Linker Error with Template Function

[Paul Backus]

On Tuesday, 13 September 2022 at 00:57:58 UTC, Kyle Ingraham 
wrote:
> I am writing a library where I would like to be able to store 
> instances of a type of class to an associative array for later 
> usage. Each class stored has to implement a function as part of 
> the required interface. The argument given is always the same 
> type but the return value should be flexible. I solved this 
> with an interface:
>
> ```d
> interface PathConverter
> {
>     T toD(T)(const string value) @safe;
> }
> ```

https://dlang.org/spec/template.html#limitations

> Templates cannot be used to add non-static fields or virtual 
> functions to classes or interfaces.

You *should* get an error from the compiler for trying to do 
this, instead of just a linker error somewhere else down the 
line, but either way it's not going to work. You'll have to find 
another solution.