should `local' create local variables when they exist in the tempenv?

[Grisha Levit]

When a variable is present in the temporary environment and then declared
local in a function, it seems to not actually make a local variable, in the
sense that the variable does not show up in the output of `local',
unsetting
the variable reveals the variable from the higher scope rather than marking
it invisible, etc.

    $ f() { local v=x; local -p; }; v=t f

    $ f() { local v; declare -p v; }; v=t f
    declare -x v="t"

    $ f() { local v=x; unset v; declare -p v; }; v=g; v=t f
    declare -- v="g"

Is this intentional?