Extra machine state for CTFE, and the Machine instance
When const-evaluation errors, this type is constructed with the resulting information, and then used to emit the error as a lint or hard error.
Evaluates a constant and turns it into a type-level constant value.
def_id is an unstable const fn and what feature gate is necessary to enable it
Tries to destructure constants of type Array or Adt into the constants of its fields.