'rustc' panicked at 'Box<Any>', when const expr evaluation panics

[Kixunil]

After seeing this amusing workaround for conditions in const expr, I decided to try it out. Then I was wondering what would happen if I caused index out-of-bounds. That led me to this code.

While it correctly points to the error, it also says "the compiler unexpectedly panicked. this is a bug." and asks for reporting, so I'm reporting here.

[Mark-Simulacrum]

cc @eddyb

[eddyb]

Works correctly on beta and nightly, doesn't it?

[Kixunil]

@eddyb I totally forgot to check nightly. Indeed, it's correct there.