Jira issue originally created by user mathroc:
when "_platform->supportsSequences()", a sequence can be droped twice
Comment created by @beberlei:
Fixed in DBAL now by using SplObjectStorage to have only one unique sequence to drop (same for tables and foreign keys)
Issue was closed with resolution "Fixed"
Imported 1 attachments from Jira into https://gist.github.com/aefb4009fed09d858504