Blog Post: Beating std::visit Without Really Trying

[Adam D. Ruppe]

On Sunday, 6 October 2019 at 07:18:37 UTC, Joseph Rushton 
Wakeling wrote:
> Speaking of performance, I was intrigued by the Reddit response 
> noting that Rust can go one better by eliminating the error 
> path at compile time:

D can eliminate error paths at compile time too, e.g. static 
assert - which can be used to create all kinds of new useful 
errors. So I am guessing this is just a case of the code needing 
a lil tweak or the compiler being conservative and putting the 
code in even though it is never supposed to happen (like final 
switch keeps an error path because you can do like 
cast(some_enum) value_not_in_enum.... and then better to have the 
assertion failure than UB.)