Index: src/walker.c
==================================================================
--- src/walker.c
+++ src/walker.c
@@ -118,12 +118,13 @@
   if( sqlite3WalkExpr(pWalker, p->pLimit) ) return WRC_Abort;
 #if !defined(SQLITE_OMIT_WINDOWFUNC) && !defined(SQLITE_OMIT_ALTERTABLE)
   {
     Parse *pParse = pWalker->pParse;
     if( pParse && IN_RENAME_OBJECT ){
+      /* The following may return WRC_Abort if there are unresolvable
+      ** symbols (e.g. a table that does not exist) in a window definition. */
       int rc = walkWindowList(pWalker, p->pWinDefn);
-      assert( rc==WRC_Continue );
       return rc;
     }
   }
 #endif
   return WRC_Continue;

Index: test/altertab3.test
==================================================================
--- test/altertab3.test
+++ test/altertab3.test
@@ -235,7 +235,42 @@
   {CREATE VIEW v1 AS SELECT * FROM t1 WHERE (
     SELECT t1.a FROM t1, t2
   ) IN () OR t1.a=5}
 }
 
+#-------------------------------------------------------------------------
+reset_db
+do_execsql_test 11.1 {
+  CREATE TABLE t1(
+      a,b,c,d,e,f,g,h,j,jj,jjb,k,aa,bb,cc,dd,ee DEFAULT 3.14,
+      ff DEFAULT('hiccup'),Wg NOD NULL DEFAULT(false)
+  );
+
+  CREATE TRIGGER b AFTER INSERT ON t1 WHEN new.a BEGIN
+    SELECT a, sum() w3 FROM t1 
+    WINDOW b AS (ORDER BY NOT EXISTS(SELECT 1 FROM abc));
+  END;
+}
+
+do_catchsql_test 11.2 {
+  ALTER TABLE t1 RENAME TO t1x;
+} {1 {error in trigger b: no such table: abc}}
+
+do_execsql_test 11.3 {
+  DROP TRIGGER b;
+  CREATE TRIGGER b AFTER INSERT ON t1 WHEN new.a BEGIN
+    SELECT a, sum() w3 FROM t1 
+    WINDOW b AS (ORDER BY NOT EXISTS(SELECT 1 FROM t1));
+  END;
+} {}
+
+do_execsql_test 11.4 {
+  ALTER TABLE t1 RENAME TO t1x;
+  SELECT sql FROM sqlite_master WHERE name = 'b';
+} {
+{CREATE TRIGGER b AFTER INSERT ON "t1x" WHEN new.a BEGIN
+    SELECT a, sum() w3 FROM "t1x" 
+    WINDOW b AS (ORDER BY NOT EXISTS(SELECT 1 FROM "t1x"));
+  END}
+}
 
 finish_test