makes c1 the primary key and uses the default index type (HASH for MEMORY engine).
If we want to use a BTREE index instead, then this does not work:
the SQL parser bails out at 'TYPE BTREE'
If written like so, it works again:
The request is to extend the parser to accept an index TYPE when a column definition contains an attribute that would add an index for that column. That is not just PRIMARY KEY, but also UNIQUE.