1a64e570c6
check object safety of generic constants As `Self` can only be effectively used in constants with `const_evaluatable_checked` this should not matter outside of it. Implements the first item of #72219 > Object safety interactions with constants r? @oli-obk for now cc @nikomatsakis
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.