The following expression doesn't ReDoS, but Dlint detects it:

re.search(r'(\n.*)+a','\n'*64+'b')

However, this expression does ReDoS:

re.search(r'(\n.*)+a','\n'*64+'b',re.DOTALL)

Fixing this requires a large amount of work for little gain in reducing false positives. The first example doesn't seem very common. We don't currently analyze the flags passed tore functions, so adding this functionality would take considerable work.