Test if a type conforms to a non-existential protocol

[dabrahams (Dave Abrahams)]

@Nevin

Specifically, if you take your struct that conforms to the opener protocol, and constrain its generic type (the proxy) to have non-trivial conformances on the associated types of its associated type (and provide corresponding constraints on the top-level call site), then the program compiles but the receive method crashes at runtime. Even attempting to print(self) crashes!

Is that a compiler bug?

Thanks for your explanation, Nevin! I'm looking forward to digging into it, but I have another dissertation to read and respond to first…