extract(x, '$.b') IS NOT NULL AND json_extract(x, '$.a') IS NULL 
+  GROUP BY json_extract(x, '$.b') COLLATE nocase
+  ORDER BY json_extract(x, '$.b') COLLATE nocase;
+} {
+  0 0 0 {SEARCH TABLE t3 USING INDEX i3 (<expr>=?)} 
+  0 0 0 {USE TEMP B-TREE FOR GROUP BY}
+}
+
+do_execsql_test 3.4.0 {
+  CREATE TABLE t4(a, b);
+  INSERT INTO t4 VALUES('.ABC', 1);
+  INSERT INTO t4 VALUES('.abc', 2);
+  INSERT INTO t4 VALUES('.ABC', 3);
+  INSERT INTO t4 VALUES('.abc', 4);
+}
+
+do_execsql_test 3.4.1 {
+  SELECT * FROM t4 
+  WHERE substr(a, 2) = 'abc' COLLATE NOCASE
+  ORDER BY substr(a, 2), b;
+} {
+  .ABC 1   .ABC 3   .abc 2   .abc 4
+}
+
+do_execsql_test 3.4.2 {
+  CREATE INDEX i4 ON t4( substr(a, 2) COLLATE NOCASE, b );
+  SELECT * FROM t4 
+  WHERE substr(a, 2) = 'abc' COLLATE NOCASE
+  ORDER BY substr(a, 2), b;
+} {
+  .ABC 1   .ABC 3   .abc 2   .abc 4
+}
 
 finish_test