Builder with all const methods

[songzhi]

Since const_panic is stablized, I guess it's easy to generate a Builder with all const methods? At least for the simple structs.

[TedDriggs]

How would this interact with existing builder and setter options? Would this be a new builder pattern, alongside owned, immutable, etc?

[TedDriggs]

In the absence of a use-case for this (and the complexity that seems likely as this interacts with other builder settings) I'm closing as "Won't Do"