title: String is too long and would be truncated
body: <p>Query:</p>
  <pre class="lang-sql prettyprint-override"><code>CREATE TABLE SRC(SRC_STRING VARCHAR(20))
  CREATE OR REPLACE TABLE TGT(tgt_STRING VARCHAR(10))
  
  INSERT INTO SRC VALUES('JKNHJYGHTFGRTYGHJ')
  
  INSERT INTO TGT(TGT_STRING) SELECT SRC_STRING::VARCHAR(10) FROM SRC
  </code></pre>
  <pre><code>Error: String 'JKNHJYGHTFGRTYGHJ' is too long and would be truncated
  </code></pre>
  <p>Is there any way we can enable enforce length(not for COPY command)  while inserting data from high precision to low precision column?</p>