Does FILTER in SEQSCAN short-circuit AND?

Sample code:

SELECT *
FROM MyTable
WHERE foo = 'bar' AND MySlowFunc('foo') = 'bar'

Let's say this required a SEQSCAN because there were no indexes to support
column foo. For every row where foo <> 'bar' would the filter on the SEQSCAN
short-circuit the AND return false right away, or would it still execute
MySlowFunc('foo') ?

Thanks!

Carlo