"Compiler Bug: At this point in the compilation typechecking should not infer new types anymore, but it did." with select statement and enum types

[apinski-cavium]

While trying to understand the type rules for select since I would have expected serializable enums to "decay" (implict cast) into their underlaying type (but it does not and it is partly inconsistent with the rest of the specifications really) I found this issue:
Take:

enum bit<8> myenum {  value = 0 }
parser MyParser1(in  myenum a) {
    state start {
        transition select(a) {
                1 .. 22: state1;
                _: accept;
        }
    }
    state state1 {
        transition accept;
    }
}

With p4c we get:

t.p4(8): [--Werror=type-error] error: SelectExpression
        transition select(a) {
                   ^
  ---- Actual error:
  t.p4(1): Cannot unify type 'bit<8>' with type 'myenum'
  enum bit<8> myenum
              ^^^^^^
  ---- Originating from:
  t.p4(1): 'match' case label type 'bit<8>' does not match expected type 'myenum'
  enum bit<8> myenum
              ^^^^^^
In file: /home/apinski/src/p4/p4c/frontends/p4/typeChecking/typeChecker.cpp:161
Compiler Bug: At this point in the compilation typechecking should not infer new types anymore, but it did.

Note the error message also does not point to which case lable either, it just points to the enum type but that is a different issue.