Pixel 3 name leaked by Google
Actually, the leak that gives away the Pixel 3 name comes from Google itself. Found in a commit on its Android Open Source Project website titled "Cherrypick 'Add device config to decide which Auto Selection Network UI to use'," is a sentence that gives away the name of the upcoming 2018 series. It reads, "This change added the config because the HAL V_1_2 only supports Pixel 3, and the new Auto Selection Network UI is based on HAL V_1_2."
Besides the mention of a Pixel 3, it is interesting that the HAL V_1_2 seems to be exclusive to the next Pixel model. HAL (Hardware Abstraction Level) refers to Project Treble. The latter helps separate the high-level Android OS framework from low-level hardware code. This makes it easier and faster to push out new builds of Android since the low-level hardware code does not have to be repeated in an update.
So now you know, as if there were any doubt, that we should see the Pixel 3 and Pixel 3 XL greet the light of day some time later this year.
source: AOSP via XDA