[ccleve]

The performance hit you take for doing dynamic dispatch is real and measurable. It's a no-go if you're in a performance sensitive part of your app.

[j-krieger]

I write rust for no_std embedded devices and I just use stack_dst for this :)

Of course you‘re right if you can‘t alloc, you can‘t use Box or similar stuff.

Also you can avoid a lot of performance hits if you just implement most stuff on the dyn Trait directly!

[surajrmal]

Sure but most code paths are not hot. This is definitely premature optimization at the expense of everything else.