SQL Server Migrations: RenameIndex generates bad SQL when table unspecified

[Morcatko]

MigrationBuilder.RenameIndex(...) has an optional parameter "table". When this parameter is not provided rename/migration fails

Steps to reproduce

add this to any migration
migrationBuilder.RenameIndex("existingIndex", "newIndexName");

The issue

The migration is executed and fails with
Exception message: System.Data.SqlClient.SqlException (0x80131904): Either the parameter @objname is ambiguous or the claimed @objtype (INDEX) is wrong.

Stack:

   at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
   at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async, Int32 timeout, Boolean asyncWrite)
   at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean asyncWrite)
   at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
   at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.Execute(IRelationalConnection connection, String executeMethod, IReadOnlyDictionary`2 parameterValues, Boolean openConnection, Boolean closeConnection)
   at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.ExecuteNonQuery(IRelationalConnection connection, IReadOnlyDictionary`2 parameterValues,Boolean manageConnection)
   at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommandExtensions.ExecuteNonQuery(IEnumerable`1 commands, IRelationalConnection connection)
   at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Execute(IEnumerable`1 relationalCommands)
   at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration)
   at Microsoft.EntityFrameworkCore.Design.MigrationsOperations.UpdateDatabase(String targetMigration, String contextType)
   at Microsoft.EntityFrameworkCore.Tools.Cli.DatabaseUpdateCommand.<>c__DisplayClass0_0.<Configure>b__0()
   at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)
   at Microsoft.EntityFrameworkCore.Tools.Cli.Program.Main(String[] args)

Further technical details

The generated SQL looks like this:
EXEC sp_rename N'.existingIndex', N'newIndexName', N'INDEX'; - note the dot in first parameter

Rename SQL is generated here: https://github.com/aspnet/EntityFramework/blob/d5f39e3532c352c227a80ca40237a9121f17dc6e/src/Microsoft.EntityFrameworkCore.SqlServer/Migrations/SqlServerMigrationsSqlGenerator.cs#L113

RenameIndex method should have non-optional table parameter or there should be a check for non-empty string in the linked method to provide better logging.

EF Core version: 1.0.0-rc2-final
EF Core tools version: 1.0.0-preview1-final
Operating system: Win X
DB: SQL 12.0.2000
Visual Studio version: dotnet-cli

[bricelam]

We should check for nulls and throw when generating the SQL on SQL Server. The parameter is optional in the API because some databases (like PostgreSQL) only require the index name and schema.