SQL Server 2017

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SET TRANSACTION ISOLATION LEVEL SNAPSHOT;

CREATE TABLE dbo.T (n integer NULL);
CREATE TRIGGER trg ON dbo.T
AFTER INSERT AS
BEGIN
    SELECT * INTO #i FROM Inserted
    CREATE INDEX i ON #i (n);
END;
SET IMPLICIT_TRANSACTIONS ON;

INSERT dbo.T (n) VALUES (1);

SET IMPLICIT_TRANSACTIONS OFF;
Msg 3964 Level 16 State 1 Line 5
Transaction failed because this DDL statement is not allowed inside a snapshot isolation transaction. Since metadata is not versioned, a metadata change can lead to inconsistency if mixed within snapshot isolation.