diff -Naur 1/src/alter.c 2/src/alter.c
--- 1/src/alter.c	2020-06-02 16:02:38.294309518 -0400
+++ 2/src/alter.c	2020-06-02 16:05:27.248309518 -0400
@@ -123,7 +123,10 @@
   /* Check that a table or index named 'zName' does not already exist
   ** in database iDb. If so, this is an error.
   */
-  if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
+  if( sqlite3FindTable(db, zName, zDb)
+   || sqlite3FindIndex(db, zName, zDb)
+   || sqlite3IsShadowTableOf(db, pTab, zName)
+  ){
     sqlite3ErrorMsg(pParse, 
         "there is already another table or index with this name: %s", zName);
     goto exit_rename_table;
diff -Naur 1/src/build.c 2/src/build.c
--- 1/src/build.c	2020-06-02 16:02:38.325309518 -0400
+++ 2/src/build.c	2020-06-02 16:11:12.023309518 -0400
@@ -2129,6 +2129,28 @@
   recomputeColumnsNotIndexed(pPk);
 }
 
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+ * ** Return true if pTab is a virtual table and zName is a shadow table name
+ * ** for that virtual table.
+ * */
+int sqlite3IsShadowTableOf(sqlite3 *db, Table *pTab, const char *zName){
+  int nName;                    /* Length of zName */
+  Module *pMod;                 /* Module for the virtual table */
+
+  if( !IsVirtual(pTab) ) return 0;
+  nName = sqlite3Strlen30(pTab->zName);
+  if( sqlite3_strnicmp(zName, pTab->zName, nName)!=0 ) return 0;
+  if( zName[nName]!='_' ) return 0;
+  pMod = (Module*)sqlite3HashFind(&db->aModule, pTab->azModuleArg[0]);
+  if( pMod==0 ) return 0;
+  if( pMod->pModule->iVersion<3 ) return 0;
+  if( pMod->pModule->xShadowName==0 ) return 0;
+  return pMod->pModule->xShadowName(zName+nName+1);
+}
+#endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */
+
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /*
 ** Return true if zName is a shadow table name in the current database
@@ -2140,7 +2162,6 @@
 int sqlite3ShadowTableName(sqlite3 *db, const char *zName){
   char *zTail;                  /* Pointer to the last "_" in zName */
   Table *pTab;                  /* Table that zName is a shadow of */
-  Module *pMod;                 /* Module for the virtual table */
 
   zTail = strrchr(zName, '_');
   if( zTail==0 ) return 0;
@@ -2149,11 +2170,7 @@
   *zTail = '_';
   if( pTab==0 ) return 0;
   if( !IsVirtual(pTab) ) return 0;
-  pMod = (Module*)sqlite3HashFind(&db->aModule, pTab->azModuleArg[0]);
-  if( pMod==0 ) return 0;
-  if( pMod->pModule->iVersion<3 ) return 0;
-  if( pMod->pModule->xShadowName==0 ) return 0;
-  return pMod->pModule->xShadowName(zTail+1);
+  return sqlite3IsShadowTableOf(db, pTab, zName);
 }
 #endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */
 
diff -Naur 1/src/sqliteInt.h 2/src/sqliteInt.h
--- 1/src/sqliteInt.h	2020-06-02 16:02:38.291309518 -0400
+++ 2/src/sqliteInt.h	2020-06-02 16:14:49.356309518 -0400
@@ -4673,8 +4673,10 @@
 int sqlite3ReadOnlyShadowTables(sqlite3 *db);
 #ifndef SQLITE_OMIT_VIRTUALTABLE
   int sqlite3ShadowTableName(sqlite3 *db, const char *zName);
+  int sqlite3IsShadowTableOf(sqlite3*,Table*,const char*);
 #else
 # define sqlite3ShadowTableName(A,B) 0
+# define sqlite3IsShadowTableOf(A,B,C) 0
 #endif
 int sqlite3VtabEponymousTableInit(Parse*,Module*);
 void sqlite3VtabEponymousTableClear(sqlite3*,Module*);