The option ``--optimize-ast`` will control the peephole optimizer,
which is used to optimize a couple of AST subtrees. The current problem
solved by the peephole optimizer is when multiple joined strings,
with the addition operator, are encountered. If the numbers of such
strings is high enough, Pylint will then fail with a maximum recursion
depth exceeded error, due to its visitor architecture. The peephole
just transforms such calls, if it can, into the final resulting string
and this exhibit a problem, because the visit_binop method stops being
called (in the optimized AST it will be a Const node).