splicing-parameterize always yields void

[camoy]

What version of Racket are you using?
e.g., 8.11.1 [cs]

What program did you run?
Please include a short example that triggers the bug

Running at the top-level with racket/splicing enabled: (splicing-parameterize () 1)

What should have happened?

Should gave back 1, as ordinary parameterize does. Instead it gives void.

Please include any other relevant details

splicing-parameterize creates a top-level variable to hold the parameterization which it then deallocates with set! as it's last expression. It's this set! that is causing the void.

[usaoc]

This appears to be a somewhat intended behavior, because splicing-parameterize is “splicing” like begin, unless it’s in an expression context (try wrapping it in #%expression!). It’s the same as if you evaluate (begin 1 (void)) in the REPL: in reality, two forms will be spliced into the module body, but the REPL will print nothing. I’m not sure there’s an apparent “fix”.

Edit: One thing that’s really problematic, I think, is that the expansion makes it that the last definition form is no longer the last form, which changes the semantics.

Edit 2: Upon a further reflection, the above point doesn’t matter, because it only applies to top-level/module contexts.