[Bug c++/90805] Overflow in switch case is not detected

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90805

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Yeah, in switch we have:

  case constant-expression :

where the constant-expression shall be a converted constant expression of the
adjusted type of the switch condition.  And narrowing is not allowed in a
converted constant expression.

I'll try to take a look before long.