getImpl on types return incorrect tree in when branches

[mratsim]

getImpl on types returns an incorrect AST with when branches in a typesection.

Example case:

import macros

type
  TrustedSig = object
  ValidatorSig = object

  Untrusted = object
  SigVerified = object
  Trusted = object

  CommitteeValidatorsBits = object
  AttestationData = object

  Attestation*[TrustLevel] = object
    aggregation_bits*: CommitteeValidatorsBits
    data*: AttestationData
    when TrustLevel is SigVerified|Trusted:
      signature*: TrustedSig
    else:
      signature*: ValidatorSig


macro collectImpl(x: type): untyped =
  let typeAst = getType(x)[1]
  let typeImpl = getImpl(typeAst) # <----- no IdentDefs in when section
  echo typeImpl.treerepr
  echo "---------------------------------"
  let typeImpl2 = getTypeImpl(typeAst)
  echo typeImpl2.treerepr

  result = newStmtList()

collectImpl(Attestation[Untrusted])

# TypeDef
#   Sym "Attestation"
#   GenericParams
#     Sym "TrustLevel"
#   ObjectTy
#     Empty
#     Empty
#     RecList
#       IdentDefs
#         Postfix
#           Ident "*"
#           Ident "aggregation_bits"
#         Sym "CommitteeValidatorsBits"
#         Empty
#       IdentDefs
#         Postfix
#           Ident "*"
#           Ident "data"
#         Sym "AttestationData"
#         Empty
#       RecWhen
#         ElifBranch
#           Infix
#             Sym "is"
#             Sym "TrustLevel"
#             Type
#           Sym "signature" <--------------------- Type disappeared
#         Else
#           Sym "signature" <--------------------- Type disappeared
# ---------------------------------
# ObjectTy
#   Empty
#   Empty
#   RecList
#     IdentDefs
#       Sym "aggregation_bits"
#       Sym "CommitteeValidatorsBits"
#       Empty
#     IdentDefs
#       Sym "data"
#       Sym "AttestationData"
#       Empty
#     RecWhen
#       ElifBranch
#         Infix
#           IdentDefs
#             Sym "is"
#             ProcTy
#               FormalParams
#                 Sym "bool"
#                 IdentDefs
#                   Sym "x"
#                   Sym "T"
#                   Empty
#                 IdentDefs
#                   Sym "y"
#                   Sym "S"
#                   Empty
#               Empty
#             Empty
#           IdentDefs
#             Sym "TrustLevel"
#             Sym "TrustLevel"
#             Empty
#           Type
#         IdentDefs
#           Sym "signature"
#           Sym "TrustedSig"
#           Empty
#       Else
#         IdentDefs
#           Sym "signature"
#           Sym "ValidatorSig"
#           Empty

Another instance of nim-lang/RFCs#44