The GDPR is not a clarification of the ePrivacy directive, on the contrary. The ePrivacy directive "particularises" certain aspects of the GDPR. National implementations of the ePrivacy directive (which, unlike the GDPR, needed to be put in laws within each EU country) that e.g. regulate certain aspects of electronic communication have priority over the GDPR as a "lex specialis". Wherever such provisions do not exist, the GDPR takes precedence as a "fallback legislation".
The EU is working on an ePrivacy regulation btw, which will indeed replace the ePrivacy directive, but it's not likely that it will be passed before 2021 or 2022.
If you don't trust my word on this you might want to check out the official stance of the European Data Protection Board on this (from 2019): https://edpb.europa.eu/sites/edpb/files/files/file1/201905_e...
The EU is working on an ePrivacy regulation btw, which will indeed replace the ePrivacy directive, but it's not likely that it will be passed before 2021 or 2022.