While reading our documentation about pseudo-types [1] I noticed that it says:
""" anyelement - Indicates that a function accepts any data type anyarray - Indicates that a function accepts any array data type """
This may give an impression that anyelement and anyarray can be used as an argument ("accepted") but not as a return value, while in fact they can. In particular we have [2]:
Should we be slightly more precise here?
I'm fine with the status quo for these. The table entry points out the pertinent part - that they must be used on at least one input argument. The various texts both in 8.21 and 36.2 describing usage and overall behavior make it clear they can appear also on the return type clause so long as they also appear in the input arguments. The functions themselves morph strictly upon the types used in the input arguments.
