Problem: Missing test file. Solution: Add samples/test000. (Christian Brabandt)
Problem: Not all parts of the quickfix code are tested. Solution: Add more tests. (Yegappan Lakshmanan)
Problem: Quickfix doesn't handle long lines well, they are split. Solution: Drop characters after a limit. (Anton Lindqvist)
Problem: With some regexp patterns the NFA engine uses many states and becomes very slow. To the user it looks like Vim freezes. Solution: When the number of states reaches a limit fall back to the old engine. (Christian Brabandt)