I hope it is not very surprising that calling `example` on, e.g., `3` transmuted to `bool` is Undefined Behavior (UB).
When compiling `if`, the compiler assumes that `0` and `1` are the only possible values; there is no saying what could go wrong when that assumption is violated.
(This is a compiler-understood *validity invariant* that is fixed in the language specification, which is very different from a user-defined *safety invariant*.
I hope it is not very surprising that calling `example` on, e.g., `3` transmuted to `bool` is Undefined Behavior (UB).
When compiling `if`, the compiler assumes that `0` and `1` are the only possible values; there is no saying what could go wrong when that assumption is violated.
(This is a compiler-understood *validity invariant* that is fixed in the language specification, which is very different from a user-defined *safety invariant*.