Result (char c, int prefixLength, Lookup lookup) { final LookupElement item = lookup.getCurrentItem(); if ('.' == c && item != null && item.getObject() instanceof PsiFileSystemItem) { PsiReference referenceAtCaret = lookup.getPsiFile().findReferenceAt(lookup.getLookupStart()); if (referenceAtCaret != null && FileReference.findFileReference(referenceAtCaret) != null) { return Result.ADD_TO_PREFIX; } } return null; }