entity.pickup_position check is based on entity.position

[Mylon]

Normally inserters have to have the pickup_position and dropoff_position set to some integer + 0.5, but if the inserter itself has the "placeable-off-grid" flag then this normal rule does not apply and instead this decimal component must be close to the decimal component of the inserter position itself. Setting the pickup position of this custom inserter to a normal inserter position can cause errors.

To recreate:
Use a custom inserter with the placeable-off-grid flag and allow_custom_vectors set to true.
Set the inserter's position to 0,0
try to set the inserter's pickup_position to {0.5, -0.5} (a valid position for an inserter at {0.5, 0.5})
Error, destination is too close to tile edge.

Expected:
Inserter allows setting pickup_position to {0.5, -0.5}, but errors trying to set pickup_position to {0, -1}
OR
Inserter gives no error, allowing any pickup_position.

http://imgur.com/a/0Edhz

[posila]

Thanks for the report.
Fixed for next release.