- A :func:`.bindparam` construct with a "null" type (e.g. no type

- A :func:`.bindparam` construct with a "null" type (e.g. no type
specified) is now copied when used in a typed expression, and the
new copy is assigned the actual type of the compared column.  Previously,
this logic would occur on the given :func:`.bindparam` in place.
Additionally, a similar process now occurs for :func:`.bindparam` constructs
passed to :meth:`.ValuesBase.values` for a :class:`.Insert` or
:class:`.Update` construct. [ticket:2850]