stagedfunction called by a function gets staged twice

[mauro3]

julia> stagedfunction f(x)
           @show "staged f here", x
           :(2*x)
       end
f (generic function with 1 method)

julia> # the staged part gets called once:
       f(5)
("staged f here",x) = ("staged f here",Int64)
10

julia> ff(x)  = f(x)
ff (generic function with 1 method)

julia> # Now the staged part gets called twice:
       ff(6)
("staged f here",x) = ("staged f here",Int64)
("staged f here",x) = ("staged f here",Int64)
12

I would have expected, that the staged part of f to be called only once in total. And for sure not twice in a row in ff(6).

[JeffBezanson]

Staged functions should definitely not have side effects. The compiler can
call them whenever and however many times it wants.

[mauro3]

Thanks for the clarification. Maybe something to put into the docs once they get written.

[mlubin]

It seems like this is just a performance issue.

[Keno]

Yes, a known performance issue. Related to type inference and the method cache being two separate caches.