What is the exact feature or behavior required?

Conversion function from onechar to char.

One or more example use cases for the feature, including sample expected input and output.

There's a situation in SIMPLEXpress that might be better rewritten as a switch case, but because onechar doesn't convert to char, it doesn't work at all. (no suitable conversion function from "onechar" to "char" exists)

An explanation of why the feature is needed. This is important to prioritization. “It would be nice if...” takes a backseat to “This common scenario doesn’t work without...”.

Being able to convert from a onechar to a char where possible (presumably this would be much more difficult on a character outside of char's range) makes as much sense as being able to convert from onestring to std::string.

Any initial ideas you have on implementation (if applicable).