DMD64 2.095.1 unresolved _D4core8internal7switch___T14__switch_error in optimized build only

[MoonlightSentinel]

On Friday, 9 April 2021 at 11:36:21 UTC, x3g6h7k8 wrote:
> The interesting point is this happens only in optimized builds. 
> In debug builds everything is fine.

Looks like DMD skips the codegen for this template instance 
because it erroneously assumes that the template is already 
emitted in another object file.
This decision is probably affected by some code in a `debug`  
statement which makes it work when compiling with `-debug`.

You can try to compile the release version with `-allinst`.