Making one struct work in place of another for function calls.

[Liam McGillivray]

On Wednesday, 17 April 2024 at 02:39:25 UTC, Paul Backus wrote:
> This is called [row polymorphism][1], and it does not exist in 
> D.
>
> You could approximate it by making `someFunction` a template, 
> and accepting any type `T` that has the necessary members 
> instead of only accepting `typeB`. But this is only possible if 
> you are free to modify the definition of `someFunction`.

Is there a way I can replace "`TypeB`" in the function parameters 
with another symbol, and then define that symbol to accept 
`TypeB` as an argument, but also accept `TypeA` which would get 
converted to `TypeB` using a function? I'm willing to make a 
function template if it's rather simple.